INTRO. Essential Course

Transcription

1 INTRO Essential Course

2 CONTENTS 1 Introduction Course Objectives FEA and ANSYS with CivilFEM Finite Element Analysis Solutions by Finite Element Method with CivilFEM ANSYS and CivilFEM Basics Overview Starting ANSYS and CivilFEM Launcher File Management Tab Customization/Preferences Tab High Performance Computing Setup Tab Start ANSYS and CivilFEM The GUI GUI Layout Graphics Window Main Menu Toolbar Menu Icon Toolbar Menu Raise/Hidden Icon Input Window Utility Menu Current Settings User Prompt Info Output Window Other GUI Notes On-Line Help Graphics and Picking CivilFEM: General Analysis Procedure Main Steps Example Description... 56

3 5.3 Setup Codes Units GUI Configuration Preprocessing Materials Element Type Element Attributes Modeling Save Database and Resume Create Finite Element Model Selection and Components Solution Types of loads Solid-Model Loads Solid loads transference process Plot and List Loads Solve The Model Results File Postprocessing Types of ANSYS Postprocessor Graphics CivilFEM Postprocessor Importing Models Introduction Coordinate System Coordinate Systems Global Coordinate System Local Coordinate System Element Coordinate System Nodal Coordinate System Results Coordinate System Display Coordinate System Element types Mesh 200 elements Surface elements

4 Surface Elements Example Contact Elements CivilFEM Materials CivilFEM and ANSYS Materials Coupling Materials definition Structural Steel Material Properties General Properties Analysis and Design Diagrams Steel Properties Code Properties Concrete Material Properties General Properties Analysis Diagram Design Diagram Concrete properties and code properties Reinforcing Steel Material Properties User Material Library List of Materials CivilFEM Cross Sections Cross Section concept Steel Cross Sections Hot Rolled Shapes Library Steel Sections by Dimensions Steel Sections by Plates Steel Sections by Merge Concrete Cross Sections Faces Concrete Reinforcement Export/Import Cross Sections Import ANSYS 2D model to CivilFEM Export CivilFEM sections to ANSYS User Data Base Cross Sections List of Cross Section Cross Section Edition Sections Modification

5 Section Menu Select Menu Edit Menu Concrete Code Properties Shell Vertex Shell Vertex Concept Shell Reinforcement List of Shell Vertex CivilFEM Member Properties Member Properties Concept Steel Member Properties Concrete Member Properties CivilFEM Beam & Shell Properties Beam & Shell Properties and Real Constants Beam & Shell Properties Definition Beam Property Shell Property Beam 188 and 189 elements CivilFEM Solid Models Analysis Solid Section Concept Capturing Solid Sections Load Combinations Typical Problems Main Applications of CivilFEM Combinations General Procedure I. Obtain All possible Load Cases General Procedure II. Combine Results of the Whole Structure by Searching for Specific Targets General Procedure III. Search for a Specific Result at a Specific Location Define Combination Rules Start States Combination Rules Combination window Combinations Tree Tool Bar Information Window

6 Start States List Coefficients window Combination Definition Process Obtain All Possible Load Cases Defining Targets Combine Searching for Targets Point to Combined Results Reading Combined Results Inquiring Concomitance Concrete Check and Design General Concepts D Axial + Bending Check Interaction Diagram D Axial + Biaxial Bending Check D Interaction Diagram Axial + Biaxial Bending Design Shear and Torsion Check and Design Cracking Check Shell Reinforcement Check and Design Results CivilFEM Steel Checking General concepts Eurocode EA BS AISC-LRFD and ASIC-ASD ANSI/AISC N GB CTE DB SE-A ASME BPVC Section III Div.1 SubSection NF (1989) CivilFEM Envelopes Alternatives and Envelopes CivilFEM Seismic Design Time or Frequency Domain?

7 19.2 Frequency Domain What is a Spectrum? Modal Analysis Seismic Design Modes Combination Push Over Analysis CivilFEM Further Training Documentation Element Types Analysis Types

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9 Training Manual CivilFEM INTRO Essentials CivilFEM Release: 13.0 Published Date: March 16, 2012 Registered Trademarks: CivilFEM is a registered trademark of Ingeciber S.A. ANSYS is a registered trademark of ANSYS Inc. All other product names mentioned in this manual are trademarks or registered trademarks of their respective manufacturers. Disclaimer Notice: This document has been reviewed and approved in accordance with the Ingeciber S.A. Documentation Review and Approval Procedures. This Ingeciber S.A., software product (the Program) and program documentation (Documentation) are furnished by Ingeciber, S.A. under a CivilFEM Software License Agreement that contains provisions concerning non-disclosure, copying, length and nature of use, warranties, disclaimers and remedies, and other provisions. The program and Documentation may be used or copied only in accordance with the terms of that License Agreement. Copyright 2012 Ingeciber S.A. Proprietary Data. Unauthorized use, distribution, or duplication is prohibited. All Rights Reserved. CivilFEM INTRO. Essential 9

10 1 Introduction CivilFEM INTRO. Essential 10

11 1.1. Course Objectives 1.1 Course Objectives Welcome to the ANSYS and CivilFEM Training Course! This training course covers the basics of how to use ANSYS and CivilFEM for static analyses. It is intended for all new ANSYS and CivilFEM users. The aim of this course is to teach the basics of ANSYS and CivilFEM in the following areas: ANSYS and CivilFEM capabilities, basic terminology and the GUI. How to perform a complete analysis the basic steps involved. Building solid models and meshing. Applying loads and solving. Reviewing results and Postprocessing (load combinations, code checking, etc). CivilFEM INTRO. Essential 11

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13 2 FEA and ANSYS with CivilFEM CivilFEM INTRO. Essential 13

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15 2.1 Finite Element Analysis 2.1. Finite Element Analysis 2.1 Finite Element Analysis Finite Element Analysis is a way to simulate loading conditions on the design and determine the design s response to those conditions. Design is modeled using discrete building blocks called elements. Each element has exact equations that describe how it responds to a certain load. The sum of the response of all elements in the model gives the total response of design. The elements have a finite number of unknowns, hence the name finite elements. Historical Note The finite element method of structural analysis was created by academic and industrial researchers during the 1950s and 1960s. The underlying theory is over 100 years old and was the basis for pen-and-paper calculations in the evaluation of suspension bridges and steam boilers. The finite element model, which has a finite number of unknowns, can only approximate the response of the physical system, which has infinite unknowns. So the question arises: How good is the approximation? Unfortunately, there is no easy answer to this question. It depends entirely on what you are simulating and the tools you use for the simulation. We will, however, attempt to give you guidelines throughout this training Physical System course. F.E. Model CivilFEM INTRO. Essential 15

16 2.1. Finite Element Analysis In general, the finite element method allows the user to obtain the displacements in the nodes from the external applied forces. By means of the assigning the element type, material properties, and real constants (inertia, length...), the stiffness matrix will be constructed for every element. The system stiffness matrix can be formed by directly superimposing the elemental stiffness matrices. The size of [K] depends on the total number of nodal displacements of the entire structure; whereas the size of elemental stiffness matrices depends on the number of nodal displacements per element.... [M] x + [C] x + [K] x = [F] [K e ]= Ke II K e JI K e IJ K e JJ Element stiffness matrix I J K e II K e IJ I [K]= K e JI K e JJ J F K u I J Global stiffness matrix CivilFEM INTRO. Essential 16

17 2.1. Finite Element Analysis To create the equations system that will describe the model s behavior, we must assign the following information: Element Type Element type to use according to the model dimensions, DOF and analysis type. Real Constants and Beam and Shell Properties Section properites which depend on element type: Area, inertia, height... Material: Type and Properties Modulus of elasticity, density,poisson coefficient The selection of the element type to generate the model is an important step because it will affect the final results as well as the time of calculation of the model. Element type: Degrees of Freedom Set(DOF) Thermal element one degree of freedom: TEMP. Estructural element six degrees of freedom : UX, UY, UZ, ROTX, ROTY, ROTZ. Element Form Hexahedron, tetrahedron, quadrilateral, triangle, line, etc. Dimension 2-D.Only X-Y plane 3-D. Line, surface or solid elements Kind of Displacements Quadratic Linear CivilFEM INTRO. Essential 17

18 2.1. Finite Element Analysis Every finite element type has an associated form function which is a polynomial that defines the displacements in the whole element from the displacements obtained at the nodes. Each element has an associated form function: o Polynomial that defines the displacement in all the element points depending on the displacements obtained at the nodes. o We can determine the structure s behavior from the nodes behavior generated in the model. The element order is determined by the degree of the form function. Increasing the degree: Increases the precision of the method. Increases the time resolution of the problem. By increasing the number of elements, the precision of the results will improve, but time of calculation will increase as well. Quadratic distribution of D.O.F values Linear approximation (bad results) Real quadratic curve Approximation with elements (better results) Quadratic approximation (The best results) CivilFEM INTRO. Essential 18

19 2.1. Finite Element Analysis Summary: Calculation method by means of finite elements with ANSYS and CivilFEM Once the model is complete: 1. Apply the forces on the structure. 2. Define the restrictions, supports, and the compatibility equations. 3. Calculate. 4. Obtain displacements in nodes. 5. Obtain the displacements for every point of the structure with the form function of the every element. 6. With the deformed shape and the constitutive loads, obtain the stresses. 7. Obtain the strains by integration of the stresses. CivilFEM INTRO. Essential 19

20 2.2. Solutions by Finite Element Method with CivilFEM 2.2 Solutions by Finite Element Method with CivilFEM 2.2 Solutions by Finite Element Method with CivilFEM Analysis type: Static Nonlinear Modal Harmonic Transitory Spectral Buckling Nonlinear Analysis: Nonlinearities of material Nonlinear elasticity Hiperelasticity Viscoelasticity Creep Concrete Non-geometric linearities Large deflection Large rotation Stiffness under stress Change of states Cables Contacts Birth and death of elements CivilFEM INTRO. Essential 20

21 3 ANSYS and CivilFEM Basics CivilFEM INTRO. Essential 21

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23 3.1. Overview 3.1 Overview The ANSYS and CivilFEM program can be run in an interactive mode or a batch mode. In the interactive mode (default mode), you can exchange information with the computer continuously. You can execute a command by selecting its menu path in the GUI or by typing it directly. The ANSYS and CivilFEM program processes the command in real time. Interactive mode allows you to use the GUI, online help, and other various tools to create the engineering model in the graphics window and modify it as you work through the analysis. In batch mode, you submit a file of commands to the ANSYS and CivilFEM program. This command file may have been generated by a previous ANSYS and CivilFEM session, by another program, or by creating a command file with an editor. On some operating systems, you can run a batch job in the background while completing other tasks on the computer. Batch mode is useful when you do not need to interact with the program, such as during the solution phase of an analysis. 3.1 Overview Two ways of working with ANSYS and CivilFEM: Interactive and Batch Modes Interactive mode allows you to interact live with the program, reviewing each operation as you go. Of the three main phases of an analysis preprocessing, solution, and postprocessing the preprocessing and postprocessing phases are best suited for interactive mode. Batch mode allows you to submit a batch file of commands which ANSYS and CivilFEM process in the background. We will mainly cover interactive mode in this course. 3.2 Starting ANSYS and CivilFEM From the Windows Start Menu, select the CivilFEM program s group and then use the ANSYS + CivilFEM entry to run the ANSYS and CivilFEM program with previously selected program settings. To modify these settings, use the Product Launcher. CivilFEM INTRO. Essential 23

24 3.2. Starting ANSYS and CivilFEM 3.2 Starting CivilFEM Launcher Allows you to start CivilFEM and other CivilFEM utilities by pressing buttons on a menu. Start > Programs > CivilFEM XX* The Product Launcher brings up a dialog box containing start-up options: (*) XX is the number of the version From the ANSYS or CivilFEM Start Menu, you can select other options in addition to the launcher: Utilities (administration, animate, ) Help CivilFEM Internet Update Use the Product Launcher to select product settings, such as the simulation environment, the specific license, or any add-on modules or analysis type you want to run. Based on your product selection, you can then specify file management, customization/preferences, and solver setup options. Product settings and options under each tab are explained below. All options may not be displayed, depending on your product selection. Launcher Here, specify your simulation environment, license, and add-on modules. The simulation environment allows the user to choose an interactive interface or to start a batch run. Options include: ANSYS Workbench ANSYS ANSYS Batch CivilFEM INTRO. Essential 24

25 3.2. Starting ANSYS and CivilFEM MFX - ANSYS/CFX LS-DYNA Solver Depending on which environment you select and what licenses are available, the product selection choices or options under the following tabs may vary. CivilFEM is only available in the ANSYS environment. In the License field, select a license from the available types. Only those licenses that are both available at your site and valid with the simulation environment selected will be shown. Launcher has a combo menu used to select the Simulation Environment (select ANSYS Environment) in the top of the window. Available licenses and add-on modules can be selected here. Other tabs below include: File Management, Customization/Preferences, and High Performance Computing Setup. File Management Tab This tab contains the information necessary to manage your files, such as the location of your working directory and job name. The available options will differ depending on the simulation environment you selected. If you selected the ANSYS simulation environment, you can specify: Working directory: Sets the directory in which the ANSYS and CivilFEM run will be executed Job Name: Defines the base filename used for all files generated by the ANSYS and CivilFEM run. If you selected the ANSYS Batch simulation environment, you can specify the above items as well as the following: Input file: Specifies the file of ANSYS and CivilFEM commands you are submitting for batch execution CivilFEM INTRO. Essential 25

26 3.2. Starting ANSYS and CivilFEM Output file: Specifies the file to which ANSYS and CivilFEM directs text output by the program Include input listing in output: Includes or excludes the input file listing at the beginning of the output file File Management Tab - used to specify the Working Directory (Where all of your files will reside) and a Job Name of your choosing. Customization/Preferences Tab The options under this tab allow you to specify detailed settings about your working environment, such as memory settings, parallel/distributed processing settings, custom executables, and additional parameters. The available options will differ depending on the simulation environment you selected on the first tab. CivilFEM INTRO. Essential 26

27 3.2. Starting ANSYS and CivilFEM Customization Tab - used to set memory options. Preferences Tab - used to set the GUI Language and to specify a Graphics Device. Two customizable files called start.ans and stop.ans can also be read at the beginning and end of interactive session. You can specify commands to be executed at program start-up in the start.ans file. For example, if you frequently use certain functions during an ANSYS/CivilFEM session, you might define them as abbreviations/buttons; these abbreviations can be defined in the start.ans file. By default, ANSYS/CivilFEM reads start.ans at the beginning of an interactive session, but does not read it during a batch session. High Performance Computing Setup Tab For detailed information on using this tab, see the Performance Guide in ANSYS Help. This tab is not available in all simulation environments. CivilFEM INTRO. Essential 27

28 3.2. Starting ANSYS and CivilFEM Advanced options for distributed solvers can be selected in the last tab. Start ANSYS and CivilFEM After choosing the desired start-up options, press the Run button to start CivilFEM. Start CivilFEM CivilFEM INTRO. Essential 28

29 4 The GUI CivilFEM INTRO. Essential 29

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31 4.1. GUI Layout 4.1 GUI Layout You use the GUI to communicate with ANSYS and CivilFEM interactively. Each GUI interaction produces ANSYS and CivilFEM commands to perform the operation. Most of the tasks used in ANSYS and CivilFEM can be performed either interactively or by inputting the appropriate commands. The GUI allows you to perform an analysis with little or no knowledge of the ANSYS and CivilFEM commands, while still adhering to the command level operations. 4.1 GUI Layout Utility Menu Input Line Raise/Hidden Icon Icon Toolbar Menu Output Window Main Menu Abbreviation Toolbar Menu Graphics Area Contact Manager Icon Model Control Toolbar User Prompt Info Current Settings CivilFEM INTRO. Essential 31

32 4.1. GUI Layout The layout can be customized Moving the left line resizes the Main Menu area Moving the top line resizes the Toolbar area You can save your customized layout using Utility Menu > MenuCtrls > Save Menu Layout 1. Graphics window Displays the location of model entities, postprocessing contours, and postprocessing graphs. Graphics Area CivilFEM INTRO. Essential 32

33 4.1. GUI Layout Graphics Window 1. Graphics window Displays the location of model entities, postprocessing contours, and postprocessing graphs. Graphics Area This window is where graphics displays are plotted. It is usually the largest of the GUI windows. The Capture Image function (Capture Image button in the Standard Toolbar or Utility Menu> PlotCtrls> Capture Image) allows you to create snapshots of the Graphics Window. After an image is captured you can save it to a file and then restore it in any ANSYS and CivilFEM session. Captured images are useful for comparing different views, sets of results, or other significant images simultaneously on the screen. Click the right mouse button to access many functions that can adjust the Graphics Window display. The available information will vary according to the type of display and the position of the cursor in the window. Along with some of the standard Pan-Zoom-Rotate functions, you can also access many of the window control functions in the PlotCtrls section of the Utility Menu. Main Menu The Main Menu is where you begin your analysis. It contains the ANSYS and CivilFEM analysis functions you use to create your model and perform the analysis. The Main Menu is arranged in a tree structure. This structure makes progressive submenus accessible as you proceed through the steps of the analysis. Each menu topic in the Main Menu either expands to show more menu CivilFEM INTRO. Essential 33

34 4.1. GUI Layout options (indicated by a boxed +) or performs an action (indicated by an icon preceding the menu topic). 2. Main Menu General part The main menu is made up of two parts: General Purpose part and Specific Civil Engineering part. Tree structure format. Civil part Contains the main functions required for an analysis. Scroll bar Use scroll bar to gain access to long tree structures. Expand All option Position mouse cursor on branch of Main Menu then select right mouse button The option to expand the branch is displayed Selecting Expand All expands the branch contents CivilFEM INTRO. Essential 34

35 4.1. GUI Layout You can set your menus to automatically collapse and expand your subtopics. Use the Collapse Siblings feature (found in the right mouse click menu) to set your menu expansion preferences. When you choose collapse, the subtopics you have open automatically collapse when you choose another main topic. Expand Headings and Collapse Sibling Right Click in Main Menu and select Preferences. Level color, filtering and expansion of Main Menu can be changed. You use the same right mouse click context-sensitive control to configure the main menu for selectable contrasting color display within each nested level. You can designate any color for the menu text at each level, making the transition between levels easily detectable. CivilFEM INTRO. Essential 35

36 4.1. GUI Layout With Expand headings and Collapse siblings behavior active Creating a Volume branch open When the Delete branch is opened, the Create branch is closed Note, inactivate Collapse siblings to keep open the Create branch Filtered Branches Main Menu with structural and thermal element type defined Main Menu with only thermal element type defined Only Apply branches shown are those for defined element types One of the most useful customizations you can perform from the GUI is to apply filtering to your menu choices. Filtering lets you grey out, or completely hide many of the functions that will not be needed during your analysis. The preferences dialog box is used to adjust filtering. CivilFEM INTRO. Essential 36

37 Toolbar Menu 4.1. GUI Layout The Toolbar Menu is a convenient area where you can add push-buttons for command, function, and macro shortcuts. These push buttons execute commonly used ANSYS and CivilFEM functions. 3. Toolbar Menu Contains abbreviations short-cuts to commonly used commands and functions. You can create your own button menu system, but it requires knowledge of ANSYS and CivilFEM commands. You can create abbreviations either through the *ABBR command or through the Utility Menu> Macro> Edit Abbreviations or Utility Menu> MenuCtrls> Edit Toolbar menu items. Using one of the menu items is preferable for two reasons: Clicking OK automatically updates the toolbar (using the *ABBR command requires that you use the Utility Menu> MenuCtrls> Update Toolbar menu item to make your new abbreviation appear on the toolbar). You can easily edit the abbreviation if required. Toolbar buttons are not consistent from one ANSYS and CivilFEM session to the next; however, they are saved and maintained in the database so that any "resume" of the session will still contain these abbreviations. To save your custom button definitions, you must explicitly save them to a file through the Utility Menu> MenuCtrls> Save Toolbar menu item (ABBSAV command) and restore them for each session using the Utility Menu> MenuCtrls> Restore Toolbar menu item (ABBRES command). CivilFEM INTRO. Essential 37

38 Icon Toolbar Menu 4.1. GUI Layout When you begin your ANSYS and CivilFEM session, the start-up routine reads a number of text files and scripts that set parameters and conditions for your ANSYS and CivilFEM session. Many of these files can be modified to provide a more customized level of operation. The start.ans file is one such file. You call up toolbars, set their position and define their content in a similar fashion. You can list the toolbars in the tlbrlistxxx.ans file (where XXX is the ANSYS and CivilFEM version number). This file contains a list of the toolbars activated at start up. The toolbar filenames are designated as *.TLB files, and each file in the list contains the specifications for the content, appearance, and position of the toolbars in the ANSYS GUI. You can add additional toolbars to the GUI (including a Pan-Zoom-Rotate functionality button bar, ANSYSGRAPHICAL.TLB, that is included with the program) by creating the corresponding *.TLB files and including them in the tlbrlistxxx.ans file. The default tlbrlistxxx.ans file loads the Standard Toolbar by calling the file \ANSYSSTANDARD.TLB and the ANSYS Toolbar by calling the file \ANSYSABBR.TLB. These files should be placed in the same directory as your tlbrlistxxx.ans file, although the files themselves can be placed anywhere as long as the proper path string is designated and remains valid. For more information about creating a toolbar file you can see the chapter of the Operations Guide in the ANSYS help documentation. 4. Icon Toolbar Menu Contains icons of commonly used functions. Can be customized by the user. (i.e. adding icons, additional toolbars) Open ANSYS File Save Analysis Pan-Zoom-Rotate Image Capture Report Generator New Analysis ANSYS Help The standard buttons and their functions include: CivilFEM INTRO. Essential 38

39 4.1. GUI Layout New Analysis: Saves and clears information for the existing analysis and starts a new analysis. Open ANSYS and CivilFEM File: Opens ANSYS and CivilFEM database or input files to be read into ANSYS and CivilFEM. The file type determines the operation. Save Analysis: Saves the current analysis to a database file. Pan-Zoom-Rotate: Opens the Pan-Zoom-Rotate dialog box. Image Capture: Opens the image capture GUI. Report Generator: Opens the report generator GUI. ANSYS Help: Displays the table of contents for the ANSYS HTML-based help. Raise/Hidden Icon The Raise/Hidden Icon has been introduced to help display hidden ANSYS created windows. This icon is located in the upper right part of the New GUI next to the input window. As an example, consider the hiding of the Pan/Zoom/Rotate widget by the New GUI window. By simply selecting the Raise/Hidden Icon, the Pan/Zoom/Rotate widget is brought to the front and displayed in front of the New GUI. Note, selecting the Raise/Hidden Icon brings forward all hidden ANSYS created windows except the output window. 5. Raise/Hidden Icon The Raise/Hidden Icon can be used to bring to the front any hidden ANSYS or CivilFEM created windows (except the output window). Pan/Zoom/Rotate Widget Hidden Select Raise/ Hidden Icon Pan/Zoom/Rotate Widget Shown CivilFEM INTRO. Essential 39

40 Input Window 4.1. GUI Layout You use the Input Window to conveniently enter single commands and access the history buffer without changing the overall configuration of the GUI 6. Input Window Allows you to enter commands. (All GUI functions actually send commands to ANSYS and CivilFEM. If you know these commands, you can type them in the Input Window). Command format is dynamically displayed until user finishes entering the command. As a command is typed, the format of the command is dynamically displayed As you enter commands into the Input Window, the dynamic command help appears in a box above the window. As you type the letters, the command help displays the possible commands and guides you through the proper spelling and syntax of the command. You can view and access the history buffer by clicking the down arrow on the right of the text entry box. A drop down list containing the entry history appears. Clicking the left mouse button on any line in the history buffer moves that line to the text entry box where you can edit and execute it. A double click on any line in the history buffer automatically executes that line. The vertical scroll bar at the right corner of the history buffer box allows you to scroll through the history buffer. You can also use the up and down arrow keys to navigate the history buffer. CivilFEM INTRO. Essential 40

41 4.1. GUI Layout Reissuing commands List of issued commands Use scroll bar to gain access to all commands issued Commands can be reissued by double-clicking on the listed command Select down arrow to see list of issued commands The up and down arrows on the keyboard can be used to select different listed commands Utility Menu 7. Utility Menu Contains utilities that are generally available throughout the CivilFEM session: graphics, on-line help, select logic, file controls, etc. Conventions used in Utility Menu: indicates a dialog box + indicates graphical picking > indicates a submenu (blank) indicates an action The Utility Menu lists 10 topics: File: Contains file and database related functions, such as clearing the database, saving it to a file, and resuming it from a file. Some of the CivilFEM INTRO. Essential 41

42 4.1. GUI Layout functions under the File menu are valid at Begin level only. If you choose such a function when you are not at Begin level, you will see a dialog box giving you a choice of moving to Begin level and executing the function or cancelling the function. Select: Includes functions that allow you to select subsets of entities and to create components. List: Enables you to list virtually any data item stored in the ANSYS and CivilFEM database. You can also obtain status information about different areas of the program and list the contents of files residing on your system. Plot: Lets you plot keypoints, lines, areas, volumes, nodes, elements, and other data that can be graphically displayed. PlotCtrls: Includes functions which control the view, style, and other characteristics of graphics displays. The Hard Copy function lets you obtain hard copies of the entire screen or just the Graphics Window. WorkPlane: Enables you to toggle the working plane on or off and to move, rotate, and otherwise manoeuvre the working plane. You can also create, delete, and switch coordinate systems by using this menu. Parameters: Includes functions to define, edit, and delete scalar and array parameters. Macro: Allows you to execute macros and data blocks. You can also create, edit, and delete abbreviations, which appear as push buttons on the Toolbar. MenuCtrls: Lets you create, edit, and delete abbreviations on the ANSYS and CivilFEM Toolbar and modify the colors and fonts used in the GUI display. Once you've adjusted the GUI to your liking, you can use the Save Menu Layout function to save the current GUI configuration. Help: Brings up the ANSYS Help System. CivilFEM INTRO. Essential 42

43 4.1. GUI Layout Current Settings 8. Current Settings The current element attributes settings and currently active coordinate system are displayed at the bottom on the GUI. Element Attributes Active Coordinate System User Prompt Info 9. User Prompt Info Instructions to the user are displayed in the lower left hand area of the GUI. The user will be given user prompt info for operations, such as picking operations. User Prompt Info CivilFEM INTRO. Essential 43

44 Output Window 4.1. GUI Layout The Output window receives all text output from the program - command responses, notes, warnings, errors, and any other messages. It is usually positioned behind the GUI, but you can raise it to the front when necessary. 10. Output Window The output window gives the user feedback on how ANSYS and CivilFEM interpreted the user s input. The Output Window is independent of the menus. Caution: Closing the output window closes the entire CivilFEM session! Able to verify the version Other GUI Notes 11. Other GUI Notes Some dialog boxes have both Apply and OK buttons. Apply applies the dialog settings, but retains (does not close) the dialog box for repeated use. OK applies the dialog settings and closes the dialog box. Remember that you are not restricted to using the menus. If you know the command, feel free to enter it in the Input Window! The output window is not affected by the Raise/Hidden Button. For convenience, the user may want to resize the GUI, so part of the output window is displayed to allow easy access. CivilFEM INTRO. Essential 44

45 4.1. GUI Layout On-Line Help 12. On-Line Help CivilFEM has a documentation system which provides extensive on-line help. You can get help on: ANSYS commands CivilFEM commands Element types Analysis procedures Special GUI widgets such as Pan-Zoom-Rotate There are several ways to start the ANSYS or CivilFEM help system: Launcher > Product Help Utility Menu > Help > Help Topics From windows, Start > Programs > ANSYS > Help From windows, Start > Programs > CivilFEM > Help Any dialog box > Help Type HELP,name in the Input Window. Name is a command or element name. An ANSYS dialog box or command is for ANSYS help and a CivilFEM dialog box or command is used for CivilFEM help. As you scan a page of text in the navigation window, you will notice certain words or phrases are underlined and appear in a different color. These items are hypertext links. A hypertext link is a text navigation tool that, when clicked, shows CivilFEM INTRO. Essential 45

46 4.1. GUI Layout information about that item. Typical items which appear as hypertext links are command names, element types, and manual section references. Example ANSYS help Press help Or press: Help,K CivilFEM help Or press: Help,~CFMP Press help Press Alt+126 to write this symbol Pressing the Product Help button on the launcher brings up a help browser with: a navigational window containing Table of Contents, Index, Search Utility and Favorites. a document window containing the help information. CivilFEM INTRO. Essential 46

47 4.1. GUI Layout Use the Contents tab to browse to the item of interest. Use the Index tab to quickly locate specific commands, terminology, concepts, etc. Use the Search tab to query the entire help system for specific words or phrases. ANSYS also provides an on-line tutorial. The tutorial consists of detailed instructions for a set of problems solved in ANSYS. To access the tutorial, click on Utility Menu > Help > ANSYS Tutorials Graphics and Picking Many functions in the ANSYS program involve graphical picking - using the mouse to identify model entities and coordinate locations. CivilFEM INTRO. Essential 47

48 4.1. GUI Layout 13. Graphics and Picking The most heavily used interactive capabilities are graphics and graphical picking. Graphics is used to visualize the model, loading, results, and other input and output data. Picking is used for model creation, meshing, loading, etc. Use Plot in the Utility menu to produce plots or issue the commands shown. /replot kplot lplot aplot vplot nplot eplot gplot The PlotCtrls menu is used to control how the plot is displayed: plot orientation zoom colors symbols annotation animation etc. Among these, changing the plot orientation (/VIEW) and zooming are the most commonly used functions. These functions can also be done with the Model Control Toolbar located in the right side of the window. CivilFEM INTRO. Essential 48

49 4.1. GUI Layout The default view for a model is the front view: looking down the +Z axis of the model. To change it, use dynamic mode a way to orient the plot dynamically using the Control key and mouse buttons or picking in the Model Control Toolbar Ctrl + Left mouse button pans the model. Ctrl + Middle mouse button: zooms the model spins the model (about screen Z) Ctrl + Right mouse button rotates the model: about screen X about screen Y Note, the Shift-Right button on a twobutton mouse is equivalent to the Middle mouse button on a three-button mouse. Ctrl P Z R You also can use the Dynamic Mode setting in the Pan-Zoom-Rotate dialog box. The same mouse button assignments apply. On 3-D graphics devices, you can also dynamically orient the light source. This is useful for different light source shading effects. When using 3-D driver CivilFEM INTRO. Essential 49

50 4.1. GUI Layout Other functions in the Pan-Zoom-Rotate dialog box: Preset views Zoom-in on specific regions of the model Pan, zoom, or rotate in discrete increments (as specified by the Rate slider) Rotation is about the screen X, Y, Z coordinates. Fit the plot to the window Reset everything to default Front +Z view, from (0,0,1) Back -Z view (0,0,-1) Top +Y view (0,1,0) Bot -Y view (0,-1,0) Right +X view (1,0,0) Left -X view (-1,0,0) Iso Isometric (1,1,1) Obliq Oblique (1,2,3) WP Working plane view Zoom By picking center of a square Box Zoom By picking two corners of a box Win Zoom Same as Box Zoom, but box is proportional to window. Back Up Unzoom to previous zoom. Picking Picking allows you to identify model entities or locations by clicking in the Graphics Window. A picking operation typically involves the use of the mouse and a picker menu. It is shown by a + sign on the menu. For example, you can create keypoints by picking locations in the Graphics Window and then pressing OK in the picker. CivilFEM INTRO. Essential 50

51 4.1. GUI Layout Two types of picking: Retrieval picking: Picking existing entities for a subsequent operation. Allows you to enter entity numbers in the Picker Window. To do this, press ENTER before Apply or OK, if you don t do so the program does not pick or unpick any entity. Use the Pick All button to indicate all entities. Example of Retrieval Picker Locational picking: Locating coordinates of a point, such as a keypoint or node. Allows you to enter coordinates in the Picker Window. Example of Locational Picker Whenever you use graphical picking (that is, when you click on a menu topic ending with the + symbol), the GUI brings up a picking menu, sometimes known as the picker. Function Title [1]. Identifies the function being performed. Pick Mode [2]. Allows you to pick or unpick a location or entity For retrieval picking, you also can choose among single, box, polygon, circle, and loop mode. In single pick mode, each click on the mouse picks one entity. With box, polygon, and circle modes, press and drag the mouse to enclose a set of CivilFEM INTRO. Essential 51

52 4.1. GUI Layout entities in a box, polygon, or circle. Loop mode is available for picking lines and areas only. Pick Status [3]. Shows the number of items picked ("Count") and the minimum and maximum number of picks required for the function. Picked Data [4]. Shows information about the item being picked. For locational picking, the working plane and global Cartesian coordinates of the point are shown. For retrieval picking, this area shows the entity number. Keyboard Entry Options [5]. In some cases, you may need to enter the required data by keyboard in the picker. For example, to specify a known coordinate location during locational picking, it may be easier to enter the coordinates than to use the mouse. In that case, you can choose between working plane coordinates and global Cartesian coordinates. For retrieval picking, you can choose between entering a list of entity numbers and a range of numbers. Action Buttons [6]. This area of the menu contains buttons that take action on the picked entities, as follows: - OK: Applies the picked items to execute the function and closes the picking menu. - Apply: Applies the picked items to execute the function but does not close the picking menu. - Reset: Unpicks all picked entities and restores the menu and the graphics area to their state at the last Apply. - Cancel: Cancels the function and closes the picking menu. - Pick All: Picks all entities, executes the selected function, and closes the picking menu. This feature is available for retrieval picking only. - Help: Brings up help information for the function being performed. CivilFEM INTRO. Essential 52

53 4.1. GUI Layout Mouse button assignments for picking: Left mouse button picks (or unpicks) the entity or location closest to the mouse pointer. Pressing and dragging allows you to preview the item being picked (or unpicked). Pick Apply Toggle Pick / Unpick Middle mouse button does an Apply. Saves the time required to move the mouse over to the Picker and press the Apply button. Use Shift-Right button on a two-button mouse. Right mouse button toggles between pick and unpick mode. Note, the Shift-Right button on a twobutton mouse is equivalent to the Middle mouse button on a three-button mouse. Cursor display: Pick Unpick CivilFEM INTRO. Essential 53

54

55 5 CivilFEM: General Analysis Procedure 5.1 Main Steps Regardless of the physics of the problem, the same general procedure can always be followed to run a simulation. A sample model will be used to demonstrate the general analysis procedure. 5.1 Main steps Preliminary Decisions Preprocessing Solution Postprocessing Every analysis involves four main steps: Preliminary Decisions Which analysis type? What to model? Which element type? Select active code and units. Preprocessing Define Element properties (materials, sections ). Create or import the model geometry. Mesh the geometry. Solution Apply loads and boundary conditions. Solve. Postprocessing Do combinations. Review results. Check the validity of the solution. Code checking or design. CivilFEM INTRO. Essential 55

56 5.2. Example Description 5.2 Example Description 5.2 Example description The suggested example is a cantilever shell which has one side built in a concrete box. The adjacent side is joint to a concrete wall which grows from the shell upwards. To improve the behavior of the structure, two steel struts are placed, joining the wall with the box and the wall with the free corner of the shell. Along the free edges of the shell, steel beams are located. The geometry, materials, element types and the loads of the model can be seen in the following slide. The concrete box will be modeled with 3D solid elements, the shell will have Shell elements (movements and rotations DOFs), the struts are modeled with Link elements (axial force only) and the wall is made up by 2D plane elements simulating plane stress Pa Pa 20 m 30 m 15 m 15 m 15 m 5000 N 10 º C 15 m Materials: Steel. EC3: Fe 430 Concrete. EC2: C35/45 Element types: Plane42 Solid45 Beam4 Shell63 Link8 Loads: Self weight Punctual Load: 5000 N Surface Load: Pa Hydrostatic Pressure: Pa (bottom) Thermal Increment: 10 ºC CivilFEM INTRO. Essential 56

57 5.3. Setup 5.3 Setup 5.3 SETUP The first step when working with CivilFEM is to choose the active codes and units. Once you have chosen the units system and have begun your work with CivilFEM, you cannot change the active units system. Remember then to introduce all the data values in the active units system at the beginning! CivilFEM converts all the section dimensions available in the library (including the user cross section library), the active code formulation, etc. to the active units. However, it is important to note that CivilFEM can do this conversion only as a first step. CivilFEM INTRO. Essential 57

58 5.3. Setup Codes Codes Select: Code for Steel Checking Code for Concrete Checking (concrete and reinforced concrete) Code for Prestressed Concrete Code for Seismic Design Units and Code must be selected first and should not be changed later on Steel, reinforced concrete, prestressed concrete and seismic codes can be selected in this window. By default the Eurocodes are shown. See ~CODESEL command. Units Units Select: Length unit Time unit Force, or Pressure/Stress or Mass unit (left as User the other two of them). If a units system is not available in the library, you may use it by defining the conversion factor to international system. CivilFEM INTRO. Essential 58

59 5.3. Setup The units system for all of the calculations is selected in this window. By default, CivilFEM uses the International System (SI). Given that the units are related, only 3 of them may be personalised and the rest are automatically calculated. Results data are given in the corresponding units, and abbreviations must be specified in the second column (in the example: mm, s, kn, uup, uum). See ~UNITS command. GUI Configuration GUI Configuration This tab includes graphical options, interface configurations, background colors, and the following options: Title color and title shadow: These buttons change the title and shadow color for all the GUI. Undo/Redo steps: this number shows the Undo/redo steps available. (When this option is chosen, it is necessary to take into account the memory of the computer and the data base size used). CivilFEM INTRO. Essential 59

60 5.3. Setup Optimize log: This option removes the redundant commands produced when the CivilFEM GUI is used. Data table decimals: Number of decimal places used in the CivilFEM editors. Auto-Fit: Fit the objects in the CivilFEM Graphical windows. Dynamic size axis or Fixed size axis: Option to show the dynamic axis or fixed axis in the CivilFEM editors. Zoom Box: Zone utilized when performing a zoom operation. This can be an inner rectangle selected by the mouse, a bounding rectangle constrained by the graphics area window, or both. Tab Views: The different views for the tabs of the editors are up, down, or the operating system default. The CivilFEM setup window also includes other tabs such as: CF config, Bridges config, Geotechnical config and Prestressed config. CF CONFIG In this section diverse configuration parameters are determined. CivilFEM INTRO. Essential 60

61 5.3. Setup Strength Reduction Factor o Strength reduction factor used for different reinforced concrete codes or standards. Concrete Interaction Diagram Parameters o NED: Number of steps on strains. o NTD: Number of steps on angles. o N2D: Number of steps on 2D analysis. o WMIN: Minimum reinforcement factor. o WMAX: Maximum reinforcement factor. o DELTA: Coefficient to establish the diagram s centre position. o LIMCOUNT: Maximum number of iterations on design. o NMAXDIAG: Maximum number of diagrams stored in file. CivilFEM Result File o RESMAX: Maximum number of records in CivilFEM results file. Shell Result o PLOT: ANSYS result used for plotting CivilFEM shell results. o FORCES AND MOMENTS: How CivilFEM obtains results on shell elements: CivilFEM INTRO. Essential 61

62 5.3. Setup ANSYS Centroid values. Forces and moments are obtained at the centroid of the element and are considered constant for the entire element. CivilFEM node values. CivilFEM calculates the values of forces and moments at each node of the element. BRIDGES CONFIG Bridge configuration parameters. This tab only appears if the Bridge and Civil Non Linearities Module is activated. GEOTECHNICAL CONFIG Geotechnical Module parameters. This tab only appears if the Geotechnical Module is activated. PRESTRESSED CONCRETE CONFIG Prestressed Concrete Module parameters. This tab only appears if the Advanced Prestressed Concrete Module is activated. CivilFEM INTRO. Essential 62

63 5.4. Preprocessing 5.4 Preprocessing Materials Material properties defined by CivilFEM include ANSYS standard properties as well as other properties necessary for CivilFEM specific calculations, such as properties related to codes: characteristic strengths, yield strengths, reduction coefficients, etc. 5.4 PRE-PROCESSING Materials Once you have chosen the units system and the active code, select the materials that will be used. In the CivilFEM s materials window the user may find a list of the materials currently defined in the database. It is possible to choose any of the different materials CivilFEM has in its library. When defining a material with CivilFEM, ANSYS standard properties are defined by assigning ANSYS materials the same numbering as CivilFEM materials. It is not recommended to directly modify material properties with ANSYS, as CivilFEM may later change those properties automatically to coordinate with ones specified in the database, to update time dependent properties, etc. CivilFEM INTRO. Essential 63

64 5.4. Preprocessing Material Properties can be modified A new user material can be defined by choosing USER DEF in the general properties window Example In this example you must define the following materials: CivilFEM INTRO. Essential 64

65 5.4. Preprocessing Element Type Element Type The element type is an important choice that determines the following element characteristics: Degree of Freedom (DOF) set. A thermal element type, for example, has one DOF: TEMP, whereas a structural element type may have up to six DOF: UX, UY, UZ, ROTX, ROTY, ROTZ. Element shape -- brick, tetrahedron, quadrilateral, triangle, etc. Dimensionality -- 2-D (X-Y plane only), or 3-D. Assumed displacement shape -- linear vs. quadratic. Non linear capabilities Details on how to choose the most suitable element type will be presented later. For now, let s see how to define an element type. ANSYS offers many different categories of elements. Some of the commonly used ones are: Linear elements Shells 2-D solids 3-D solids The Civil postprocessor groups the ones most commonly used in Civil Engineering: Structural Beams and Shells. A model built with CivilFEM and ANSYS may have any of the element types of ANSYS library. However, CivilFEM only carries out calculations on certain element types (depending on the kind of calculation) and ignores the remaining ones, which will be used by ANSYS. CivilFEM INTRO. Essential 65

66 5.4. Preprocessing Example To continue the example, the next step is to select the elements to be used. From the complete element list: In this example, the element PLANE42 has plane stress behavior. This behavior is the default for this element type and can be changed using the options window. CivilFEM INTRO. Essential 66

67 5.4. Preprocessing From the structural Civil elements: Element Attributes Element Attributes Calculations within ANSYS and CivilFEM require elements to have the following attributes: Element type: Element type selected depending on the required dimensions of the model, degrees of freedom, type of analysis: LINK1, BEAM3, BEAM4, SHELL, BEAM44, SHELL63... Set of real constants: Data of the section properties, which depend on the element type: Area, Inertia, depth... If you have selected link, beam, or shell elements with CivilFEM you must create the Beam and Shell Properties. Beam and Shell Properties include all the properties required for calculating and postprocessing with CivilFEM: properties of the cross sections (reinforcement data, plates structure, ), member properties, etc. CivilFEM automatically generates the set of real constants. CivilFEM INTRO. Essential 67

68 5.4. Preprocessing ANSYS Section: Replaces the real constants (only valid in certain beams). CivilFEM Beam and Shell Properties will also generate this section automatically if needed. Material (CivilFEM or ANSYS generic material): Material properties: elasticity modulus, density, Poisson s ratio, thermal expansion coefficient... Example Define the cross section of the beam and the thickness of the shell. Don t forget to enter the number of the material Select IPE A 500 for beam section CivilFEM INTRO. Essential 68

69 5.4. Preprocessing Enter the thickness of the shell Don t forget to select the material Next, define the Beam and Shell Properties (and the real constants) for the beam element. Don t forget to enter the type of the element Enter the number of the Beam property The real constants group CivilFEM generates from the Beam and Shell Properties will have the same numbering as the beam and shell properties. CivilFEM INTRO. Essential 69

70 5.4. Preprocessing Enter the number of the shell property Don t forget to enter the type of the element Enter the area of the element CivilFEM INTRO. Essential 70

71 5.4. Preprocessing It is necessary to create a real constant group with its fields left blank for the block and wall mesh. This cannot be done by using a menu, so we must use the following command: Enter in the command window: R,1 Modeling Modeling Definitions: A solid model is defined by volumes, areas, lines, and keypoints. Volumes are bounded by areas, areas by lines, and lines by keypoints. Hierarchy of entities from low to high: keypoints > lines > areas > volumes You cannot delete an entity if a higherorder entity is attached to it. Volumes Areas Lines & Keypoints Volumes Areas Lines Keypoints CivilFEM INTRO. Essential 71

72 5.4. Preprocessing A model with areas and lower-order entities, such as a shell or 2-D plane model, is still considered a solid model in CivilFEM terminology. There are two approaches to creating a solid model: Top-down Bottom-up Top-Down Modeling Top-down modeling starts with a definition of volumes (or areas) which are then combined in some fashion to create the final shape. Initially defined volumes or areas are called primitives. Primitives are located and oriented with the help of the working plane. Combinations used to produce the final shape are called Boolean operations. add CivilFEM INTRO. Essential 72

73 5.4. Preprocessing With ANSYS and CivilFEM, the user can also create a model using geometric primitives, which are fully-defined lines, areas, and volumes. As you define a primitive, the program automatically creates all of the associated "lower" entities. If your modeling effort begins with the "higher" primitive entities, you are said to be building your model "from the top down." You can freely combine bottom-up and top-down modeling techniques, as appropriate, in any model. Primitives are predefined geometric shapes such as circles, polygons, and spheres. 2-D primitives include rectangles, circles, triangles, and other polygons. 3-D primitives include blocks, cylinders, prisms, spheres, and cones. When you create a 2-D primitive, ANSYS defines an area, along with its underlying lines and keypoints. When you create a 3-D primitive, ANSYS defines a volume, along with its underlying areas, lines and keypoints. Use: Utility Menu > Plot > Lines or Keypoints. You can create primitives by specifying their dimensions or by picking locations in the graphics window. The WP is a movable, 2-D reference plane used to locate and orient primitives. By default, the WP origin coincides with the global origin, but you can move it and/or rotate it any desired position. By displaying a grid, you can use the WP as a drawing tablet CivilFEM INTRO. Essential 73

74 5.4. Preprocessing All working plane controls are in Utility Menu > WorkPlane. The WP Settings menu controls are the following: WP display: triad only (default), grid only, or both. Snap: allows you to pick locations on the WP easily by snapping the cursor to the nearest grid point. Grid spacing: the distance between grid lines. Grid size: how much of the (infinite) working plane is displayed. You can move the WP to any desired position using the Offset and Align menus Offset WP by increments Offset WP to > This simply relocates the WP, maintaining its current orientation, to the desired destination, which can be: existing keypoint(s), existing node(s), coordinate location(s), global origin, or origin of the active coordinate system. Align WP with > This reorients the WP. CivilFEM INTRO. Essential 74

75 5.4. Preprocessing Boolean operations are computations involving combinations of geometric entities. Boolean operations include add, subtract, intersect, divide, glue and overlap. All Boolean operations are available in the GUI under Main Menu> Preprocessor> Modeling> Operate>Booleans Add: Combine two or more entities into one. Glue: Attaches two or more entities by creating a common boundary between them (useful when you want to maintain the distinction between entities). Overlap: Same as glue, except the input entities overlap each other. Subtract: Removes the overlapping portion of one or more entities from a set of base entities (useful for creating holes or trimming off portions of an entity). Divide: Cuts an entity into two or more pieces that are still connected to each other by common boundaries. The cutting tool may be the working plane, an area, a line, or even a volume. Intersect: Keeps only the overlapping portion of two or more entities. If there are more than two input entities, there are two choices: common intersection and pairwise intersection: Common intersection finds the common overlapping region among all input entities. Pairwise intersection finds the overlapping region for each pair of entities and may produce more than one output entity Partition: Cuts two or more intersecting entities into multiple pieces that are still connected to each other by common boundaries. Note: When you operate with two (or more) areas, the program assigns a number to the total area by default. This choice is not arbitrary; the program searches for the first free number. CivilFEM INTRO. Essential 75

76 5.4. Preprocessing Bolean Operation Before Boolean Operation Alter Boolean Operation ADD GLUE OVERLAP CivilFEM INTRO. Essential 76

77 5.4. Preprocessing SUBTRACT DIVIDE Common Intersection INTERSECT Pairwise Intersection L2 L6 PARTITION L1 L3 L7 L4 CivilFEM INTRO. Essential 77

78 5.4. Preprocessing Bottom-Up Modeling When building your model from the bottom up, you begin by defining the lowestorder solid model entities: keypoints. Keypoints are defined within the currently active coordinate system. You can then define lines, areas, and volumes connecting these keypoints. You do not always have to explicitly define all entities in ascending order to create higher-order entities; you can define areas and volumes directly in terms of the keypoints at their vertices. The intermediate entities will then be generated automatically as needed. For example, if you define a brick-like volume in terms of the eight keypoints at its corners, the program will automatically generate the bounding areas and lines. Bottom-up modeling starts with keypoints, from which you build up lines, areas, etc. To build an L-shaped object, for example, you could start by defining the corner keypoints as shown below. You can then create the area by simply connecting the dots or by first defining lines and then defining the area by lines. CivilFEM INTRO. Essential 78

79 5.4. Preprocessing Keypoints definition 1. KEYPOINTS To define keypoints: Main Menu > Preprocessor > Modeling > Create > Keypoints The only data needed to create a keypoint is the keypoint number and the coordinate location. Keypoint number defaults to the next available number. The coordinate location may be provided by simply picking locations on the working plane or by entering the X,Y,Z values. To define individual keypoints, use one of the methods listed in the following table: In the active coordinate system At a given location on an existing line Main Menu> Preprocessor> Modeling> Create> Keypoints> In Active CS Main Menu> Preprocessor> Modeling> Create> Keypoints> On Working Plane Main Menu> Preprocessor> Modeling> Create> Keypoints> On Line Main Menu> Preprocessor> Modeling> Create> Keypoints> On Line w/ratio Once you create an initial pattern of keypoints, you can generate additional keypoints and work with existing keypoints using several methods described in ANSYS Help: Modelling and Meshing Guide. Chapter 5.2: Creating Your Solid Model from the Bottom Up. Many Boolean operations will also create keypoints. Hard Points Hard points are a special type of keypoints. You can use hard points to apply loads or to obtain data from arbitrary points on lines and areas within your model. Hard points do not modify either the geometry or the topology of your CivilFEM INTRO. Essential 79

80 5.4. Preprocessing model. Hard points have their own extension in the GUI under the keypoints extension. If you issue any commands that update the geometry of an entity, such as Boolean or simplification commands, any hard points associated with that entity will be deleted. Therefore, it is recommended to add hard points after completing the solid model. If you delete an entity that has associated hard points, the hard points are either: Deleted along with the entity (if the hard points are not associated with any other entities). Detached from the deleted entity (if the hard points are associated with additional entities). You can define hard points on existing lines or areas. In both cases, you can define the location of hard points on such entities by: Picking (unavailable for models imported from IGES files). Specifying ratios (available for lines only). Specifying global X, Y and Z coordinates. To create hard points, use one of the methods listed in the following table. On an existing line On an existing area Main Menu> Preprocessor> Modeling> Create> Keypoints> Hard PT on line> Hard PT by ratio Main Menu> Preprocessor> Modeling> Create> Keypoints> Hard PT on line> Hard PT by coordinates Main Menu> Preprocessor> Modeling> Create> Keypoints> Hard PT on line> Hard PT by picking Main Menu> Preprocessor> Modeling> Create> Keypoints> Hard PT on line> Hard PT by coordinates Main Menu> Preprocessor> Modeling> Create> Keypoints> Hard PT on line> Hard PT by picking CivilFEM INTRO. Essential 80

81 5.4. Preprocessing Example To create the solid model, first define the keypoints. The number and the coordinates of the keypoints are the following. KP number Coordinates KP number Coordinates KP number Coordinates 1 15,0, ,15,0 11 0,30,0 2 15,0,0 7 0,15,0 12 0,30,15 3 0,0,0 8 0,15, ,15,15 4 0,0, ,30, ,15,0 5 15,15, ,30, ,30,0 KP 11 KP 10 KP 15 KP 12 KP 9 KP 7 KP 6 KP 14 KP 8 KP 5 KP 13 KP 3 KP 2 KP 4 KP 1 CivilFEM INTRO. Essential 81

82 5.4. Preprocessing To create the first KP: Main Menu > Preprocessor > Modeling > Create > Keypoints > In Active CS Enter the coordinates of KP number 1. Then, repeat with the other KPs. Enter the number and the coordinates of the KP Lines Definition Lines are mainly used to represent the edges of an object. As with keypoints, lines are defined within the currently active coordinate system. You do not always need to define all lines explicitly because the program will generate the necessary lines in many instances when an area or volume is defined. Lines are required if you want to generate line elements (such as beams) or to create areas from lines. 2. LINES There are many ways to create lines, as shown below. If you define areas or volumes, ANSYS will automatically generate any undefined lines with the curvature determined by the active CS. Keypoints must be defined in order to create lines. Create > Lines > Lines Create > Lines > Arcs Create > Lines > Splines Operate > Extrude CivilFEM INTRO. Essential 82

83 5.4. Preprocessing Example Once the KPs have been created, define the lines between those KPs. Main Menu > Preprocessor > Modeling > Create > Lines > Lines > Straight Line Pick or enter the KPs that define the line. Repeat with all of the KPs to define the lines. CivilFEM INTRO. Essential 83

84 5.4. Preprocessing Areas Definition 3. AREAS Creating areas using the bottom-up method requires the definition of keypoints or lines. If you define volumes, ANSYS will automatically generate any undefined areas and lines with the curvature determined by the active Coordinate System. Create > Areas > Arbitrary Operate > Extrude Volume Definition 4. VOLUMES Creating volumes using the bottom-up method require keypoints or areas to be already defined. Create > Volumes > Arbitrary Operate > Extrude CivilFEM INTRO. Essential 84

85 5.4. Preprocessing Example Finally, we create areas and volumes to completely define the geometry of the model. Main Menu > Preprocessor > Modeling > Create > Volumes > Arbitrary > Through KPs Enter the KPs numbers to define the first volume. Do the same with the KPs to define the second volume. Main Menu > Preprocessor > Modeling > Create > Areas > Arbitrary > Through KPs Enter the KPs numbers to define the first area: 5, 13, 14, 6. Repeat with the remaining KPs to define the second area. The second area is defined by the KPs 6, 14, 15, 10. CivilFEM INTRO. Essential 85

86 5.4. Preprocessing Once all the areas and volumes have been created, the geometry is the following: Another Useful Operation: Extrusion This option is used to quickly create volumes from existing areas (or areas from lines and lines from keypoints). If the area that is being extruded is meshed (or belongs to a meshed volume), the mesh will be used as a pattern for the mesh of the volume that is created. CivilFEM INTRO. Essential 86

87 5.4. Preprocessing There are four ways to extrude areas: Along Normal: Creates a volume by normal offsets of areas. By XYZ offset: Creates a volume by a general x-y-z offset. About Axis: Creates a volume by revolving areas about an axis. Along Lines: Creates a volume by dragging areas along a line or a set of adjoined lines. Follow these steps to extrude your mesh: 1. Mesh the area that is to be extruded (using MESH200 elements). 2. Select an appropriate 3-D element type (match the shape and number of nodes to the MESH200 element), and change the element attributes. CivilFEM INTRO. Essential 87

88 5.4. Preprocessing 3. Specify the desired number of element divisions in the extruded direction (NDIV argument). If using Extrude Along Lines, specify the number of element divisions on the drag path line(s) (NDIV argument). 4. Issue one of the following options (in this case Extrude by XYZ Offset): CivilFEM INTRO. Essential 88

89 5.4. Preprocessing Save Database and Resume Save Database and Resume It is good practice to save the database frequently because CivilFEM does NOT run automatic backups. The SAVE operation copies the database from memory to the files called database files. The easiest way to do a save is to click on Toolbar > SAVE Or use ~CFSAVE command To restore the database from the db file back into memory, use the RESUME operation. Toolbar > RESUME Or use ~CFRESUM command CivilFEM INTRO. Essential 89

90 5.4. Preprocessing The default file name for save (~CFSAVE) and resume (~CFRESUM) is jobname.cfdb, but you can choose a different name by using the Change Jobname (Utility menu> File> Change Jobname). The db file is simply a snapshot of what is in memory at the time the file is saved. CivilFEM database (.CFDB) and ANSYS database (.DB) files are created simultaneously. It is recomended to use ~CFRESUM and ~CFSAVE commands to resume and save ANSYS and CivilFEM databases simultaneously. When you save the database, CivilFEM also creates two more files:.dbb and.cfdbb. These files are the previous.db and.cfdb backup files. SAVE and RESUME commands will only operate on the ANSYS.DB database. It is therefore recommended to use the ~CFSAVE and ~CFRESUM commands, which operate on both databases. Example CivilFEM INTRO. Essential 90

91 5.4. Preprocessing Create Finite Element Model Create Finite Element Model Meshing is the process used to fill the solid model with nodes and elements to create the FEA model. There are three steps needed for meshing: Define element attributes Specify mesh controls Generate the mesh Element Attributes definition Before the mesh is created, the materials used must be defined, the element types selected from the library, and their properties identified (stress state, nonlinear behaviour, etc.). If needed, the Beam & Shell Properties (or real constants groups for some solid elements) must be defined as well. Each part of the model will need a different material or element type. Therefore, it is important to determine which attributes must to be assigned to the corresponding elements. CivilFEM INTRO. Essential 91

92 5.4. Preprocessing Element attributes are characteristics of the finite element model that must be established prior to meshing. They include: Element types: TYPE CivilFEM Beam & Shell Properties. Depending on the type of element they will generate: Real constants group: REAL Section: SECNUM (BEAM188 and BEAM189) Material: MAT Whenever you have multiple TYPEs, REALs (or SECNUMs), or MATs, you need to make sure that each element is assigned the proper attributes. There are three ways to do this: Assign attributes to the solid model entities before meshing Activate a global setting of MAT, TYPE, and REAL (or SECNUM) before meshing Modify element attributes after meshing If no assignments are made, CivilFEM uses default settings of MAT=1, TYPE=1, and REAL=1 (or SECNUM=1) for all elements in the model. Note, the current active TYPE, REAL, SECNUM and MAT dictate mesh operation. To activate a global setting of MAT, TYPE, and REAL (or SECNUM) before meshing: 1. Define all necessary element types, materials, and Beam&Shell Props. or real constant sets. 2. Then use the Element Attributes section of the MeshTool (Main Menu >Preprocessor >Meshing >MeshTool): Choose Global and press the SET button. Activate the desired combination of attributes in the Meshing Attributes dialog box. We refer to these as the active TYPE, REAL (or SECNUM), and MAT settings. 3. Mesh only those entities to which the above settings apply. CivilFEM INTRO. Essential 92

93 5.4. Preprocessing If you want to modify the attributes after meshing: Main Menu > Preprocessor > Modeling > Move/Modify > Elements > Modify Attrib Then pick the desired elements And in the subsequent dialog box, set attributes to All to current Pick the elements Select the attribute to be modified and enter the number of the new attribute Mesh Controls The fundamental premise of FEA is that as the number of elements (mesh density) is increased, the solution, in general, gets closer and closer to the true solution. However, the solution time and computer resources required also increase dramatically as you increase the number of elements. The objectives of the analysis usually dictate the mesh density. ANSYS provides many tools to control mesh density, both on a global and local level: Global controls SmartSizing Global element sizing Default sizing Local controls Keypoint sizing Line sizing Area sizing CivilFEM INTRO. Essential 93

94 5.4. Preprocessing SmartSizing determines element sizes by assigning divisions on all lines, taking into account the curvature of the line, its proximity to holes and other features, and element order. SmartSizing is off by default, but is recommended for free meshing. It does not affect mapped meshing. (Free meshing vs. mapped meshing will be discussed later.) To use SmartSizing: Bring up the MeshTool (Main Menu > Preprocessor > Meshing > MeshTool), turn on SmartSizing, and set the desired size level. Size level ranges from 1 (very fine) to 10 (very coarse). Defaults to 6. Then mesh all volumes (or all areas) at once, rather than one-byone. Default Sizing. If you don t specify any controls, ANSYS uses default sizing, which assigns minimum and maximum line divisions, aspect ratio, etc., based on element order. Keypoint, Line and Area Sizing. Element size controls keypoints, lines, or the interior of areas: Main Menu > Preprocessor > Meshing > MeshTool; under Size Controls, select [Set] for Keypts, Lines, or Areas Or Main Menu > Preprocessor > Meshing > Size Cntrls > ManualSize > Keypoints, Lines or Areas. CivilFEM INTRO. Essential 94

95 5.4. Preprocessing Default Sizing. If you don t specify any controls, ANSYS uses default sizing, which assigns minimum and maximum line divisions, aspect ratio, etc., based on element order. Keypoint, Line and Area Sizing. Element size controls keypoints, lines, or the interior of areas: Main Menu > Preprocessor > Meshing > MeshTool; under Size Controls, select [Set] for Keypts, Lines, or Areas Or Main Menu > Preprocessor > Meshing > Size Cntrls > ManualSize > Keypoints, Lines or Areas. Mesh generation Generating The Mesh is the final step in meshing. First save the database. Then press [Mesh] in the MeshTool. This brings up a picker. Press [Pick All] in the picker to indicate all entities. If a mesh is not acceptable, you can always re-mesh the model by following these steps: 1. Clear the mesh: The clear operation is the opposite of mesh: it removes nodes and elements. Use the [Clear] button on the MeshTool. 2. Specify new or different mesh controls. 3. Mesh again. CivilFEM INTRO. Essential 95

96 5.4. Preprocessing Other mesh options Refine Another meshing option is to refine the mesh in specific regions. Refine is available for all area elements and only tetrahedral volume elements. Easiest way is to use the MeshTool: First save the database. Then choose how you want to specify the region of refinement: at nodes, elements, keypoints, lines, or areas, and press the Refine button. Pick the entities at which you want the mesh to be refined. (Not required if you choose All Elems. ) Finally, choose the level of refinement. Level 1 (minimal refinement) is a good starting point. Sweep Sweep meshing is another option available for volume meshing. It is the process of meshing an existing volume by sweeping an area mesh. It is similar to mesh extrusion, except that the volume already exists in this case. Procedure: First define and activate a 3-D hexahedral solid element type, such as structural SOLID45 or SOLID95. Then bring up Mesh Tool and choose Hex/Wedge, Sweep, and how the source and target surfaces are identified: Auto Source/Target means that ANSYS and CivilFEM will automatically choose them based on the volume s topology. Pick Source/Target means that the user will choose them. Finally press the SWEEP button and follow prompt instructions from the picker. CivilFEM INTRO. Essential 96

97 5.4. Preprocessing Volume sweeping is useful if: You have imported a solid model that was created in another program, and you want to mesh it in ANSYS and CivilFEM. You want to create a hexahedral mesh for an irregular volume. In this case, you only have to break up the volume into a series of discrete sweepable regions. You either want to create a different mesh than the one that was created by one of the other extrusion methods or you forgot to create a mesh during one of those operations. If you do not mesh the source area prior to volume sweeping; ANSYS meshes it for you when you invoke the volume sweeper. The other extrusion methods require you to mesh the area yourself before you invoke them. If you do not, the other extrusion methods create the volume, but no area or volume mesh is generated. CivilFEM INTRO. Essential 97

98 5.4. Preprocessing Meshing Methods There are two main meshing methods: free and mapped. Free Mesh Has no element shape restrictions. The mesh does not follow any pattern. Suitable for complex shaped areas and volumes. Mapped Mesh Restricts element shapes to quadrilaterals for areas and hexahedral (bricks) for volumes. Typically has a regular pattern with obvious rows of elements. Suitable only for regular areas and volumes such as rectangles and bricks. Free Mesh Creating a free mesh is simple: Bring up the MeshTool and verify that free meshing is set. SmartSizing is generally recommended for free meshing, so activate it and specify a size level. Save the database. Then initiate the mesh by pressing the Mesh button. Press [Pick All] in the picker to choose all entities (recommended). CivilFEM INTRO. Essential 98

99 5.4. Preprocessing Mapped Mesh Creating a mapped mesh is not as easy as free meshing because the areas and volumes have to meet certain requirements: Area must contain either 3 or 4 lines (triangle or quadrilateral). Volume must contain either 4, 5, or 6 areas (tetrahedron, triangular prism, or hexahedron). Element divisions on opposite sides must match. For triangular areas or tetrahedral volumes, the number of element divisions must be even. In most cases, the model geometry is such that the areas have more than 4 sides and volumes have more that 6 sides. To convert these to regular shapes, you may need to do one or both of the following operations: Slice the areas (or volumes) into smaller, simpler shapes. Concatenate two or more lines (or areas) to reduce the total number of sides. SLICING Slicing can be accomplished with the Boolean divide operation. Remember that you can use the working plane, an area, or a line as the slicing tool. CivilFEM INTRO. Essential 99

100 5.4. Preprocessing CONCATENATION Concatenation creates a new line (for meshing purpose) that is a combination of two or more lines, thereby reducing the number of lines that surround the area. Use the LCCAT command or Main Menu > Preprocessor > Meshing > Concatenate > Lines, then pick the lines to be concatenated. For area concatenation, use ACCAT command or Main Menu > Preprocessor > Meshing > Concatenate > Areas. Concatenating these two lines makes this a 4-sided area You can also apply a concatenation by simply identifying the three or four corners of the area. In this case, ANSYS and CivilFEM internally generate the concatenation. - To do this, choose Quad shape and Map mesh in the Mesh Tool. - Then change 3/4 sided to pick corners. - Press the Mesh button, pick the area, and then pick the 3 or 4 corners that form the regular shape. Notes on concatenation: CivilFEM INTRO. Essential 100

101 5.4. Preprocessing If concatenations are present ANSYS and CivilFEM will not allow the extrusion operation. It is purely a meshing operation and therefore should be the last step before meshing, after all solid modelling operations. This is because the output entity obtained from a concatenation cannot be used in any subsequent solid modelling operation. You can undo a concatenation by deleting the line or area it produced. Concatenating areas (for mapped volume meshing) is generally much more complicated because you may also need to concatenate some lines. Lines are automatically concatenated only when two adjacent, 4- sided areas are concatenated. Example Once the geometry is totally defined, we generate the mesh. Element types and materials are the following: Main Menu >Preprocessor >Meshing >MeshTool Mat: Concrete ET: Solid45 Mat: Concrete ET: Plane42 Mat: Concrete ET: Shell63 Mat: Steel ET: Beam4 CivilFEM INTRO. Essential 101

102 5.4. Preprocessing First, we mesh the block. The element edge length is 1. Select the volumes to be meshed CivilFEM INTRO. Essential 102

103 5.4. Preprocessing Now we mesh the two areas. The element edge length is the same. Select the area to be meshed Select the area to be meshed CivilFEM INTRO. Essential 103

104 5.4. Preprocessing Finally we mesh the beams. Select the lines to be meshed Selection and Components If you have a large model, it is helpful to work with just a portion of the model data to apply loads, to speed up graphics displays, to review results selectively, and so on. Because all ANSYS and CivilFEM data are in a database, you can conveniently choose subsets of the data by selecting them. Selection Tools Selecting enables you to group subsets of nodes, elements, keypoints, lines, etc. so that you can work with just a handful of entities. The ANSYS and CivilFEM program uses a database to store all the data that you define during an analysis. The database design allows you to select only a portion of the data without destroying other data. CivilFEM INTRO. Essential 104

105 5.4. Preprocessing Selection Tools The selection Tools allows you to select a subset of entities and operate only on those entities. Most selecting tools are available in the Select Entities dialog box: Utility Menu > Select > Entities Entity to select Criterion by which to select Type of selection The GUI path is Utility Menu> Select> Entities. From the Select Entities dialog box the user can choose, among other things, the type of entities and the criteria by which the entities are selected: Criterion by which to select: By Num/Pick: based on entity numbers or by picking. Attached to: based on attached entities. For example, select all lines attached to the current subset of areas. By Location: based on X,Y,Z location. For example, select all nodes at X=2.5. X,Y,Z are interpreted in the active coordinate system. By Attributes: based on material number, real constant set number, etc. Different attributes are available for different entity types. Exterior: used to select entities lying on the exterior. By Results: used to select entities by results data. For example, nodal displacements. CivilFEM INTRO. Essential 105

106 5.4. Preprocessing Type of selection From Full: selects a subset from the full set of entities. Reselect: selects (again) a subset from the current subset. Also Select: adds another subset to the current subset. Unselect: deactivates a portion of the current subset. Invert: toggles the active and inactive subsets. Select None: deactivates the full set of entities. Select All: reactivates the full set of entities. From Full Reselect Also Select Unselect Invert Select None Select All After all desired operations are completed on the selected subset, it is recommended to reactivate the full set of entities. If all nodes and all elements are not active for a solution, the solver will issue a warning to that effect. The simplest way to reactivate the full set is to select everything : Utility Menu > Select > Everything You can also use the [Sele All] button in the Select Entities dialog box to reactivate each entity set separately. Selecting can also help the user during postprocessing. For instance, in POST1, you can select just a portion of your model to display or list the results. You should always use selecting to obtain meaningful results in POST1 when the model has discontinuities. Sometimes it is convenient to group portions of the model and give them recognizable names. These groupings may be components or assemblies. CivilFEM INTRO. Essential 106

107 5.4. Preprocessing Components A component consists of one type of entity: nodes, elements, keypoints, lines, areas or volumes. Another available operation is to assign a name to the selected subset by creating a component. The name can be used in dialog boxes or commands in place of entity numbers or the label ALL. A group of nodes, elements, keypoints, lines, areas, or volumes can be defined as a component. Only one entity type is associated with a component. Components can be selected or unselected. When you select a component, you are actually selecting all of the entities in that component. Assemblies An assembly may consist of any number of components and other assemblies (both of which must have been previously defined). Use the CMGRP command (Utility Menu> Select> Comp/Assembly> Create Assembly) to define an assembly. CivilFEM INTRO. Essential 107

108 5.4. Preprocessing Component Manager is used to Create, Display, List and Select Components and Assemblies. Utility Menu > Select > Component Manager Enter the name All of the currently selected entities will be included in the component, or you can select (pick) the desired entities at this step. CivilFEM INTRO. Essential 108

109 5.4. Preprocessing Example Now, create the elements of the struts. These elements will be created by direct generation, so first, select the nodes that will define these elements. Utility Menu > Select > Entities Select these two lines Once the nodes have been selected, define the element attributes and then create the element. Main menu > Preprocessor > Modeling > Create > Elements > Elem Attributes Main menu > Preprocessor > Modeling > Create > Elements > Auto Numbered > Thru Nodes CivilFEM INTRO. Essential 109

110 5.4. Preprocessing Select these nodes Utility Menu > Select > Everything And now the other strut. Select these two lines CivilFEM INTRO. Essential 110

111 5.4. Preprocessing Select these nodes If you select everything and plot the elements, you can see the complete finite element model. Utility Menu > Select > Everything Utility Menu > Plot > Elements CivilFEM INTRO. Essential 111

112 5.5. Solution 5.5 Solution The word loads in ANSYS and CivilFEM terminology includes boundary conditions and externally or internally applied forcing functions. 5.5 SOLUTION Loads and Boundary Conditions The solution step is where we apply loads and boundary conditions on the object and let the solver calculate the finite element solution. Loads are available both in the Solution and Preprocessor menus. CivilFEM INTRO. Essential 112

113 5.5. Solution Types of loads There are five categories of loads: DOF Constraints Concentrated Loads Surface Loads Body Loads Inertia Loads Specified DOF values, such as displacements in a stress analysis or temperatures in a thermal analysis. Point loads, such as forces or heat flow rates. Loads distributed over a surface, such as pressures or convections. Volumetric or field loads, such as temperatures (causing thermal expansion). Loads due to structural mass or inertia, such as gravity and rotational velocity. You can apply most loads either on the solid model (on keypoints, lines, and areas) or on the finite element model (on nodes and elements). For example, you can specify forces at a keypoint or at a node. Similarly, you can specify convections (and other surface loads) on lines and areas or on nodes and element faces. No matter how you specify the loads, the solver expects all loads to be in terms of the finite element model. Therefore, if you specify loads on the solid model, the program automatically transfers them to the nodes and elements at the beginning of solution. Solid-Model Loads Advantages: Solid-model loads are independent of the finite element mesh. Therefore, the element mesh can be changed without affecting the applied loads. This allows you to make mesh modifications and conduct mesh sensitivity studies without having to reapply loads each time. The solid model usually involves fewer entities than the finite element model. Therefore, selecting solid model entities and applying loads on them is much easier, especially with graphical picking. Disadvantages: Elements generated by ANSYS and CiviFEM meshing commands are in the currently active element coordinate system. Nodes generated by meshing commands use the global Cartesian coordinate system (by CivilFEM INTRO. Essential 113

114 5.5. Solution default). Therefore, the solid model and the finite element model may have different coordinate systems and loading directions. You cannot display all solid-model loads. You can apply loads either on the solid model or directly on the FEA model (nodes and elements). Solid model loads are easier to apply because there are fewer entities to pick. Moreover, solid model loads are independent of the mesh. You don t need to reapply the loads if you change the mesh. Pressure on line Pressures on element faces Solid model Constraint on line FEA model Constraints at nodes Force at keypoint Force at node Solid loads transference process Solid-model loads are automatically transferred to the finite element model at the beginning of solution. If you mix solid model loads with finite-element model loads, couplings, or constraint equations, you should be aware of the following possible conflicts: Transferred solid loads will replace nodal or element loads already present, regardless of the order in which the loads were input. Deleting solid model loads also deletes any corresponding finite element loads. Also loads and boundary conditions can be transferred to the finite element model before solution in this way: CivilFEM INTRO. Essential 114

115 5.5. Solution Plot and List Loads Verifying applied loads Plot the applied loads by activating load symbols: Utility Menu > PlotCtrls > Symbols Or list them: Utility Menu > List > Loads CivilFEM INTRO. Essential 115

116 5.5. Solution Example To apply the boundary conditions on the bottom surface of the block, select the nodes of that surface. Utility Menu > Select > Entities Main Menu > Solution > Define Loads > Apply > Structural > Displacement > on Nodes Enter the coordinates to the plane of nodes to be selected Select UX, UY and UZ directions Utility Menu > Select > Everything Plot > Elements CivilFEM INTRO. Essential 116

117 5.5. Solution You can apply a linearly varying surface load, such as hydrostatic pressure on a structure immersed in water: - GUI: Main Menu> Preprocessor> Loads> Define Loads> Settings> For Surface Ld> Gradient Main Menu> Solution> Define Loads> Settings> For Surface Ld> Gradient - Command: SFGRAD To create the gradient specification, you specify the type of load to be controlled (the Lab argument), the coordinate system and coordinate direction the slope is defined in (SLKCN and Sldir, respectively), the coordinate location where the value of the load (as specified on a subsequent surface load command) will be in effect (SLZER), and the slope (SLOPE). Now, apply all the loads. Hydrostatic Pressure First we have to select the elements where the pressure will be applied Utility Menu > Select > Entities CivilFEM INTRO. Essential 117

118 5.5. Solution Then, we define the pressure gradient to be applied Main Menu > Solution > Define Loads > Settings > For Surface Ld > Gradient And finally we apply the pressure on the selected elements Main Menu > Solution > Define Loads > Apply > Structural > Pressure > On Elements Enter the element face where the pressure is applied. CivilFEM INTRO. Essential 118

119 5.5. Solution Once this load has been applied, it is very important to delete the gradient before applying the rest of the loads. GUI: Main Menu> Preprocessor> Loads> Define Loads> Settings> For Surface Ld> Gradient Main Menu> Solution> Define Loads> Settings> For Surface Ld> Gradient Command: SFGRAD Self weight Utility Menu > Select > Everything Main Menu > Solution > Define Loads > Apply > Structural > Inertia > Gravity > Global Surface Load Main Menu > Solution > Define Loads > Apply > Structural > Pressure > On Elements The first step is to select the elements where the pressure will be applied. CivilFEM INTRO. Essential 119

120 5.5. Solution To select these elements, select the top area of the block, then the nodes located in this area, and the finally the elements that are attached to those nodes. Utility Menu > Select > Entities Now apply the pressure: Main Menu > Solution > Define Loads > Apply > Structural > Pressure > On Elements Enter the number of the face where the load is going to be applied Enter the value of the pressure Pressures are applied perpendicular to the element surfaces. Faces where the pressure will be applied are represented by number; this numbering depends on the element type. Information about face numbers can be found in element type help. In this example, the element type used for the terrain is SOLID45. This is a 3D solid element defined by eight nodes and six faces. The geometry, node CivilFEM INTRO. Essential 120

121 5.5. Solution locations, faces, and coordinate system for this element are shown in the following figure: So in this example, the face where the pressure has been applied is the number 6 (the top surface). The face numbering is always associated with the element coordinate system. In the example all the solid elements have their coordinate system parallel to the Global Cartesian (default orientation). Punctual Load Utility Menu > Select > Everything Utility Menu > Plot > Elements Main Menu > Solution > Define Loads > Apply > Structural > Force/Moment > On Keypoints Select the KP located on the corner of the shell (or enter the number of that KP) Select this KP CivilFEM INTRO. Essential 121

122 5.5. Solution Then enter the direction and the value of the force. This load will be transferred to the nodes in the solution process. Thermal Increment Utility Menu > Select > Everything Utility Menu > Plot > Elements Main Menu > Solution > Define Loads > Apply > Structural > Temperature > On Areas Select the area of the wall Select this area CivilFEM INTRO. Essential 122

123 5.5. Solution Enter the temperature You can verify this load: Utility menu > List > Loads > Body > On All Areas Solve The Model Solve Once the loads and boundary conditions have been applied, the next step is to solve the model. This can be done through the menu: Main Menu > Solution > Solve > Current LS Before you solve, you must select the type of analysis to be done. Main Menu > Solution > Analysis Type > New Analysis These different options of analysis will be explained in the following days. CivilFEM INTRO. Essential 123

124 5.5. Solution Example Select all the entities before solving the model. Utility Menu > Select >Everything Main Menu > Solution > Solve > Current LS Results File Results file When the model has been solved, the results file is created. CivilFEM results file (.RCV) is created simultaneously with ANSYS results file (.RST). A CivilFEM results file has a similar structure as an ANSYS results file. Load step number 1 in the.rst file corresponds to the load step 1 in the.rcv, which contains additional data calculated by CivilFEM for postprocessing (such as stress and strain in each section point, forces and moments for solid sections )..RCV file also contains the results of check and design processes. These results are stored in blocks called ALTERNATIVES. The additional data and results contained in the CivilFEM files are not considered for analysis in ANSYS. CivilFEM INTRO. Essential 124

125 5.5. Solution The name of the ANSYS results file depends on the analysis discipline: Jobname.RST for a structural analysis. Jobname.RTH for a thermal analysis. Jobname.RMG for a magnetic field analysis. CivilFEM will create a parallel results file: Jobname.RCV for a structural analysis. CivilFEM will not add new results to thermal or magnetic analyses. Therefore, to resume the results from a structural analysis, it is necessary to have the ANSYS RST file and the CivilFEM RCV file (RCV file does NOT substitute the RST file). CivilFEM INTRO. Essential 125

126 5.6. Postprocessing 5.6 Postprocessing Postprocessing refers to reviewing the results of an analysis. It is arguably the most important step in the analysis because the user can observe how the applied loads have affected the design or model, the quality finite element mesh, etc. Two postprocessors are available for reviewing the results: POST1, the general postprocessor and POST26, the time-history postprocessor. POST1 allows you to review the results over the entire model at specific load steps and substeps (or at specific time-points or frequencies). POST26 allows you to review the variation of a particular result item at specific points in the model with respect to time, frequency, or some other result item. In this essential training manual the only postprocessor that will be explained is the general postprocessor (POST1). The time-history postprocessor, POST26, is explained in the advanced training manual. The solution phase calculates two types of results data: Primary data consist of the degree-of-freedom solution calculated at each node: displacements in a structural analysis, temperatures in a thermal analysis, and magnetic potentials in a magnetic analysis. These are also known as nodal solution data. Derived data are those results calculated from the primary data, such as stresses and strains in a structural analysis, thermal gradients and fluxes in a thermal analysis, magnetic fluxes in a magnetic analysis, etc. They are typically calculated for each element and may be reported at any of the following locations: all nodes of each element, all integration points of each element, or the centroid of each element. Derived data are also known as element solution data, except when they are averaged at the nodes. In such cases, they become nodal solution data. To enter the ANSYS general postprocessor: Main Menu> General Postproc. To enter the CivilFEM Civil Engineering particular processor: Main Menu> Civil Postprocessor. CivilFEM INTRO. Essential 126

127 5.6. Postprocessing 5.6 POSTPROCESSING You can plot and list results such as reactions, stress, strain, etc. with ANSYS and forces and moments or results on cross sections with CivilFEM The first step is to read the results for each load step. Once the desired results data are loaded into the computer s memory, you can review them through graphics displays and tabular listings. In addition, you can map the results data onto a path. Graphics displays are perhaps the most effective way to review results. CivilFEM INTRO. Essential 127

128 5.6. Postprocessing Types of ANSYS Postprocessor Graphics You can display the following types of graphics with ANSYS postprocessor: Deformed Shape Displays Contour Displays Vector Displays Path Plots You can display the following types of graphics with ANSYS postprocessor: Deformed Shape Displays Contour Displays Vector Displays Path Plots CivilFEM INTRO. Essential 128

129 5.6. Postprocessing Vector Displays Vector displays use arrows to show the variation of both the magnitude and direction of a vector quantity in the model. Examples of vector quantities are displacement (U), rotation (ROT), magnetic vector potential (A), magnetic flux density (B), thermal flux (TF), thermal gradient (TG), fluid velocity (V), principal stresses (S), etc. To produce a vector display, use the following: Main Menu > General Postproc > Plot Results > Vector Plot Path Plots These are graphs that show the variation of a quantity along a predefined path through the model. To produce a path plot, perform these tasks: Define a path. Main Menu > General Postproc > Path Operations > Define Path > By Nodes, On Working Plane or By Location Map data onto the path. General Postproc > Path Operations > Map onto Path CivilFEM INTRO. Essential 129

130 5.6. Postprocessing Plot the Data. Main Menu > General Postproc > Path Operations > Plot Path Item > On Graph. Main Menu > General Postproc > Path Operations > Plot Path Item > On Geometry. Note: Path operations are only applicable for nodes and elements results and therefore, not for cross section and shell vertex results. CivilFEM Postprocessor With the CivilFEM postprocessor you can display forces and moments graphics and section results. To display these graphs, use CivilFEM entities (Beam & Shell Properties must be defined). Main Menu > Civil Postprocessor > Beam Utilities > Graph Results Main Menu > Civil Postprocessor > Shell Utilities > Graph Results These graphics and section results are only available if the model contains CivilFEM entities. Beam and Shell Properties or Solid Sections, must be used. With CivilFEM, axial and shear forces and torsion and bending moments can be displayed or listed. CivilFEM INTRO. Essential 130

131 5.6. Postprocessing Forces and Moments in Beam Elements Main Menu >Civil Postprocessor > Beam Utilities > Graph Results > Forces & Moments In beam elements, axial and shear forces and also bending moments can either be plotted or listed. Graph results are plotted in a window similar to any other ANSYS result. CivilFEM INTRO. Essential 131

132 5.6. Postprocessing List Forces and Moments in Beam Elements Main Menu >Civil Postprocessor > Beam Utilities > Graph Results > Forces & Moments Listed results are exported to a HTML or ASCII file. The user can select the data that are listed. An HTML file is automatically created. CivilFEM also can display stresses and strains results in tessella sections and points. CivilFEM INTRO. Essential 132

133 5.6. Postprocessing Stresses and Forces in Cross Section Main Menu >Civil Postprocessor > Beam Utilities > Graph Results > Section Results In CivilFEM it is necessary to create and assign cross sections as well as real constants to beam elements in order to calculate elastic normal stresses in cross sections. The forces applied on these cross sections are also listed. RESULTS SX SY SZ SXY SYZ SZX EPX EPY EPZ EPXY EPYZ EPZX DESCRIPTION Represents stress in the X direction of the section. Represents stress in the Y direction of the section. Represents stress in the Z direction of the section. Represents XY tangential stress of the section. Represents YZ tangential stress of the section. Represents ZX tangential stress of the section. Represents elastic strain in the X direction of the section. Represents elastic strain in the Y direction of the section. Represents elastic strain in the Z direction of the section. Represents XY tangential elastic strain of the section. Represents YZ tangential elastic strain of the section. Represents ZX tangential elastic strain of the section. CivilFEM INTRO. Essential 133

134 5.6. Postprocessing Forces are always listed. Stresses can be plotted in tessella or in points. Section Data Tessella results Section Data Points results CivilFEM INTRO. Essential 134

135 5.6. Postprocessing Forces and Moments in Shell Elements Main Menu >Civil Postprocessor > Shell Utilities > Graph Results > Forces & Moments Following the same procedure as for beams, forces and moments can be plotted or listed for shell elements as well. Stress & Strain in Shell Elements Main Menu >Civil Postprocessor > Shell Utilities > Graph Results > Stress & Strain Stresses and strains can be plotted for top and bottom fibers. CivilFEM INTRO. Essential 135

136 5.6. Postprocessing The results are plotted in the window or listed in a HTML or ASCII file. Stresses and Forces in Solid Section Main Menu >Civil Postprocessor > Beam Utilities > Graph Results > Section Results When a solid section is captured from a solid model, we can also get results from it. For this situation, the forces are obtained by integrating the stresses that CivilFEM gets from ANSYS. CivilFEM INTRO. Essential 136

137 5.6. Postprocessing The same window as for cross sections is displayed, but the method to obtain the results is different. More results can be plotted Example First, read the results and then plot the UY displacement. Main Menu > Civil Postprocessor > Read Results > By Load Step Main Menu > General Postprocessor > Plot Results > Contour Plot > Nodal Solu CivilFEM INTRO. Essential 137

138 CivilFEM INTRO. Essential Postprocessing

139 5.6. Postprocessing Next, plot the Shell Bending Moment in the Y direction. Main Menu > Civil Postprocessor > Shell Utilities > Graph Results > Forces & Moments Finally, plot the Beam Bending Moment in the Z direction. Main Menu > Civil Postprocessor > Beam Utilities >Graph Results > Forces & Moments CivilFEM INTRO. Essential 139

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141 5.6. Postprocessing 6 Importing Models CivilFEM INTRO. Essential 141

142

143 6.1. Introduction 6.1 Introduction 6.1 Introduction It is possible to import into CivilFEM models created from other sources: DXF geometry. ASCII Grid and LiDAR terrain definitions. SAP2000 Finite Element model. ROBOT Finite Element model. The import Utility can be accessed from the Windows Start Menu (inside the CiviFEM group) or from the Civil Preprocessor menu. Once the importing options have been specified, a name for the Output file (that will be generated for ANSYS) must be selected and will be created by clicking the "Generate Output File" button. This file can be run in ANSYS. If the importing utility has been launched from inside ANSYS, (Civil Preprocessor > Utilities > Import from ) the "Run" button will be shown to allow the model to be created directly (it is recommended to have previously executed ~CFCLEAR command) The utility keeps the last files paths to make it easier to use. You can erase these paths by pressing the button "Clear File Names". The View" buttons are for viewing the respective input/output files. CivilFEM INTRO. Essential 143

144 6.1. Introduction 6.2 DXF After selecting the DXF geometry file, CivilFEM will read the existent layers in the model and will allow the user to select layers to be imported: The entities that will be read from the DXF file are the following: 3DFACE, ARC, CIRCLE, LINE, LWPOLYLINE, POINT, POLYLINE (POLYFACE MESH, 3D POLYLINE, 3D POLYGON MESH), SOLID, TEXT, TRACE. Entities that are not included in this list may generate a warning message. Despite the message, the model will be created, ignoring those entities that cannot be imported. CivilFEM INTRO. Essential 144

145 6.1. Introduction 6.3 ASCII Grid/LiDAR First, the LiDAR geometry file to be imported must be selected. Then, it is possible to specify a coordinates range used to import only a part of the model. LiDAR files may contain a great amount of information that is not always necessary for model generation. It is possible to downsample the resolution of the model by using just one point for every n points of the original model. 6.4 SAP2000 (version 7.10) It is necessary to generate several input files based on the geometry the user wants to import. To do this in SAP2000, it is necessary to open the menu: "Display > Show Import Tables > Geometry Data" and generate a file for nodes, another for beams, and so on. In the corresponding tab of "CivilFEM Import Utility" the created files will be selected. CivilFEM INTRO. Essential 145

146 6.1. Introduction 6.5 ROBOT MILLENIUM 97 For this program it is necessary to generate only one input file with geometry that will be exported. To do this, in Robot Millenium, the file must be saved in text format, with extension "*.STR" (instead of the extension "*.RTD" of Robot). In the corresponding tab of "CivilFEM Import Utility" the created file must be selected: CivilFEM INTRO. Essential 146

147 6.1. Introduction 7 Coordinate System CivilFEM INTRO. Essential 147

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149 7.1 Coordinate Systems 7.1. Coordinate Systems CivilFEM uses several types of coordinate systems, each used for a different purpose: Global and local coordinate systems are used to locate geometry items (nodes, keypoints, etc.) in space. The display coordinate system determines the system in which geometry items are listed or displayed. The nodal coordinate system defines the degree of freedom directions at each node and the orientation of nodal results data. The element coordinate system determines the orientation of material properties and element results data. The results coordinate system is used to transform nodal or element results data to a particular coordinate system for listings, displays, or general postprocessing operations (POST1). 7.1 Coordinate Systems In CivilFEM there are different coordinate systems: Global Coordinate System Local Coordinate System Element Coordinate System (ESYS) Nodal Coordinate System Results Coordinate System (RSYS) Display Coordinate System (DSYS) CivilFEM INTRO. Essential 149

150 7.2. Global Coordinate System 7.2 Global Coordinate System A global coordinate system can be thought of as an absolute reference frame. ANSYS provides three predefined global systems: Cartesian, cylindrical, and spherical. All three of these systems are right-handed. They are identified by their coordinate system (C.S.) numbers: 0 for Cartesian, 1 for cylindrical and 2 for spherical. a) Cartesian (X, Y, Z components) coordinate system 0 (C.S.0) b) Cylindrical (R, θ, Z components) coordinate system 1 (C.S.1) c) Spherical (R, θ, φ components) coordinate system 2 (C.S.2) d) Cylindrical (R, θ, Y components) coordinate system 5 (C.S.5) (a) (b) (c) (d) 7.2 Global Coordinate System (CSYS) The global reference system for the model. May be Cartesian (system 0), cylindrical (1), or spherical (2). By default, the Active Coordinate System is the Global Cartesian. You can change it to (Utility Menu > WorkPlane > Change Active CS to) Global Cartesian Global Cylindrical Global Spherical Working plane User-defined local coordinate system The command needed to change the global coordinate system is CSYS. CivilFEM INTRO. Essential 150

151 7.3. Local Coordinate System 7.3 Local Coordinate System 7.3 Local Coordinate System In many cases, it may be necessary to establish your own coordinate system which has an origin offset from the global origin, or an orientation that differs from the predefined global systems. Local coordinate systems can be created in the following ways: Utility Menu> WorkPlane> Local Coordinate Systems> Create Local CS> At Specified Loc. Utility Menu> WorkPlane> Local Coordinate Systems> Create Local CS> By 3 Nodes. Utility Menu> WorkPlane> Local Coordinate Systems> Create Local CS> By 3 Keypoints. Utility Menu> WorkPlane> Local Coordinate Systems> Create Local CS> At WP Origin. Define the local system in terms of the active coordinate system with the CLOCAL command. CivilFEM INTRO. Essential 151

152 7.4. Element Coordinate System When a local coordinate system is defined, it becomes the active coordinate system. As you create a local system, you assign it a CSYS identification number (which must be 11 or greater). You can create (or delete) local coordinate systems in any phase of your ANSYS session. To delete a local system, use the following method: Utility Menu> WorkPlane> Local Coordinate Systems> Delete Local CS Local coordinate systems can be Cartesian, Cylindrical or Spherical. 7.4 Element Coordinate System 7.4 Element Coordinate System (ESYS) Every element has its own coordinate system that determines the direction of orthotropic material properties, applied pressures, and results (such as stresses and strains) for that element. All element coordinate systems are right-handed orthogonal systems. The default ESYS orientation is described in the Help document for each element type. Many element types have key options that allow you to change the default element coordinate system orientation. For area and volume elements, you can also change the orientation to align the element coordinate system with a previously defined local system by using one of the following methods: To change the default ESYS, it is necessary to align it with a specified local coordinate system (CSYS 11 or greater). CivilFEM INTRO. Essential 152

153 The procedure is as follows: 7.4. Element Coordinate System 1. Define a local coordinate system with the appropriate orientation. Location is generally arbitrary. Utility Menu > WorkPlane > Local Coordinate Systems > Create Local CS 2. Select the desired elements. 3. Modify the ESYS attribute of all selected elements to the local system number defined in step 1. Preprocessor> Modeling> Move/Modify > Elements> Modify Attrib Or EMODIF command (e.g, emodif,all,esys,11) 4. Reactivate all elements and switch back to previous coordinate system (CSYS). Beam elements coordinate systems have the X axis always parallel to the beam, and the orientation of the Z-Y axis can only be changed by creating a third node (orientation node) or using the THETA angle of the Real Constants (not all elements have this option). Main Menu> Preprocessor> Modeling> Create> Elements> Elem Attributes Main Menu> Preprocessor> Meshing> Mesh Attributes> Default Attribs The default orientations for most elements' coordinate systems fit the following patterns: Line elements have the element X-axis directed from their node I toward their node J. Y-axis parallel to the global X-Y plane. CivilFEM INTRO. Essential 153

154 7.5. Nodal Coordinate System Shell elements: - element X from node I to node J - element Y perpendicular to element X in the plane of the element - element Z normal to X-Y by right-hand rule For 2-D and 3-D solid elements, the element coordinate system is usually parallel to the global Cartesian system. 7.5 Nodal Coordinate System 7.5 Nodal Coordinate System While global and local coordinate systems locate geometry items, the nodal coordinate system orients the degree of freedom directions at each node. Each node has its own nodal coordinate system, which by default, is parallel to global Cartesian. You can rotate the nodal coordinate system at any node to a desired orientation using one of the following methods: Main Menu> Preprocessor> Modeling> Move/Modify> Rotate Node CS> To Active CS Main Menu> Preprocessor> Modeling> Move/Modify> Rotate Node CS> By Angles Main Menu> Preprocessor> Modeling> Move/Modify> Rotate Node CS> By Vectors CivilFEM INTRO. Essential 154

155 7.6. Results Coordinate System 7.6 Results Coordinate System 7.6 Results Coordinate System (RSYS) Results data are calculated during solution and consist of displacements, stresses, strains, etc. These data are stored in the database and in the results file in either the nodal coordinate system or the element coordinate system. However, results data are generally rotated into the active results coordinate system (which is by default the global Cartesian system) for displays, listings, and element table data storage. It is possible to change the active results coordinate system to another system: Main Menu> General Postproc> Options for Output CivilFEM INTRO. Essential 155

156 7.7. Display Coordinate System 7.7 Display Coordinate System 7.7 Display Coordinate System (DSYS) By default, a listing of nodes or keypoints always shows their global Cartesian coordinates, even if they were defined in a different coordinate system. You can change the display coordinate system used in such listings by one of the following methods: Utility Menu> WorkPlane> Change Display CS to> Global Cartesian Utility Menu> WorkPlane> Change Display CS to> Global Cylindrical Utility Menu> WorkPlane> Change Display CS to> Global Spherical Utility Menu> WorkPlane> Change Display CS to> Specified Coord Sys Changing the display coordinate system will also affect your graphical displays. CivilFEM INTRO. Essential 156

157 8 Element types CivilFEM INTRO. Essential 157

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159 8.1 Mesh 200 elements 8.1. Mesh 200 elements 8.1 Mesh 200 MESH200 is a mesh-only element, contributing nothing to the solution. This element can be used for some operations, for example: Multistep meshing operations, such as extrusion. Temporary storage of elements when the physics analysis has not yet been specified. Meshing an area before importing it to a CivilFEM cross section. MESH200 may be used in conjunction with any other element types. After it is no longer needed, it can be deleted or left in place. Its presence will not affect solution results. The element is defined by two to twenty nodes, depending on the desired shape of the element. It has no degrees of freedom, material properties, beam & shell properties, or loadings. CivilFEM INTRO. Essential 159

160 8.2. Surface elements 8.2 Surface elements 8.2 Surface elements How would you apply a pressure load, that is: tangential to the surface, such as a shear load? spatially varying over the surface, such as a bolt load? oriented at an angle to the surface, such as ice load on a rooftop? Surface effect elements provide an effective way to do this. Characteristics: They overlay the surface of an underlying mesh like a skin. They act as a conduit for surface loads. Creating them is very easy: Select nodes on the surface of interest and at least the elements attached to them. Activate the appropriate element type. Issue ESURF (or Preprocessor > Create > Elements > Surf / Contact > Surf Effect ). Select all nodes. CivilFEM INTRO. Essential 160

161 8.2. Surface elements Available for both 2-D and 3-D models: SURF151 & 153 are line elements (thermal and structural) meant for edges of 2D models. SURF152 & 154 are area elements (thermal and structural) meant for surfaces of 3D models. SURF156 are 3D line elements (structural) meant for edges of 3D models. We will discuss only SURF154 in this section, but the same concepts can be applied to the other elements. SURF154 as depicted in the Elements Reference manual CivilFEM INTRO. Essential 161

162 8.2. Surface elements SURF154 uses different element face numbers to accept different types of loads. The face number is a field in the "Apply PRES on elems" dialog (Solution > Define Loads > Apply > Structural > Pressures > On Elements), as shown below. The orientation of the pressure depends on which element face is used. Face 1: Normal pressure. Positive value acts into the element (along element -Z). Faces 2 & 3: Tangential pressures, along element X & Y respectively. CivilFEM INTRO. Essential 162

163 8.2. Surface elements Face 4: Normal pressure, tapered. Magnitude = P 1 + X g P 2 + Y g P 3 + Z g P 4 P 1 -P 4 are specified VAL1-VAL4 on SFE command. X g,y g, Z g are the global Cartesian locations of the element's integration points. P 2,P 3,P 4 are the slopes in global X,Y,Z respectively and default to P 1 if left blank. Positive value acts into the element (along element -Z). P 2 P 1 X g =0 X g For example, to apply a tapered pressure of 200 to 1000 in the global X direction, with X values ranging from -2 to +2: Slope P 2 = ( )/4 = 200; P 3 = 0; P 4 = 0 P 1 is the value at X g =0, calculated as P 1 = 2(200) = 600 sfe,eflat,4,pres,,600,200,0,0 CivilFEM INTRO. Essential 163

164 8.2. Surface elements Face 5 Vector-oriented pressure of magnitude P 1. Direction = P X P Y P Z 2 g g P P P g P 2,P 3,P 4 now represent the direction cosines of the vector and have no effect on the magnitude. Example: sfe,eflat,5,pres,,1000,-1,-1,0 defines a pressure at angle of 45 in the X-Y plane. The magnitude of vector-oriented pressure also depends on KEYOPT(11). KEYOPT(11)=0 (default) and 1 applies pressure on the projected area of surface elements. Useful for bolt loading (or pin loading). Example: sfe,ecurv,5,pres,,1000,0,-1,0 defines a bolt load on the curved surface, as shown by a POST1 contour plot below. CivilFEM INTRO. Essential 164

165 8.2. Surface elements KEYOPT(11)=2 applies pressure on the full area. Useful for inclined surfaces (such as a roof top) or wind loads. Example: sfe,eslope,5,pres,,1000,0,-1,0 defines uniform, full pressure on all faces of an inclined surface, as shown below. Surface Elements Example The aim of this simple example is to become familiar with surface elements. First, the surface and solid elements must be selected from ANSYS library. Main Menu> Preprocessor> Element type> Add/Edit/Delete Elements to be selected: 3D Structural154 (1) and Solid45 (2) Second, the material for the model is selected from CivilFEM material library. CivilFEM INTRO. Essential 165

166 8.2. Surface elements Main Menu> Civil Preprocessor> Materials Material to be selected: Concrete C35/45 Then, the model geometry is created: Keypoints and Volume through KPs KP X Y Z Main Menu> Preprocessor> Modeling> Create> Keypoints> In Active CS - Main Menu> Preprocessor> Modeling> Create> Volumes> Arbitrary> Through KPs CivilFEM INTRO. Essential 166

167 8.2. Surface elements Finally, generate the mesh (Main Menu> Preprocessor> Meshing> Mesh Tool): First, change the attributes: select the solid45 element CivilFEM INTRO. Essential 167

168 8.2. Surface elements Second, enter the number of line divisions: CivilFEM INTRO. Essential 168

169 8.2. Surface elements Third, select Hex and Mapped mesh and select the volume (the number of divisions in opposite lines must be the same). Finally, generate the mesh. CivilFEM INTRO. Essential 169

170 8.2. Surface elements Now a tangential pressure in Y direction will be applied to elements with Z=0 coordinate. First, select the nodes located at Z=0 (Utility menu> Select Entities > Nodes by location) Second, change the element attributes (Main Menu> Preprocessor> Modeling> Create> Elements> Elem Attributes) CivilFEM INTRO. Essential 170

171 8.2. Surface elements Then, create the surf elements (Main Menu> Preprocessor> Modeling> Create> Elements> Surf/Contact> Surf Effect> General Surface> No extra Node) Finally, apply the pressure of 1000 Pa in the Y direction: Select the elements by the number of element. (number 1) (Utility Menu> Select> Entities > Elements by attributes> Element type number) Apply the pressure (Main Menu> Solution> Define Loads> Apply> Structural> Pressure> On elements: Pick all). The Face number must be number 3; this indicates a tangential pressure in the Y direction. CivilFEM INTRO. Essential 171

172 8.2. Surface elements Change the symbols to arrows for the applied loads. (Utility Menu > PlotCtrls > Symbols) Change Surface Load Symbols to Tan-Y Pressures Choose Arrows CivilFEM INTRO. Essential 172

173 8.2. Surface elements For applying a horizontal pressure on the sloped face, follow the steps below: Select everything with the selection tools. (Utility Menu> Select> Everything) Then select the lateral area and finally the nodes attached to this area (Utility Menu> Select> Entities ). Confirm the element type selected is the surf element (element type number 1). This can be done by looking at the bottom of the GUI window. If not, change it (Main Menu> Modeling> Create> Elements> Elements Attributes). CivilFEM INTRO. Essential 173

174 8.2. Surface elements Then, create the surface elements (Main Menu> Preprocessor> Modeling> Create> Elements> Surf/Contact> Surf Effect> General Surface> No extra Node). Finally, select these created elements and apply the pressure of 1000 Pa in the X direction. (Main Menu> Solution> Define Loads> Apply> Structural> Pressure> On elements: Pick all) The load key indicates the way to apply the load These values indicate the direction of the load vector CivilFEM INTRO. Essential 174

175 8.3. Contact Elements The KEYOPTION 11 is 0 by default, so the pressure is applied on the projected area. If the pressure is to be applied on the full area, the KEYOPTION 11 in element type options is required to be changed when the SURF154 element is defined: 8.3 Contact Elements CivilFEM INTRO. Essential 175

176 8.3. Contact Elements 8.3 Contact elements In problems involving contact between two boundaries. TARGE element CONTAC element For rigid-flexible contact TARGET is the rigid surface and CONTAC is the deformable surface. For flexible-flexible contact both are deformable surfaces. 2D: TARGE169 with CONTAC171, CONTAC172, CONTAC175 3D: TARGE170 with CONTAC173, CONTAC174, CONTAC175, CONTAC176, CONTAC177 Real constant: Target and contact elements that make up a contact pair, are associated with the same real constant set. Different contact pairs must be defined by a different real constant set. The faces must be orientated with the normal direction opposite to the other one. Properties of contact surface can be defined with KEYOPT: Contact Algorithm Convergence parameters Behavior of contact surface CivilFEM INTRO. Essential 176

177 9 CivilFEM Materials CivilFEM INTRO. Essential 177

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179 9.1. CivilFEM and ANSYS Materials Coupling 9.1 CivilFEM and ANSYS Materials Coupling Material properties defined by CivilFEM include ANSYS standard properties as well as other properties necessary for CivilFEM specific calculations, such as properties related to codes: characteristics strengths, yield strengths, reduction coefficients, etc. 9.1 CivilFEM and ANSYS Materials Coupling CivilFEM materials are linked to those in ANSYS so that the number identifying the CivilFEM material corresponds to the number of the material in ANSYS. The definition of a material in CivilFEM implies the automatic definition of the ANSYS material properties and the data required for CivilFEM postprocess. When deleting or modifying a material with CivilFEM commands, the corresponding ANSYS material is also deleted or modified. It is not recommended to define nor delete the material properties using ANSYS, as CivilFEM material properties will not be defined or modified. CivilFEM INTRO. Essential 179

180 9.2 Materials definition 9.2. Materials definition 9.2 Materials definition Define materials by the following this menu path: Main Menu > Civil Preprocessor > Materials Some materials in CivilFEM are time dependent CivilFEM material definition (see CFMP command in CivilFEM Help) is achieved by selecting one of the materials included in its libraries. CivilFEM material library defines the following material types: Structural Steel Concrete Reinforcing Steel Prestressing Steel (*) Soils (*) Rocks (*) When selecting a material from the library all properties are automatically defined (*) Described in the Training for the Specialized Modules CivilFEM INTRO. Essential 180

181 9.2. Materials definition The material properties are divided into different groups of properties. General properties: common for all materials (number, reference, type, properties for elastic analysis,...) Analysis and design diagrams Material properties: Specific for steel, concrete, etc. Code properties: Specific for the code selected in the configuration menu, etc. FLAC3D properties: Only for exporting the model to FLAC 3D CivilFEM material properties are time dependent. This dependency is controlled by a global variable called active time (see ACTTIME command). This time is common to all materials and its value is fixed by the user in each instant. CivilFEM active time may or may not coincide with ANSYS time (ANSYS TIME command). On the other hand, each CivilFEM material contains the material s activation time and controls when the materials are initially activiated. Once active time and activation time are established, those materials whose activation time is the same or less than the active time will be active. Those elements of a section whose material is inactive do not exist to any effect (either in CivilFEM or in ANSYS). The age of each material is calculated for each instant from the active time (ActTime) and activation instant values: MatAge (Imat) = ActTime TmAct (Imat) Where: MatAge: Material Age ActTime: Active Time TmAct: Material s activation time Imat: Material taken into account This age allows the calculation of any property of the material in the considered instant by interpolation of the respective time dependent vectors. CivilFEM INTRO. Essential 181

182 9.2. Materials definition Material activation time Material Age = ActTime - TAct Calculation time When a material is defined, it is labeled with a reference associated with the chosen library material. The user can modify all of the properties which are not associated to the library. In order to modify the data associated to a library reference, the material must lose that reference and become labeled as User Def. CivilFEM INTRO. Essential 182

183 9.3. Structural Steel Material Properties 9.3 Structural Steel Material Properties General Properties 9.3 Structural Steel Material Properties General Properties All CivilFEM material properties may be modified if the User Def option is activated. General Properties are divided into: General properties Type Time Mechanical properties Cost Material name User Def option The command ~CFMP defines Structural Steel Material Properties in CivilFEM and ANSYS. It can be used with one of the options below: From Library: Data associated with a library reference. User defined: The material loses its library reference and the user can modify all the properties. CivilFEM INTRO. Essential 183

184 Analysis and Design Diagrams Analysis Diagram 9.3. Structural Steel Material Properties Analysis Diagram is the stress-strain diagram used for the structural analysis of the model. If the option User Def is activated, the user will be able to add or delete diagram points. Code dependent stressstrain diagrams exist for different material thicknesses. In addition, the diagram may be displayed in tension, compression or tension and compression. Type of diagram Material thickness Diagram points Type of plot Non-Linear Behavior Design Diagram Design Diagram is the stress-strain diagram used for the section s analysis. If the option User Def is activated, the user will be able to add or delete diagram points. Code dependent stressstrain diagrams exist for the different material thicknesses. In addition, the diagram may be displayed in tension, compression or tension and compression. It is possible to modify the diagrams by previously changing the field Type to 0: User Defined. Depending on the type of diagram, different non-linear behaviours can be selected (KPLA property). CivilFEM INTRO. Essential 184

185 9.3. Structural Steel Material Properties Depending on the active code, the material properties may depend on the thickness of the steel plate. The variation of the properties that depend on the thickness can be seen by selecting the thickness range on the bottom buttons. Steel Properties The material type window will vary according to the selected material and active code. Steel Properties Steel properties are properties related to the steel material only. If the option User Def is selected, the user will be able to change the material thickness as well as the modulus of elasticity. Steel properties include: Thickness dependent properties Linear structural properties ANSYS plastic behavior Strain limits Thickness definition Strain limits Code Properties The code window will vary according to the selected material and active code. CivilFEM INTRO. Essential 185

186 9.4. Concrete Material Properties Code Properties Properties related to the active steel code. Safety factors according to code Mechanical properties 9.4 Concrete Material Properties General Properties 9.4 Concrete Material Properties You can select one of the materials from the library and all the properties will be automatically defined. You can also modify all the properties by the User Def option. Define material properties from library Actual calculation time CivilFEM INTRO. Essential 186

187 9.4. Concrete Material Properties User Defined: You can define a material from the library and then modify it, changing its reference to User Def. Material Birth Time After changing its properties, you can save the material into the user material library. Analysis Diagram Analysis Diagram The analysis diagram is the stress-strain curve that will be used by ANSYS for the structural analysis of the model. It is possible to define the real stress-strain analysis diagrams of the materials using the pre-established for the active code or to modify these diagrams by adding or deleting points with the option user defined. Non-Linear Behavior One stress-strain curve for each age CivilFEM INTRO. Essential 187

188 9.4. Concrete Material Properties Design Diagram Design Diagram The design diagram is the stress-strain curve that is used by CivilFEM for section s check and design. Choose the stressstrain diagram type or define it by adding or deleting points. Concrete properties and code properties Concrete properties and code properties It is possible to add, delete or modify the existing ages of the material. All material properties are automatically calculated for the additional ages. Age dependent properties With time dependent materials, the user has the option to plot the evolution of certain properties through time by clicking with the right mouse button on the name of the property: CivilFEM INTRO. Essential 188

189 CivilFEM INTRO. Essential Concrete Material Properties

190 9.5. Reinforcing Steel Material Properties 9.5 Reinforcing Steel Material Properties The ~CFMP command defines all reinforcing steel material properties including the properties necessary to carry out an ANSYS analysis. 9.5 Reinforcing Steel Material Properties You can select a type of reinforcing steel from the library of materials and all the properties will automatically defined. You can also modify all of the properties by the User Def option. Define material properties from library: User Defined: You can define a material from the library and then modify it, changing its reference to User Def. After changing its properties, you can save the material into the user material library. CivilFEM INTRO. Essential 190

191 9.6 User Material Library 9.6. User Material Library After modifying a material, it can be saved for future sessions of CivilFEM. To do this, press the Save button on the material browser window. The name of the file where the material will be stored must be specified in the Database FileName field. If the file does not exist, it will be created, and if it already exists, the material will be added to the file. The name of the file will be the name of the folder that will appear inside the USER group of materials, and it will contain all the materials stored in it. To use the saved materials in a different computer, it is only necessary to copy the file or files that contain the materials to the respective folder on the other computer. 9.6 User Material Library It is possible to add user materials into the CivilFEM material library by: Selecting a material from the library Modifying its properties (User Def) Storing it in a file named by the user The name of the file to be created must be specified CivilFEM INTRO. Essential 191

192 9.6. User Material Library By default, the user material file will have the jobname. The extension of this file is.ump and it is stored in the following folder: %AppData%\CivilFEM\MatUserLib Where %AppData% is the System Application Data folder. For example: C:\Documents and Settings\User\Application Data The material properties are read and listed in the active unit system and code. CivilFEM INTRO. Essential 192

193 9.6. User Material Library To delete a saved material, select the material and press the button Delete material/file. To delete a whole file, all of the materials it contains must be deleted first. Once it is empty it is possible to delete it by selecting it and pressing the Delete material/file. CivilFEM INTRO. Essential 193

194 9.7. List of Materials 9.7 List of Materials 9.7 List of materials The properties of the materials defined in CivilFEM can be listed in ASCII or HTML. There are 2 types of listings: Short list Detailed list CivilFEM INTRO. Essential 194

195 10 CivilFEM Cross Sections CivilFEM INTRO. Essential 195

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197 10.1 Cross Section concept Cross Section concept 10.1 Cross Section concept This concept refers to a unique cross section, as commonly understood in engineering. There are many ways of defining cross sections with CivilFEM using the cross section explorer. Main Menu> Civil Preprocessor> Cross Section In this window we can see a list of all the defined cross sections 10.2 Steel Cross Sections 10.2 Steel Cross Sections A steel cross can be defined in five different ways: Library of hot rolled shapes Steel beams by dimensions Steel sections by plates Section merge Capture 2D mesh CivilFEM INTRO. Essential 197

198 10.2. Steel Cross Sections Hot Rolled Shapes Library To select the desired section, the user must find the section in the shapes library, located in the left side of the window. This library contains all the shapes classified in CivilFEM. Hot Rolled Shapes Library Search option Apply+Exit Section dimensions Add shapes into the library ANSYS and CivilFEM properties will be automatically defined according to active units Section properties. More properties are available through listing In the top right corner of the window, the user may find the Search button (Find). CivilFEM INTRO. Essential 198

199 10.2. Steel Cross Sections Steel sections from the library can be found using the section s search function. The user may specify up to 3 properties. The user can introduce shapes into CivilFEM library by two ways: Reading shape files Using the CivilFEM window CivilFEM INTRO. Essential 199

200 10.2. Steel Cross Sections The user data files for hot rolled shapes are stored in the following folder: %AppData%\CivilFEM\ShapeUserLib Where %AppData% is the System Application Data folder. The files extensions are.bin.mec (mechanical properties) and.geo (geometrical properties). CivilFEM INTRO. Essential 200

201 10.2. Steel Cross Sections Reading files: The user must specify the files (the geometric data file and the mechanical properties file) needed to import the new shapes. If the mechanical data are not available, CivilFEM will calculate them automatically from the defined geometry. CivilFEM INTRO. Essential 201

202 10.2. Steel Cross Sections CivilFEM Window. The user must specify the necessary parameters to define the new shape. The group number must be between 501 and 999 Steel Sections by Dimensions In this window, steel sections by dimensions may be created. To do so, the type of section must be previously selected. The different types of sections supported by CivilFEM are the following: I C T L PIPE BOX After defining the type of section, the desired values are introduced in the corresponding boxes. To identify the notation used in the section s geometry, the user may consult the figure attached in the bottom left corner of the screen. CivilFEM INTRO. Essential 202

203 10.2. Steel Cross Sections Steel Sections by Dimensions This option allows you to define steel sections by their dimensions. Available shapes by dimensions Material number Dimensions Steel Sections by Plates Steel sections may also be defined by plates. To do so, choose the option Steel by Plates and then create each of the plates coinciding with the section. Clicking on the New plate button will create a new plate, and by clicking the Modify plate button you will be able to modify properties of the existing plate. The Delete plate button will delete plates. If one of the plates is clicked with the mouse, the corresponding plate will change the color, and its properties will be displayed in the window. CivilFEM INTRO. Essential 203

204 10.2. Steel Cross Sections Steel Sections by Plates In this window new plates may be defined, or already created ones can be modified or deleted. Properties for the selected plate are also displayed here. Define, modify or delete plates These types of shapes can be checked by codes. To define steel sections by plates, the following must be defined: Plate number Plate material Plate Type: web or flange Connections Plate end points coordinates Steel Sections by Merge Occasionally it is necessary to create a section as a composition of two existing sections. This is performed with the Merge utility, which can be accessed by pressing the Merge button on the section browser window. CivilFEM INTRO. Essential 204

205 10.2. Steel Cross Sections Steel Sections by Merge First, the two sections to be merged must be defined. Definition of first section Definition of second section In the Merge dialog, the following data must be entered: Number: New section Id number. Section 1: First section. Section 2: Second section. Coord. Y: Y coordinate of the axis origin of section 2 (referred to the axis of section 1). Coord. Z: Z coordinate of the axis origin of section 2 (referred to the axis of section 1). : Rotation angle of section 2, measured counter clockwise from the vertical line. Name: Name of the new section. CivilFEM INTRO. Essential 205

206 10.3. Concrete Cross Sections Finally merge the sections. Coordinates of the section 1 respect to the section 2 Section 3 The created section will maintain all the code properties of section 1 and will have all the points, tessella, faces, plates, reinforcement groups, etc. of the two initial sections Concrete Cross Sections 10.3 Concrete Cross Sections It is possible to check and design reinforced concrete beams formed by any generic cross section under axial loading plus biaxial bending, shear, torsion and combined shear and torsion. Cross sections by dimensions Import/Export of a 2D mesh Merge sections CivilFEM INTRO. Essential 206

207 10.3. Concrete Cross Sections In this screen, concrete sections may be created by dimensions. To do so, the type of section must be selected (Shape). Possible section types are: I C T L PIPE BOX After defining the section type, the desired values must be introduced in the corresponding boxes. To identify the notation used in the section s geometry, the user may consult the figure attached in the bottom left corner of the screen. This window allows you to define concrete sections by their dimensions, defining all of their properties automatically. Available shapes by dimensions Material number CivilFEM INTRO. Essential 207

208 10.3. Concrete Cross Sections Concrete sections by dimensions: Rectangular Box T Pipe Circular I Faces Faces Each reinforcement group is located on a face. A single face may have different reinforcement groups associated to simulate several reinforcement layers. The face is a polygonal line defined by at least two points. The reinforcement is located at the left of the face. Reinforcement location Face CivilFEM INTRO. Essential 208

209 10.3. Concrete Cross Sections To define or modify a face: Edit > Faces Create a face Modify a face Click on a face to select it A face does not need to be defined by all the points of the contour of the section; only the beginning and ending points of a straight line are needed. In fact, a face can be inside the section; it does not have to be on the border line of the section. Tessella Face Points CivilFEM INTRO. Essential 209

210 10.3. Concrete Cross Sections Concrete Reinforcement Concrete Reinforcement Once the concrete section has been created and the faces are defined, the user can reinforce it. Types of concrete reinforcement: Bending Shear Torsion To enter the reinforcement definition dialog you must modify the section and enter the Edit > Reinforcement groups: Modify Reinforcement New Reinforcement Group Bending Reinforcement The bending reinforcement of concrete sections is organized in groups, allowing an unlimited number of reinforcement groups. CivilFEM INTRO. Essential 210

211 10.3. Concrete Cross Sections The reinforcement groups can be located on any face defined in the section. The different possibilities that CivilFEM includes regarding the definition of bending reinforcement groups are the following: Total reinforcement group area Reinforcement group area per unit of length Number of bars in a group and its diameter Number of bars in a group per length unit and its diameter Space between bars and diameter of bars When the bending reinforcement is introduced, by means of any of these 5 options, the rest of the data is calculated automatically. It is possible to define a preliminary reinforcement in CivilFEM by activating the Rkey option. Depending on the type of section, the Rkey field will have different values. The reinforcement material is determined in the Rmat field. Bending Reinforcement There are 2 ways to define the bending reinforcement of a cross section: Using the predefined options (RKEY) when creating the cross sections Defining the reinforcement configuration desired by the user Bending reinforcement is defined by groups of bars. To modify the selected predefined bending reinforcement (RKEY), we must change the parameter RKEY to the option User Defined. CivilFEM INTRO. Essential 211

212 10.3. Concrete Cross Sections RKEY options: Box GROUP 2 GROUP 8 GROUP 1 GROUP 3 GROUP 5 GROUP 6 GROUP 7 GROUP 4 RKEY=1 Rectangular GROUP 1 GROUP 1 GROUP 2 GROUP 1 GROUP 2 GROUP 2 GROUP 4 GROUP 3 RKEY=1 RKEY=2 RKEY=3 Circular GROUP 1 RKEY=1 CivilFEM INTRO. Essential 212

213 10.3. Concrete Cross Sections Pipe GROUP 1 GROUP 2 RKEY=1 I Section GROUP 1 GROUP 1 GROUP 2 GROUP 1 RKEY=1 RKEY=2 RKEY=3 T Section GROUP 1 GROUP 1 GROUP 2 RKEY=1 RKEY=2 CivilFEM INTRO. Essential 213

214 10.3. Concrete Cross Sections User defined reinforcement configuration. For defining the bending reinforcement groups we must specify: Class Location Amount Class Scalable: This group may be modified ( scaled ) in the design process. Constant: This group is fixed and will not be scaled. Scalable Constant Initial reinforcement Designed reinforcement Location Face that will support the reinforcement group and the bar situation. Amount By ratio By area Class By bars Face Bar situation By area By ratio By bars CivilFEM INTRO. Essential 214

215 10.3. Concrete Cross Sections Shear Reinforcement The possibilities of input definitions concerning shear reinforcements in CivilFEM are the following: Area per unit length. Input of a stirrups total area and the distance between stirrups. Input of the longitudinal spacing of the stirrups and the diameters of bars. Shear Reinforcement Only one group of shear reinforcement may be defined for each cross section. Shear reinforcement may be defined: By ratio: Area of shear reinforcement per unit of length. Angle with the longitudinal axis Y ALPHA Y X Shear Y Shear Z By area of one stirrup and distance between stirrups. Y ALPHA Y X S Distance between stirrups Shear Y Shear Z CivilFEM INTRO. Essential 215

216 10.3. Concrete Cross Sections By number of legs and distance between stirrups. Y Z Number of bars to Shear Y Number of bars to Shear Z Distance between stirrups Diameter of bars Torsion Reinforcement Torsion Reinforcement Only one group of torsion reinforcement may be defined for each section. Torsion reinforcement has two components: Transversal: Independent of shear reinforcement May be defined: By ratio By area of stirrups and distance between stirrups By diameter of bars and distance between stirrups Longitudinal: Independent of bending reinforcement May be defined: By total area By number of bars and diameter CivilFEM INTRO. Essential 216

217 10.4. Export/Import Cross Sections 10.4 Export/Import Cross Sections Import ANSYS 2D model to CivilFEM 10.4 Cross Sections Export/Import (2D) A section created in ANSYS with elements Mesh200 can be captured by CivilFEM. This capability allows the definition of any cross section shape. CivilFEM ANSYS CivilFEM INTRO. Essential 217

218 10.4. Export/Import Cross Sections The user can define CivilFEM cross sections from any ANSYS 2D model using nodes and MESH200 elements. ANSYS nodes and elements are transformed into points and tessella of the CivilFEM section. The number of the ANSYS coordinate system which will be the section s coordinate system must be specified. By default, this coordinate system will be the active coordinate system. The section coordinate system will be the ANSYS coordinate system defined in this window. It should be taken into account that the nodes and elements must be contained on the YZ plane (X axis normal to the section). Export CivilFEM sections to ANSYS You can export any section defined with CivilFEM to ANSYS. Select the coordinate system to which the section will be exported. This local coordinate system must be created before exporting the section This option allows exporting the points and tessella of a CivilFEM cross section to nodes and elements or keypoints and areas into ANSYS. When you export the section you can create nodes and elements or areas and keypoints only. In the case of creating elements, the superficial and linear tessella are exported as MESH200 elements and the point tessella (reinforcement) are exported as MASS21 elements. CivilFEM INTRO. Essential 218

219 CivilFEM INTRO. Essential Export/Import Cross Sections

220 10.5. User Data Base Cross Sections 10.5 User Data Base Cross Sections 10.5 User Data Base Cross Sections The user can create cross sections by means of any of the CivilFEM possibilities and store them into files defined by the user. Select the section to be stored in the database The user cross section files are stored in the following folder: %AppData%\CivilFEM\CSLib Where %AppData% is the System Application Data folder. The files have the.ucs extension It is possible to use a section defined in a previous session if it has been saved. CivilFEM automatically loads all saved sections. These user defined sections CivilFEM INTRO. Essential 220

221 10.6. List of Cross Section are displayed in a tree form, showing each of the files created and the sections it contains. CivilFEM automatically loads all saved sections The properties are read and listed in the active unit system and code 10.6 List of Cross Section 10.6 List of Cross Section The data of the defined sections can be listed in HTML or ASCII format. Choose between: General List (only general properties are listed) Detailed list (we can select which properties are to be listed) CivilFEM INTRO. Essential 221

222 10.7 Cross Section Edition Cross Section Edition Once the section has been created, if necessary, any characteristic of the section may be redefined. To do so, you must select the desired section. Once it is selected, the group of buttons under New Section will transform to Redefine Section; clicking on any of them will display the window corresponding to the type of section. Therefore, it is possible to transform a section easily Section Edition Sections already defined in CivilFEM, can be redefined if desired. Section redefinition options 10.8 Sections Modification It is possible to modify an existing section. To do so, the user must select the Cross Sections Explorer and press the Modify button. The different possibilities of section modifications are the following: Section Menu The only option available is to exit the modification utility, without saving the changes done (Quit). It is equivalent to the Cancel button in the tool bar menu. CivilFEM INTRO. Essential 222

223 10.8. Sections Modification Select Menu In this menu, subgroups of the selected data can be chosen. The selection may be carried out with the mouse pointer (By Pick), by Material Type or by Material Number. If the selected option is By Pick, CivilFEM will provide a list of entities from which to choose: Points Tesella Faces Reinforcements Plates Edit Menu In this menu the user may access the section s properties edition. CivilFEM INTRO. Essential 223

224 10.8. Sections Modification In this menu the user may access the section properties edition. Common data 10.8 Cross Sections Data Common Data General Properties Data identifying the section: Identification number, type, shape, titles Dimensions Data with the dimensions and geometry of the section: Depth, width, thickness of the flange and web, filet radius Points and Tessella Structure When defining a cross section in CivilFEM the program automatically divides it into points and tessella. Points are used for the geometric description of the cross section and tessella are needed when calculating the section s geometric resistance. CivilFEM INTRO. Essential 224

225 10.8. Sections Modification Points Data Data associated to each section point. Material number associated to the point, material type, Tessella Data Data associated to each tessella such as: Material associated to the tessella, material type, The Refining Tessella option (TRefine) allows the user to increment the number of tessella that form the section (remeshing the section) to obtain more precise results in the calculations carried out. You can increase the number of cross section points and tessella in the cross section window: Edit > TRefine You can change the material of the tessella: Edit > Tessellum Select the tessella to be changed, pick on the change material button and select the number of the Material. CivilFEM INTRO. Essential 225

226 10.8. Sections Modification Type of Tessella: TYPE 1 TYPE 2 TYPE 3 Point Line with two points Line with three points Used for: Representing reinforcements defined by bars Associate LINK and BEAM elements ends (I or J) Used for: Represent plates Associate SHELL elements faces Represent reinforcements uniformly distributed (Fi=0) Used for: Associate SHELL elements faces with edge nodes Represent reinforcements distributed uniformly by curves (Fi=0) TYPE 4 Triangle with three points Used for: Associate SOLID elements faces TYPE 5 Triangle with six points Used for: Associate SOLID element faces with edge nodes TYPE 6 Quad with four points Used for: Associate SOLID element faces TYPE 7 Quad with eight points Used for: Associate SOLID element faces with edge nodes CivilFEM INTRO. Essential 226

227 10.8. Sections Modification Mechanical and Structural Properties Properties used for checking according to codes and for structural analysis (they are transferred to ANSYS as real constants for the calculation of the model). Inertia moment, torsional moment, area, shear center, For composite cross sections CivilFEM automatically homogenizes these properties to the material with a lower number inside the section. Material 2 Material 1 Homogenize to Material 1 CivilFEM allows the section properties to be changed (Edit > Mechanical Properties) just by entering the value in the corresponding edit box. The original value can be retrieved again by clicking on the A button (autocalculate). CivilFEM INTRO. Essential 227

228 10.8. Sections Modification Concrete Sections Data Concrete Sections Data Code properties Additional data for calculating shear and torsion according to codes: Shear width, effective depth, uniform thickness, wall equivalent width Additional data for crack checking according to codes: Bars diameter, effective reinforcement ratio, Steel Sections Data Steel Sections Data Code Properties Possible additional cross section data needed for steel code checks: Areas of holes to obtain the net area, summation of the forces transmitted by the bolts Plates Structure Data concerning the plates decomposition of the section: Number of plates, type, connections, thickness, coordinates, class, reduction factors The plates structure is automatically defined when creating any type of steel section. The class and reduction factors of the section are the output data of calculations with codes (Eurocode 3, LRFD and British Standard). CivilFEM INTRO. Essential 228

229 10.9. Concrete Code Properties 10.9 Concrete Code Properties 10.9 Concrete Code Properties Concrete code properties are additional cross section properties needed to check and design shear and torsion reinforcement and to carry out crack checking according to codes or standards. Each concrete code has its own code properties. These properties are automatically defined, for sections by dimensions, when defining the cross section geometry. It is only necessary to redefine these properties if you want to use properties other than the default values or if you are using a generic shape cross section. To edit Code properties, select a concrete section and press modify. Then Edit > Code Properties (Main Menu > Civil Preprocessor > Cross section > Modify) CivilFEM INTRO. Essential 229

230

231 10.9. Concrete Code Properties 11 Shell Vertex CivilFEM INTRO. Essential 231

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233 11.1 Shell Vertex Concept Shell Vertex Concept 11.1 Shell Vertex Concept A shell element concept equivalent to the beam cross section used to represent properties of a particular vertex of the shell element. Shell vertices contain data and properties of the shell element nodes. Steel shell Enter the thickness Select the material It is also possible to Create a new vertex, Modify an existing vertex, Delete it, Create a vertex from another vertex already defined, and List created vertices. When a vertex is created or modified, a window with two sections is displayed. The first one refers to general parameters and the second one to Reinforcement. CivilFEM INTRO. Essential 233

234 11.2. Shell Reinforcement Enter the thickness Concrete shell Select the material 11.2 Shell Reinforcement May be bending or/and shear reinforcement (concrete shells). Parameters for bending reinforcement: Material: reinforcing steel. Reinforcement cover. Reinforcement per unit of length: Top surface in X direction Bottom surface in X direction Top surface in Y direction Bottom surface in Y direction KRnf: Braced reinforcement bars (only for CEB method) ALP: Reinforcement angle (only for WOOD S method) THETA: Angle of compressive strut CivilFEM INTRO. Essential 234

235 11.2. Shell Reinforcement 11.2 Shell Reinforcement (concrete shell) It is not necessary to define an initial amount of reinforcement; only define the reinforcement material number (Rmat). Reinforcement cover Material Reinforcement per unit length Braced reinforcement bars Angle of reinforcement (only for Wood method) Concrete compression strut angle CivilFEM INTRO. Essential 235

236 11.2. Shell Reinforcement Parameters for shear reinforcement: Material: reinforcing steel. The reinforcement can be defined by ratio or by number of bars. Reinforcement by ratio: Ass Reinforcement by number of bars: NX, NY, SX, SY, Fi 11.3 Shear Reinforcement (concrete shell) Material By Ratio or By Number of bars SX: Longitudinal spacing of the bars Ass: Reinforcement area per unit area NX or NY: Number of bars per unit length Fi: Diameter of bars (by number of bars) CivilFEM INTRO. Essential 236

237 11.3. List of Shell Vertex 11.3 List of Shell Vertex 11.4 List of Shell Vertex The data of the defined shell vertex can be listed in HTML or ASCII format. Choose between: Short List Detailed list CivilFEM INTRO. Essential 237

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239 12 CivilFEM Member Properties CivilFEM INTRO. Essential 239

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241 12.1. Member Properties Concept 12.1 Member Properties Concept The Member Properties setting contain additional data for check and design according to codes. These data embrace properties not directly associated to the transversal cross section but to its functioning as a member of a group of elements in a model Member Properties Concept Member properties are data of the structure needed to check according to codes and are not directly defined as cross sections, element properties, or geometry. Member properties depend on the active code. CivilFEM associates member properties to Beam & Shell Properties or Solid Sections. The properties already created are listed in the member properties window. Moreover, New Properties can be created and existing properties Deleted, Modified, Copied or Listed. CivilFEM INTRO. Essential 241

242 12.1. Member Properties Concept The following window is displayed when a member property is created or modified. It is possible to change the property Number and Name in this window. The different code-dependent parameters may be modified in the first tabs. In the last tab, non-linearities for CivilFEM, non-linear beam calculations are activated or deactivated (Bridges and Civil Non Linearities Module). CivilFEM INTRO. Essential 242

243 12.2. Steel Member Properties 12.2 Steel Member Properties 12.2 Steel Member Properties Typical member properties are: Member description: Column, beam, Buckling lengths: Unrestrained length, length between stiffeners, Coefficients: K, Kw, Beta, Chi, Default values Active code Each type of checking process requires specific member properties. The program assigns the appropriate values from the code. All of these values may be changed by the user. To determine what each variable means, look up the code or press the help button in this window. Not all code checking types require the definition of all the member properties. ANSYS does not need these properties to solve the model. CivilFEM INTRO. Essential 243

244 12.3. Concrete Member Properties 12.3 Concrete Member Properties 12.3 Concrete Member Properties Typical member properties are: Strength reduction factor (used in certain codes such as AS3600) Default values Active code The strength reduction factor is a member property that can be globally assigned to the whole structure (CivilFEM Setup), or assigned to each of the elements using Member Properties. CivilFEM INTRO. Essential 244

245 13 CivilFEM Beam & Shell Properties CivilFEM INTRO. Essential 245

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247 13.1. Beam & Shell Properties and Real Constants 13.1 Beam & Shell Properties and Real Constants Beam and Shell Properties contain all the properties of a beam or shell element type, not determined by their type, material, or location of nodes. Once the cross sections (for beam elements) or the shell vertex (for shell elements) are defined, the definition of the Beam and Shell Properties will associate the end of the element with the corresponding Member Property and any other properties (offsets, etc.) Beam & Shell properties and Real Constants Beam & Shell properties in CivilFEM are linked to ANSYS sections and sets of real constants. The number identifying the CivilFEM beam & shell property corresponds to the real constants set number (or section number for BEAM188 BEAM189, SHELL181 and SHELL281) in ANSYS. When assigning a Beam & Shell property to an element, the corresponding ANSYS real constant set or section is assigned. When deleting a Beam & Shell property with CivilFEM commands, the corresponding real constant set or section in ANSYS is automatically deleted. It is important to assign the Real Constant or Section attribute to the geometry before meshing. This attribute is the Beam & Shell Property number. It is important to indicate during the definition of the property the element type to which the Beam and Shell Property will be associated for the correct definition of the real constants. CivilFEM INTRO. Essential 247

248 13.2. Beam & Shell Properties Definition Beam & Shell Properties contains all the properties of a beam or shell element type, not determined by its type, geometry, material or location of nodes. It includes the data of sections of a beam element and of all vertices of a shell element. For a beam element, a Beam & Shell property will contain the following: Beam & Shell property = Cross section (I) + Cross section (J) + Member property + Offsets For a shell element, a Beam & Shell property will contain the following: Beam & Shell property = Shell vertex (I) + Shell vertex (J) + Shell vertex (K) + Shell vertex (L) + Member property + Offsets + EFS 13.2 Beam & Shell Properties Definition 13.2 Beam & Shell Properties Definition Procedure: 1 st step: cross sections definition (beams) or shell vertex (shells). 2 nd step: definition of member properties in case its necessary. 3 rd step: definition of beam & shell property CivilFEM INTRO. Essential 248

249 Beam Property Beam & Shell Properties Definition The Beam Property window is divided into: Upper Menu The beam s general properties are defined here: Number, Name, Beam type (Ename) and Offset location (Offset). Cross Section (left side) where the type of beam section is chosen and its offsets can be seen and modified. Member Properties (right side) where member properties of the beam are chosen and can be reviewed. On the left side (Cross Section), it is possible to choose if the beam has a constant section or is a tapered beam (pressing on the Constant Section button will change the screen to display Variable Section) It is possible to define variable cross sections for both element ends by choosing an appropriate element type (BEAM44 or BEAM54). Element type Offset definition Cross section Member properties Node location (offset) List of ANSYS Real Constants There is a button in the bottom side to display the Real Constants assigned to the beam. Shell Property The window is the same in the case of Shell Properties, but beam ends (sections) are substituted by shell ends (vertex). Instead of displaying each end, two fields with the vertex Thickness and the Material are shown. For SHELL63 elements, the Elastic Foundation Stiffness (EFS) edit box is available. CivilFEM INTRO. Essential 249

250 13.2. Beam & Shell Properties Definition It is possible to define variable Shell sections by choosing an appropriate element type. Element type Shell vertex Member properties Elastic Foundation Stiffness (Shell 63) List of ANSYS real constants Offset (Shell 181 and 281) Elastic foundation stiffness is only available for SHELL63 elements. Node location (offsets) Offset Definition When creating a BEAM44 or BEAM54 The nodes location can be modified by entering an offset. Offset definition (~BMSHOFF command). CivilFEM INTRO. Essential 250

251 13.2. Beam & Shell Properties Definition The node is located at the center of gravity of the section. The node is located at the section s axis origin. The node is defined by entering its coordinates. The node is located at the shear center of the section. User: These coordinates are referred to the section axis. The node is defined by entering its coordinates or by clicking any of the 9 typified points on the section. Coordinates of nodes When creating a SHELL181 or SHELL2891 The nodes location can be modified by entering an offset. Offset definition (~BMSHOFF command). CivilFEM INTRO. Essential 251

252 13.3. Beam 188 and 189 elements The node is located at the any height. The node is located at the Top of the shell. The node is located at the Bottom of the shell. User: These coordinates refer to center of the shell element. The node is defined by entering the vertical coordinate. Coordinate of node 13.3 Beam 188 and 189 elements 13.3 Beam 188 and 189 elements Beam 188 and 189 elements allow to render the real shape of the section on the beam model: PlotCtrls > Style > Size and Shape 1 Display of element real shape Y X Z MN MX ANSYS 10.0 NOV :31:27 NODAL SOLUTION STEP=1 SUB =1 TIME=1 SX (AVG) RSYS=0 PowerGraphics EFACET=1 AVRES=Mat DMX = SMN =-.146E+08 SMX =.146E E E E E E E E E E E+08 This allows the user to plot results (such as stresses) on the 3D shape of the element, not only on the directrix of the beam. CivilFEM INTRO. Essential 252

253 14 CivilFEM Solid Models Analysis CivilFEM INTRO. Essential 253

254

255 14.1 Solid Section Concept Solid Section Concept 14.1 Solid Section Concept Sections associated to elements of 2D and 3D models of finite elements. It is used to extend the checking capabilities of the program to generic models in 2D/3D with elements LINK, BEAM, SHELL, PLANE and SOLID. CivilFEM allows the definition of solid sections from a 2D model containing the following two-dimensional elements: LINK1, PLANE2, BEAM3, PLANE42, BEAM54, PLANE82, PLANE182, PLANE183. CivilFEM allows the definition of solid sections from a 3D model containing the following three-dimensional elements: BEAM4, LINK8, LINK10, PIPE16, PIPE20, BEAM23, BEAM24, SHELL41, SHELL43, BEAM44, SOLID45, SHELL63, SOLID64, SOLID65, SOLID72, SOLID73, SOLID92, SHELL93, SOLID95, SHELL143, LINK180, SHELL181, SOLID185, SOLID186, SOLID187, BEAM188, BEAM Capturing Solid Sections To define a solid section from a 2D or 3D model, it is necessary to select the plane of nodes that defines the section situation and the elements that provide their characteristics to the section. The definition of a solid section implies the automatic definition of the associated cross section. This cross section will be created by points, associated with the selected nodes of the model, and by tessella, corresponding with the selected elements of the model that share CivilFEM INTRO. Essential 255

256 14.2. Capturing Solid Sections those nodes. The tessella will have the same properties assigned to their corresponding elements (material, type ). This way, the points and tessella will be linked to the nodes and elements of the model. This union will be used for the calculation of stresses and the integration of forces and moments. For the definition of the solid section, in addition to selecting the plane of nodes, it is necessary to define a local Cartesian coordinate system whose axes Y-Z define the plane of nodes. This coordinate system will be the coordinate system of the associated cross section once it is captured Capturing Solid Sections It is necessary to select the plane of nodes that defines the section situation and the elements that provide their characteristics to the section. A local Cartesian coordinate system (Y-Z axes) defines the plane of nodes. The tessellas will have the same properties assigned to their corresponding elements (material, type ). Automatic generation of cross section Plane of nodes CivilFEM INTRO. Essential 256

257 15 Load Combinations CivilFEM INTRO. Essential 257

258

259 15.1. Typical Problems 15.1 Typical Problems CivilFEM provides, through the combinations module, the possibility of operating with a results set and combining them in such a way that given targets can be achieved. Therefore, the results combination is based on the search of the combination among a certain data set that, following certain rules, fulfills the given targets at each node of the structure. Listed below are some of the questions that CivilFEM s load combination module can solve Typical Problems Problem example 1: Loads in building What is the maximum moment in section A-A? Where should the variable load be located? Should the wind blow from right to left or from left to right? Is the dead load favorable or unfavorable??? A A???? CivilFEM INTRO. Essential 259

260 15.1. Typical Problems Problem example 2: Mobile loads Where should the two engines be located for the stress to be maximum at point P???? P Problem example 3: Selecting coefficients Scheme of combinations in Eurocodes E γ G γ G γ Q G, Gravity k, Gravity G, Dead k, Dead Q, Live k, Live γ ψ Q γ ψ Q... Q, Wind 0, Wind k, Wind Q,Thermal 0, Thermal k, Thermal g G = 1.00 or 1.35? g Q = 1.00 or 0.00? You must decide independently for each section of the structure. CivilFEM INTRO. Essential 260

261 15.2. Main Applications of CivilFEM Combinations 15.2 Main Applications of CivilFEM Combinations 15.2 Main Applications of CivilFEM Combinations Mobile loads Combinations with variable coefficients (favorable/ unfavorable) Actions in different directions (wind, earthquakes, ) Combinations according to codes logic Example: 2x300kN located in the most unfavorable position Border Virtual lane 1 Border Virtual lane 2 Border 2x200kN located in the most unfavorable position Permanent actions (G k ) Self weight Dead load of 20 kn/m Road traffic actions (Q k ) Vehicles (Double-axis) 2x300 kn in virtual lane 1 2x200 kn in virtual lane 2 Uniformly distributed loads 9.0 kn/m 2 in virtual lane kn/m 2 in virtual lane kn/m 2 in the other areas Target: Maximum MZ Minimum MZ CivilFEM INTRO. Essential 261

262 15.2. Main Applications of CivilFEM Combinations Eurocode 1: Permanent and transient situations (simplified) The program will select the coefficients to apply for each target and element. Permanent actions G G k Q Variable actions Q k Safety factor for permanent actions: G = 1.00 if it is favorable G = 1.35 if it is unfavorable Safety factor for variable actions: Q = 0 if it is favorable Q = 1.00 if it is unfavorable file.rst Start State Load state 1 Self weight Load state 2 Dead load Load states 3 to 21 Vehicle 1 Load states 22 to 40 Vehicle 2 Load states 41 to 58 Uniformly distributed load Combined results file.cmb or file.cvmb Combination 1 Permanent actions Combination 2 Vehicle in virtual lane 1 Combination 3 Vehicle in virtual lane 2 Combination 4 Uniformly distributed loads Combination 5 Road traffic actions 1 st level combinations 2 nd level combinations 3 rd level combinations Combination 6 Permanent and transient situations CivilFEM INTRO. Essential 262

263 15.3. General Procedure I. Obtain All possible Load Cases 15.3 General Procedure I. Obtain All possible Load Cases With CivilFEM Combination module you can define certain combination rules and obtain all the possible load cases that can be generated following those rules General Procedure I Define combination rules Start States of each combination Combination type Coefficients for each start state Calculate Obtain all the possible load cases Results are appended in the results file (from the last load step defined). This procedure will create new load steps that will be appended after the last step is defined in the RST and RCV files. Postprocessing of new load steps is done in the same way as for solved load steps. CivilFEM INTRO. Essential 263

264 15.4. General Procedure II. Combine Results of the Whole Structure by Searching for Specific Targets 15.4 General Procedure II. Combine Results of the Whole Structure by Searching for Specific Targets It is also possible to combine the initial load states following certain combination rules by looking for a specific target (or a group of targets) instead of combining all of the results. This will provide an envelope of results for the whole structure. For example, combining for the maximum shear force will create an envelope of maximum shear forces that can be produced for all the possible combinations throughout the structure. Apart from obtaining the enveloped results, CivilFEM will also provide the concomitant results inside the same group. This is to say, these results occur at the same time as the target is obtained. For example, for a beam element structure for which the maximum shear force is the desired target, CivilFEM will also provide the axial force or the bending moments that happen at the same time (for the same combination) as the maximum shear force (the load combination will be different for each point of the structure) General Procedure II Define combination rules Start States of each combination Combination type Coefficients for each start state Define Targets Calculate Obtain envelopes searching for the targets Point to combined results (new CMB and CVMB files) Read combined results This procedure is very useful when the load combinations may generate many load cases (moving vehicle, for example). CivilFEM INTRO. Essential 264

265 15.5. General Procedure III. Search for a Specific Result at a Specific Location 15.5 General Procedure III. Search for a Specific Result at a Specific Location Sometimes it may be useful to obtain a specific result at a specific location or entity (beam, node, cross section, solid section, etc.). An example would be obtaining the maximum vertical displacement at the center of a span. In this case, the definition of the combination rules is needed; however, instead of combining all the results, an inquiry will be done for a certain target at a specified location General Procedure III Define combination rules Start States of each combination Combination type Coefficients for each start state Define Targets Inquire Worst hypotheses and coefficients Results for certain points Global Concomitance Concomitant loads Results at one entity (node, element, section, etc.). Not for the whole model. CivilFEM INTRO. Essential 265

266 15.6. Define Combination Rules 15.6 Define Combination Rules Start States 15.6 Defining Combination Rules Start States Each combination has its own start states The start states can be obtained from: Jobname.RST or Jobname.RCV Combinations of CivilFEM (nested combinations) From jobname.rst or jobname.rcv a start state can be identified by: The Load Step and Substep The number of Data Set From CivilFEM combinations, a start state can be identified by: The combination number Combination Rules Combination Rules Combination Rules are logic relations between Start States. Each combination rule has its own Start States. A combination rule may have any number of Start States (up to a maximum of 1,000,000). The result of the combination is called the combined result. Combination rules can be nested unlimited times. That means that the combined result of the combination i can be a start state for the combinations i+1, i+2,, n, and combined results of combination i+1 may be a start state for combinations i+2, i+3,, n E γ Gravity Gk, Gravity γg, Dead Gk, Dead γq, Live Qk, Live γq,wind ψ0,wind Qk, Wind G,... Combined result Start State Combination Rule CivilFEM INTRO. Essential 266

267 15.6. Define Combination Rules There are 8 Types of Combination Rules Addition [ADD] Addition with Variable Coefficients [ADDVC] Incompatible or Exclusive Start States [INCOMPAT] Compatible Start States [COMPATIB] Start States Option [OPTION] Opposed Start States [OPPOSED] Selection [SELEC] Selection with variable coefficients [SELECVC] Addition [ADD] Description Addition of all the Start States multiplied by fixed coefficients Required Coefficients 1 Coefficient per Start State Additional Data None Notes It is the classic addition It is equivalent to ANSYS combinations CivilFEM INTRO. Essential 267

268 15.6. Define Combination Rules Addition with Variable Coefficients [ADDVC] Description Addition of all the Start States multiplied by variable coefficients Required Coefficients 2 Coefficients per Start State Additional Data None Notes It can be used in code combinations For example C = fg.g + fq.q Incompatible or Exclusive Start States [INCOMPAT] Description As maximum one Start State may be selected (one or none) from the defined ones Required Coefficients None Additional Data None Notes Used for representing mobile loads which can only occupy one position of the possible ones CivilFEM INTRO. Essential 268

269 15.6. Define Combination Rules Compatible Start States [COMPATIB] Description Addition of any subset of the Start States defined (none, one, several or all of them) Required Coefficients None Additional Data None Notes For representing mobile loads which may occur simultaneously (surface loads) Option [OPTION] Description Only one Start State is selected from the ones defined Required Coefficients None Additional Data None Notes For selecting from several hypotheses. For example, different code hypotheses... CivilFEM INTRO. Essential 269

270 15.6. Define Combination Rules Opposed Start States [OPPOSED] Description Addition of all the Start States, but with each one multiplied by or Required Coefficients None Additional Data None Notes For actions which may act indistinctly in two opposed directions (earthquake, wind...) Selection [SELECT] Description Addition of a fixed number of Start States selected from the ones defined Required Coefficients None Additional Data Number of Start States to add Notes For mobile loads which can act simultaneously in more than one position CivilFEM INTRO. Essential 270

271 15.6. Define Combination Rules Selection with variable coefficients [SELECVC] Description Addition of a fixed number of Start States; each can be multiplied by two coefficients Required Coefficients 2 Coefficients per Start State Additional Data Number of Start States to add Notes It is the most general type; by degeneration, it is adapted to any of the previous types Selection with variable coefficients [SELECVC] In a SELECVC combination the program adds a subgroup selected from the start states defined for the combination rule and it multiplies each by a different coefficient. The program selects which ones are to be added for each target and for each point of the structure Start States selected Combination Rule Start State 1 Start State 2 Start State 4 Start State 3 Start State 5 CivilFEM INTRO. Essential 271

272 15.6. Define Combination Rules Summary of Combination Rules TYPE Coefficient Number of Start Maximum Minimum States to add ADD C1 C2 = C1 ALL ADDVC C1 C2 ALL INCOMPAT COMPATIB 0 1 ALL OPTION OPOSED 1-1 ALL SELECT 1 1 NADD SELECTVC C1 C2 NADD These data should be introduced by the user. CivilFEM INTRO. Essential 272

273 15.7 Combination window Combination window Once the combinations module has been initialized, any combination can be defined with of all its start states through this window: Tool bar Information about the selected combination or new combination Information and coefficients of the selected start state Combinations and families tree Default coefficients that will be assigned to the new start state Visualization modes of the start state list Start states list. It includes the defined combinations, the available load steps and sub steps and all the defined datasets. CivilFEM INTRO. Essential 273

274 15.7. Combination window 15.7 CivilFEM Combination window Combinations Tree The combinations tree has a list of all the defined combinations, and each combination contains a list of the start states that it combines. Each start state can be a data set (load step with substep) or another combination previously defined. It has two main groups: Combinations. It groups the list of all the combinations for the defined loads. Families. It groups the list of all the defined families (see the Bridge and Civil Non Linearities Module in CivilFEM help). After clicking with the right mouse button on the different elements of the tree, a contextual menu will appear showing the actions that can be performed on this element or group of elements. CivilFEM INTRO. Essential 274

275 15.7. Combination window Tool Bar Tool Bar The tool bar is located at the upper part of the window. The tool bar has two parts: the fixed part, that remains unchanged at any time, and the variable part, that adapts to each situation, showing only the buttons that can be used at each moment. Information Window This window, located at the right of the objects tree, has the following functions: To show the properties of each selected object. Whenever an object is selected (combination, load step, dataset, family, etc.), the window will show all its properties. To allow modification to the data. CivilFEM INTRO. Essential 275

276 15.7. Combination window To serve as a dialog box with certain actions. In some cases, for example creating a new combination, it is necessary to enter a series of values or properties to perform the desired action. To create a new combination, it is necessary to define the type of combination and the number of start states: Defining Combination Rules Define the type of combination and the number of Start States Before starting with calculations, you must define all the combination rules and targets. Combination name Combination number Number of Start States included in this combination rule Type of combination Start States List This is a list of possible start states to choose from for a combination. The combinations previously defined can also be start states for a new combination (nested combinations). CivilFEM INTRO. Essential 276

277 15.7. Combination window Defining Start States Define the start states of each combination rule Origin of the Start State: Load Step and Sub Step [file RST] or [file RCV] Data Set [file RST] or [file RCV] Previous combination [file CMB] or [file CVMB] Coefficients window When a combination is defined, the default coefficients have to be introduced if they are required. These coefficients are applied to all the start states which form the combination. Once the combination has been created, the start states coefficients can be changed by selecting the desired start state and changing their value at Start State window. CivilFEM INTRO. Essential 277

278 15.7. Combination window Defining Coefficients Define the coefficients of each start state (if required) Maximum coefficient Minimum coefficient If a default value is introduced, it will be applied to the rest of Start States. Combination Definition Process Combinations Definition Process In order to define a new combination, the following steps should be followed: 1. Select the group of all the combinations. 2. Enter the information of the new combination: CivilFEM INTRO. Essential 278

279 15.7. Combination window 3. Press the button to create the new combination. 4. Select from the start state list, the start states desired to be included in the combination (more than one can be selected while pressing the control key [CTRL]). The default coefficients for the start states in the combination must also be defined. 5. Select the combination from the tree (it still does not have its start states defined): 6. Drag the selected start states from list with the mouse and drop them into the combination: CivilFEM INTRO. Essential 279

280 15.8. Obtain All Possible Load Cases 6. Another possibility (instead of drag & drop ) is to press the contextual button in the tool bar. This way, the combination can also be completely defined: 15.8 Obtain All Possible Load Cases 15.8 Obtain All Possible Load Cases Following the General Procedure I, you can obtain ALL the load cases that the combinations define. Caution: This may generate many load cases. CivilFEM INTRO. Essential 280

281 15.9. Defining Targets Following Procedure I, CivilFEM will generate all the load cases defined by the combination rules. These new load cases will be appended to the RST and RCV files, following the previously solved load steps Defining Targets 15.9 Defining Targets Targets are results that have to be maximized or minimized. Strains, stresses, forces, moments, displacements or reactions are TARGETS. TARGETS may be maximum, minimum or maximum in absolute value. You can define as many targets as you wish; each one will generate its own results for each combination. The calculation of all of the combinations can be a long process, so it is important to define all the targets before doing the combinations. To define targets use: Main Menu > Civil Postprocessor > Combine Results > Def One Target CivilFEM INTRO. Essential 281

282 15.9. Defining Targets Targets are divided into ANSYS and CivilFEM targets: Targets related to elements (ANSYS) Beam elements Shell elements Solid elements Axisymmetric elements Targets related to nodes (ANSYS) Movements Reactions Targets related to element ends (CivilFEM) Cross sections Shell vertex ANSYS Targets CivilFEM Targets Cross Section (CROSS) CivilFEM targets include forces, moments and stresses and strains at the section s points calculated by CivilFEM for beam elements and stored in the CivilFEM results file (jobname.rcv). For cross sections, the number of points varies and may grow indefinitely, so the targets for these points are limited to 14. Therefore, the number of available targets is 6 relative to forces and moments, 14 to stresses, and 14 to strains. In the last two cases, the target refers to a point and a component of the stress or strain in that point, both defined by the user. Concomitance is established for all the data which compose the forces and moments in the section and for all of the components of the stresses and strains of all the points in the section. Shell Vertex (VERTX) CivilFEM targets include forces, moments, and stresses and strains calculated by CivilFEM for shell elements vertices and stored in the CivilFEM results file. A target is defined by its referred datum (for example FX) and by its TYPE (Minimum, Maximum or Maximum in absolute value). CivilFEM INTRO. Essential 282

283 15.9. Defining Targets Defining One Target All the combinations defined use all the Targets defined Target Number Target s Group Type of Target If you select CROSS as a target group, you can define the cross section points as either a stress or strain target. User Point number Cross section point number Stress or strain CivilFEM INTRO. Essential 283

284 Combine Searching for Targets Combine Searching for Targets Following Procedure II, it is possible to obtain an envelope of certain results and the concomitant results associated to these envelopes Combine Searching for Targets All the combination rules simultaneously search for the targets List of all the targets, combination rules, start states and coefficients CivilFEM will create two additional results files:.cmb and.cvmb in which the enveloped results will be stored Point to Combined Results After combining targets, it is necessary to point to the correct results file for postprocessing:.rst/.rcv for the initial load steps..cmb/.cvmb for the enveloped or combined results. CivilFEM INTRO. Essential 284

285 Point to Combined Results Point to Combined Results You can read the Original and the Combined results Command ~CMBDAT allows the user to select or to point to original or combined results. Afterwards, the user may use ~CMB or ~CFSET commands to recall to memory the combination and target that will be postprocessed. Original Results Combined Results *.RST *.CMB ~COMBINE *.RCV *.RCV *.CVMB 1 2 ~CMBDAT CivilFEM INTRO. Essential 285

286 Point to Combined Results The combined results are written in file. CMB or file. CVMB depending on the origin of the results being combined. File.CMB will contain combinations from file.rst. Therefore, since these combinations come from ANSYS results file, code checking or reinforced design are not allowed. File.CVMB will contain combinations from file.rcv. Therefore, since these combinations come from CivilFEM results file, code checking or reinforced design are allowed. If the user requires CivilFEM code checking and design capabilities for a particular combination, a CivilFEM Target (CROSS or VERTX) should be defined. Each combination result occupies a Load Step in file.cmb or file.cvmb. Therefore, you will have as many Load Steps as combination rules defined. The results corresponding to each target are written as a Sub Step of each Load Step. Therefore, combinations correspond to Load Steps and Targets correspond to Sub Steps. You will have as many Sub Steps as targets defined All the Load Steps of file.cmb have the same amount of Sub Steps The results in the combined results files (.CMB/.CVMB) can be postprocessed in the same way as solved results (plot and list results, code checking, etc.) CivilFEM INTRO. Essential 286

287 Reading Combined Results Reading Combined Results Once the combined results file is selected, the combination rule, containing the data to be loaded, can be specified through the target number or by description. In case the target number is not indicated, the target with the lower number will be loaded Reading Combined Results Reading Results (by number or by description) Enter the number of the combination to read. The last combination by default Target groups and targets defined previously Example of combined results in a hexagonal shell Combination: 1, target: 1 (absolute Z maximum displacement) Combination Target CivilFEM INTRO. Essential 287

288 Inquiring Inquiring Inquiring CivilFEM allows the user to determine which coefficients to multiply the start states of a combination and where the loads must be applied to achieve a particular target at a determined node or element of the structure. This can be done with command ~CMBINQ or by menu: Main Menu > Civil Postprocessor > Combine Results > Nodal Results or Element Results. Target, node, and combination rule required Listing values Loading concomitance in the whole model CivilFEM INTRO. Essential 288

289 Concomitance Target, node, and value required Combination Rule Worst Combination UZ* for the selected node and rule Inquiring can be done before combining. Combinations are not required to obtain inquired results Concomitance Concomitance CivilFEM allows the user to identify any concomitant value of each point and the group to which the TARGET belongs to. The concomitant loads in the model for the combination rule selected will be available until a new data set is specified by means of the ~CFSET or ~CMBDAT commands. CivilFEM INTRO. Essential 289

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291 16 Concrete Check and Design CivilFEM INTRO. Essential 291

292

293 16.1. General Concepts 16.1 General Concepts Checking and reinforcement design of reinforced concrete beams in CivilFEM includes structures made of 2D and 3D beam elements under axial loading plus biaxial bending, shear, torsion, and combined shear and torsion (depending on the Code or Standard). The check and design process of reinforced concrete beams under axial loading plus biaxial bending is based on the 3D interaction diagram of the cross section to be analyzed. The 3D interaction diagram contains the (FX, MY, MZ) forces and moments corresponding to the section s ultimate strength states. Using the diagram, the program is able to check and design the section taking into account the previously obtained forces and moments acting on the section. This process allows the consideration of any generic section and the check and design of sections consisting of different concretes and reinforcement steels General Concepts Reinforcements can be checked or designed according to the Ultimate Limit State with the CivilFEM utilities for concrete checking. Codes Eurocode 2 ACI 318 ACI 349 (CivilFEM NPP) ACI 359 (CivilFEM NPP) CEB-FIP Spanish code EHE British Standard 8110 Australian code AS3600 Chinese code GB50010 Brazilian code NBR6118 AASHTO Standard Specifications for Highway Bridges Indian code IS456 Russian code SP Structural Design Code for Buildings (CivilFEM NPP) CivilFEM INTRO. Essential 293

294 16.1. General Concepts Code check CivilFEM checks the structure with a fixed amount of reinforcement and shows the safety factor of each element. Code design CivilFEM checks the structure and multiplies the initial scalable reinforcement until obtaining a safety factor (1/criterion) as close as possible to Code check has the following options available for beam elements and solid sections: 2D Axial force + Bending Moment. CivilFEM uses the interaction diagram of each section, taking into account the design stress-strain curve for each of the materials of the section. The moment of the Y or Z section is considered. 3D Axial force + Bending Moment. CivilFEM uses the interaction diagram of each section, taking into account the design stress-strain curve for each of the materials of the section. Moments in two directions are applied to the section. Shear, Torsion, and combined Shear & Torsion. Availability of these three checks depends on the code formulation. Cracking. If available, CivilFEM can obtain the cracking criterion according to code. A decompression analysis can also be made to analyze the state of the concrete structure. For shell elements, the following options are available: Check under bending moments and in plane loading, using the CEB-FIP formulation. Check for bending moments, axial loads, in plane shear loads, out of plane shear loads, and torsional moments using the Orthogonal Directions Method. CivilFEM INTRO. Essential 294

295 16.1. General Concepts Check for bending moments, axial loads, in plane shear loads, out of plane shear loads and torsional moments using the Most Unfavorable Directions method. Check the shear reinforcement (not available for all codes). CivilFEM can obtain the needed reinforcement (design) in order to fulfill the code requirements. For beam elements, the following design options are available: 2D Axial force + Bending Moment. CivilFEM uses the interaction diagram of each section, taking into account the design stress-strain curve for each of the materials of the section. The moment of the Y or Z section is considered. Scalable reinforcement will be increased/decreased until the section reaches a safety factor of 1.0, according to the code. 3D Axial force + Bending Moment. CivilFEM uses the interaction diagram of each section, taking into account the design stress-strain curve for each of the materials of the section. Moments in two directions are applied to the section. Scalable reinforcement will be increased/decreased until the section reaches a safety factor of 1.0 according to the code. Shear, Torsion and combined Shear & Torsion. Availability of these three checks depends on the code formulation. Shear and torsional reinforcement will be increased/decreased until the section reaches a safety factor of 1.0 according to the code. For shell elements, the following options are available: Design under bending moments, using the Wood-Armer formulation. Design under bending moments and in plane loading, using the CEB-FIP formulation. Design for bending moments, axial loads, in plane shear loads, out of plane shear loads and torsional moments using the Orthogonal Directions Method. Design for bending moments, axial loads, in plane shear loads, out of plane shear loads and torsional moments using the Most Unfavorable Directions method. Design the shear reinforcement (not available for all codes). CivilFEM INTRO. Essential 295

296 D Axial + Bending Check Results The available results of a concrete check or design are grouped into two blocks: Beam Results This group includes the results for beam cross sections as well as the results of check or design of a solid section. The available results to be plotted or listed depend on the type of checking or design that has been carried out. Shell Results This group includes the results for shell element vertices D Axial + Bending Check D AXIAL+BENDING CHECK CivilFEM checks the structure with the initial reinforcement amount. Stresses can be limited for concrete or for the reinforcement This check only complies with the section s strength requirements, thus ignoring the requirements related to the minimum reinforcement amounts or dispositions for each code and structural typology. CivilFEM INTRO. Essential 296

297 D Axial + Bending Check The check criteria provide information about the relationship between the acting force and moment combination and the ultimate force and moment combination. If this criterion is less than 1.0, in such a way that the forces and moments acting on the section are inferior to its ultimate strength, the section is safe (element is OK). On the contrary, for criterion higher than 1.0, the section will be considered as not valid (element is NOT OK). The following results are available for each element: Elements that are OK and NOT OK according to code specifications Criterion Interaction diagram Code check/design results Red elements need more reinforcement Elements with Criterion < 1 are O.K. CivilFEM INTRO. Essential 297

298 D Axial + Bending Check Interaction Diagram 2D Interaction diagram Design loads Ultimate strength Without reinforcement Inside OK Outside Not OK This is a 2D interaction diagram. It includes all the necessary information for checking as well as design. Effects of actions, ultimate strength, safety information, as well as strength with and without reinforcement can be seen. The criterion provided is the ratio between the distances of the center of the diagram to the design loads point and the center of the diagram to the ultimate strength. CivilFEM INTRO. Essential 298

299 D Axial + Biaxial Bending Check D Axial + Biaxial Bending Check D AXIAL+BIAXIAL BENDING CHECK CivilFEM checks the structure with the initial reinforcement amount and shows the following results for each element: Elements that are OK and NOT OK according to code specifications Criterion 2D/3D Interaction diagram Stresses can be limited for concrete or for the reinforcement As for the 2D axial + bending check, the check criteria provide information about the relationship between the acting axial force and moment combination and the ultimate axial force and moment combination. If this criterion is less than 1.0, the forces and moments acting on the section are lower than its ultimate strength: the section is safe (element is OK). For criterion higher than 1.0, the section will be considered as not valid (element is NOT OK). CivilFEM INTRO. Essential 299

300 D Axial + Biaxial Bending Check 3D Interaction Diagram 3D Interaction diagram Above is a 3D interaction diagram. Interaction diagram is a surface in the space (FX, MY, MZ) which defines the boundary of the failure criteria of the cross section. Therefore, this surface contains the forces and moments corresponding to the section s ultimate strength states. It also includes all the necessary information for checking as well as design. Effects of actions, ultimate strength, safety information, and strength with and without reinforcement are also shown. CivilFEM INTRO. Essential 300

301 16.4. Axial + Biaxial Bending Design 16.4 Axial + Biaxial Bending Design 16.4 AXIAL+BIAXIAL BENDING DESIGN Process of Reinforcement Design In the design process all the scalable reinforcements are multiplied by a factor so that the safety factor of the section is as close as possible to Factor is taken from a range of values specified by the user. In case they are not specified, the program takes the configuration values: min < < max (by default ) The design process follows the steps described bellow: If the safety factor is higher than 1 for = min then min will be used. If the safety factor is less than 1 for = max then design fails. In this case, the user must either increase the initial reinforcement of the section or change max. For other cases the factor is obtained between min and max so that safety factor is within 1.00 and With CivilFEM, the results of reinforcement design are the amount of reinforcement designed and the factor for each element. CivilFEM INTRO. Essential 301

302 16.4. Axial + Biaxial Bending Design 2D Axial+Bending Design of the Reinforcement Selection of bending plane Optional stress limit min and max 3D Axial+Bending design of the reinforcement Optional stress limit min and max Reinforcement factor CivilFEM INTRO. Essential 302

303 16.5. Shear and Torsion Check and Design 16.5 Shear and Torsion Check and Design 16.5 SHEAR AND TORSION CHECK AND DESIGN CivilFEM allows following types of check and design for shear and torsion: Shear only Torsion only Combined shear and torsion The Partial Safety Factors are the code comparison criteria. For example, the torsion check according to Eurocode 2 (EN :2004/AC:2008) uses the following comparison parameters: TRDMAX (Maximum design torsional moment that can be resisted by the section without crushing of the concrete compressive struts, T Rd,max ), CRT_1 (Ratio of the design torsional moment (T Ed ) to the resistance T Rd,max ), TRD (Maximum design torsional moment that can be resisted by the torsion reinforcement, T Rd ) and CRT_2 (Ratio of the design torsional moment (T Sd ) to the resistance T Rd ) The Global Safety Factor takes into account all of the Partial Safety Factors and indicates the higher ratio of the design shear, torsional moment, or combined shear and torsional moment to the section s ultimate resistance: if it is less than 1.0, the section is valid (element is OK); whereas if it exceeds 1.0, the section is not valid (element is NOT OK). CivilFEM INTRO. Essential 303

304 16.6. Cracking Check Check results are: Elements OK and NOT OK Global safety factor Partial safety factors and results Design results are: Elements OK and NOT OK (Unable to design) Partial results Reinforcement amount 16.6 Cracking Check 16.6 CRACKING CHECK The cracking check of beam cross sections in CivilFEM is available for the following codes: Eurocode 2 ACI 318 ACI 349 (CivilFEM NPP) EHE ITER Structural Design Code for Buildings (CivilFEM NPP) It is possible to do the following types of checks: Decompression : Checks if all the internal cross section points are under compression. Cracking : Calculation of the crack width/limited stress, taking into account the bending about one of the local axes of the section. Formulation depends on the code. CivilFEM INTRO. Essential 304

305 16.7. Shell Reinforcement Check and Design 16.7 Shell Reinforcement Check and Design 16.7 SHELL REINFORCEMENT CHECK AND DESIGN Shell reinforcement works with elements SHELL43, SHELL63, SHELL93 SHELL181 and SHELL281 CivilFEM allows to design the shell reinforcement according to the following methods: Wood-Armer Method CEB-FIP Method Orthogonal Directions Method Most Unfavorable Direction Method Reinforcement amount varies in X & Y directions and in top & bottom faces for each vertex. ~DIMCON Command CivilFEM INTRO. Essential 305

306 16.7. Shell Reinforcement Check and Design Wood Method WOOD METHOD Design of reinforcement is done for MX, MY and MXY. Inplane axial and shear loads are ignored. The orientation angles of the reinforcement can be defined for each vertex. By default ALPHA= 0. My* Mx* Element axis The reinforcement design of shells under bending and torsional moments is accomplished by the Wood Method. Calculation process follows these steps: The reinforcement design moments are obtained from the acting bending moments: The bending moments Mx, My and torsional moments Mxy are provided by the shell calculation and obtained from the CivilFEM results file. Once Mx, My, and Mxy are found, a pair of design moments Mx* and My* are searched (see the picture above). These two moments are necessary for the reinforcement design and must include all the possible moments generated by Mx, My, and Mxy in any direction. Two pairs of design moments are obtained: one for the bottom reinforcement and one for top reinforcement. The limit bending moment is calculated taking into account the active code specifications. The reinforcement is calculated depending on if the design moment is greater or less than the limit bending moment. If the design bending moment is greater than the limit, both tension and compression reinforcements are disposed; otherwise only tension reinforcement is disposed. Designing results are stored in the CivilFEM results file. These results are: Reinforcement amount at X top, reinforcement amount at X bottom, reinforcement amount at Y top and reinforcement amount at Y bottom. CivilFEM INTRO. Essential 306

307 16.7. Shell Reinforcement Check and Design CEB Method CEB-FIP 1990 METHOD Design of reinforcement taking into account : Tx, Ty, Txy, Mx, My, Mxy, Nx, Ny Struts and ties model The reinforcement designing of shells under bending moment and in plane loading is accomplished by model code CEB-FIP The reinforcements take an orthogonal network (directions in this network are taken as element X and Y axes). Calculation process is based on the following: The shell is considered to be ideally divided in three layers. The outer layers provide resistance to the in plane effects of both the bending and the in plane loading; while the inner layer provides a shear transfer between the outer layers. CivilFEM INTRO. Essential 307

308 16.7. Shell Reinforcement Check and Design It assumes that the shell is reinforced with an orthogonal mesh with a x and a y separation. Therefore, the shell is divided into cells and its equivalent forces (n psdx, n psdy, v psd ) for reinforcement calculation are obtained from the acting forces and moments obtained from the CivilFEM results file. The struts and ties method is applied to determinate the reinforcement amount from the tension of the steel bars and the compression of the concrete on each cell. Two data are necessary: whether the reinforcing steel bars are braced or not and the angle between the reinforcement X axis (element X axis) and the direction of concrete compression. By default, = 45º (although it is valid any angle if 1/3 tan 3). CivilFEM INTRO. Essential 308

309 16.7. Shell Reinforcement Check and Design Orthogonal Directions Method ORTHOGONAL DIRECTIONS METHOD Reinforcement is designed under bending moments and axial forces, for the directions of the reinforcement and independently one from the other. Reinforcements are defined as an orthogonal net (directions of this net are taken as element X and Y axes). Torsional moment and membrane shear force may or may not be neglected. If they are not neglected: * T T T Sign(T ) x x xy x * T T T Sign(T ) y y xy y * M M M Sign(M ) x x xy x * M M M Sign(M ) y y xy y Where T * x and T * y are axial forces, M x and M y bending moments, and M xy torsional moment and T xy membrane shear force. CivilFEM INTRO. Essential 309

310 16.7. Shell Reinforcement Check and Design X and Y represent the orthogonal directions of bending reinforcement of the shell (Element X and Y axes) Checking results will provide the criterion for the X and Y directions independently. Design results will include the reinforcement factor for each direction, top and bottom surface. Depending on the active code, the checking or design is performed using the pivot diagram described for the check and design of concrete cross sections. The maximum allowable stress in the reinforcement can be specified in order to consider ULS cracking design. Most Unfavorable Direction Method The aim of this design method is the calculation of the reinforcement of concrete shells with a method based on the one proposed by Capra-Maury which takes into account bending moments (M xx, M yy ) and torsional moments (M xy ) as well as axial forces (N xx, N yy ) and in plane shear forces (N xy ). MOST UNFAVORABLE DIRECTION METHOD A group of top (Axt, Ayt) and bottom (Axb, Ayb) reinforcements will be obtained balancing the bending moment and axial force (M, N) projected on a plane with its normal contained in the shell. To solve it, the total bottom reinforcement and the total top reinforcement are minimized independently. Reinforcements are considered to be orthogonal and set along the X and Y axes of the element. Considering a plane with its normal contained in the shell and located at an angle from the positive X axis of the element, the bending moment and axial force (M, N) are: CivilFEM INTRO. Essential 310

311 16.7. Shell Reinforcement Check and Design M() = M xx cos 2 + M yy sin 2 - M xy sin 2 N() = N xx cos 2 + N yy sin 2 - N xy sin 2 From these values, the required reinforcements A t and A b are calculated. The following conditions must be fulfilled A xt cos 2 + A yt sin 2 A t A xb cos 2 + A yb sin 2 A b π 2 θ Depending on the active code, the check or design is performed using the pivot diagram for beams, one for each direction. Checking results will provide the total criterion and the axial force N(θ) and bending moment M(θ) are used to obtain this criterion. Design results will include the reinforcement area for each direction, top and bottom surfaces. The maximum allowable stress in reinforcement can be specified in order to consider ULS cracking design. π 2 CivilFEM INTRO. Essential 311

312 16.8. Results Shear SHEAR In shear check or design, the reinforcement is designed under an equivalent shear force: V V V 2 2 x y It will be calculated according to the criteria of the selected code. The design shear force is the composition of the shear forces in each direction of the shell Results Checking results are stored in Alternatives. The RCV results file will store the solved load steps and substeps, and the alternatives obtained by code check or design. In order to postprocess the code results, it is necessary to point at the desired alternative, not the load step. CivilFEM INTRO. Essential 312

313 16.8. Results 16.8 RESULTS BEAM RESULTS Partial results of the calculation according to the selected code Total criteria Elements OK and NOT OK Reinforcement amount or scaling factor (design) SHELL RESULTS An icon shows the reinforcement location CivilFEM INTRO. Essential 313

314 CivilFEM INTRO. Essential Results

315 17 CivilFEM Steel Checking CivilFEM INTRO. Essential 315

316

317 17.1. General concepts 17.1 General concepts 17.1 General Concepts With CivilFEM it is possible to accomplish steel code checks according to the different design codes for steel structures. It is possible to check any crosssection defined using any of the CivilFEM available methods, including the cross-sections defined by plates. CivilFEM has the following codes implemented: Eurocode 3 CTE DB SE-A (Spanish) EA-95 (Spanish) AISC-LRFD 2 nd Edition AISC-LRFD 13 th Edition AISC-ASD 13 th Edition AISC-ASD 9 th Edition (CivilFEM NPP) British Standard 5950 (1985 & 2001) GB50017 (Chinese) ASME BPVC Sect.III Div.1 SubSection NF (1989) (CivilFEM NPP) ANSI/AISC N (CivilFEM NPP) ANSI/AISC N ASD and LRFD provisions (CivilFEM NPP) Each code uses different criteria and methods as shown hereafter. CivilFEM INTRO. Essential 317

318 17.2. Eurocode Eurocode 3 Eurocode 3 Types of checking Tension (1D): FX+ Compression (1D): FX- Bending (2D): MZ or MY Shear (2D): FY or FZ Bending + shear (2D): (FY, MZ) or (FZ, MY) Bending + Axial (3D): FX, MY, MZ Y Y Z G.C. Z Y Bending + Axial + Shear (3D): FX, FY, FZ, MY, MZ Compression Buckling (1D): FX- Lateral Buckling (2D): MZ or MY Lateral Buckling in Bending + Tension (3D): FX+, (MY or MZ) Buckling in Bending + Compression (3D): FX-, MY, MZ Z For studying the safety of the structure, Eurocode 3 classifies sections in 4 possible classes: Class 1 Class 2 Class 3 Class 4 Cross-sections that can form a plastic hinge with the rotation capacity required for plastic analysis. Cross-sections that can reach their plastic moment resistance, but have limited rotation capacity. Cross-sections in which the stress in the extreme compression fiber of the steel member can reach its yield strength, but local buckling is liable to prevent development of the plastic moment resistance. Cross-sections in which it is necessary to make explicit allowances for the effects of local buckling when determining their moment resistance or compression resistance. CivilFEM INTRO. Essential 318

319 17.2. Eurocode 3 Class 1 Mu = f y * W plastic It can form a plastic hinge Class 3 Mu = f y * W elastic Only elastic solutions Class 2 Mu = f y * W plastic Limited rotation capacity Class 4 Mu < f y * W elastic Only elastic solutions Compact Sections Slender Sections Class 1 Class 2 Class 3 Class 4 In class 4 sections, the section resistance is reduced: for each section plate, the effective lengths at both ends of the plate and the reduction factors 1 and 2 are calculated. Class 4 section Axis selection Plot options Selection of the section to plot Non-effective segment The program takes into account the reduction in the resistance of slender sections (class 4) due to local buckling. Section forces and moments list Plates list CivilFEM considers and works with three different coordinate reference systems. All of these systems are right-handed: CivilFEM INTRO. Essential 319

320 17.2. Eurocode 3 1. CivilFEM Reference Axis. (blue axis). 2. Cross-Section Reference Axis. (pink axis). 3. Eurocode 3 Reference Axis. (Code axis). (green axis). To define the Eurocode 3 reference system, the user must indicate which of the CivilFEM axis: -Z, -Y, +Z or +Y coincides with the relevant axis for positive bending. Specify the main axis for bending Class Calculation Class Calculation: Partial: Check only takes into account the forces and moments corresponding to the check being executed. Full: Check takes into account all forces and moments. Notes According to Eurocode 3, CivilFEM checks: Section resistance Local buckling of the section plates Element buckling with the method Results and safety factors depend on the selected axis for the check. Eurocode 3 changes its sign criteria according to the two cases: In compression checking, compression is taken as positive. In tension checking, tension is taken as positive. CivilFEM INTRO. Essential 320

321 17.3. EA EA-95 EA-95 Types of Checks: Tension (1D): FX+ Compression (1D): FX- Bending (2D): MZ or MY 17.4 BS 5950 BS 5950 (1985 and 2001) Types of Checks: Y Y Y Z Z G.C. X Bending + Shear (2D): (FY, MZ) or (FZ, MY) Lateral Buckling (2D): MZ or MY Tension (1D): FX+ Compression Buckling (1D): FX- Bending + Tension + Shear (3D): FX, FY, FZ, MY, MZ Bending + Compression + Shear (3D): FX, FY, FZ, MY, MZ CivilFEM INTRO. Essential 321

322 17.4. BS 5950 CivilFEM, when performing checks according to BS 5950, considers and works with three different coordinate systems. All of these systems are right-handed: 1. CivilFEM Reference Axis (blue axis). 2. Cross-Section Reference Axis (pink axis). 3. BS 5950 Reference Axis (Code Axis), (green axis). Y Y Y Z Z G.C. X Specify the main axis for bending To define this reference system, the user must indicate which direction of the CivilFEM axis: -Z, -Y, +Z or +Y coincides with the relevant axis for positive bending. The steps for the checking process are as follows: 1. Read the checking type requested by the user. 2. Read the CivilFEM axis to be considered as the principal bending axis in order to coincide with the X-axis of BS Checking operations for each element: Obtain material properties stored in the CivilFEM database corresponding to the element and calculate the rest of the properties needed for checking: Shear Modulus, Epsilon (material coefficient). Obtain the cross-section data corresponding to the element. Determine of the section class (similar classification to Eurocode 3) and calculate the reduction factors applied to the design strength in the case of slender sections. Obtain forces acting on the section (Fx, Fvx, Fvy, Mx, My). CivilFEM INTRO. Essential 322

323 17.5. AISC-LRFD and ASIC-ASD Check the specific section according to the type of external load. Document the results which will be stored in the CivilFEM results file (.RCV) as an alternative AISC-LRFD and ASIC-ASD AISC-LRFD (2 nd Edition) Types of Checks: Tension Compression for flexural buckling Compression for flexural-torsional buckling Bending Shear Plate Girders Bending + Axial Bending + Axial + Shear + Torsion AISC-ASD (9 th Edition) Types of Checks: Tension Compression for flexural buckling Compression for flexural-torsional buckling Bending Shear Axial compression + Bending Axial tension + Bending CivilFEM INTRO. Essential 323

324 17.5. AISC-LRFD and ASIC-ASD AISC-LRFD and AISC-ASD (13 th Edition) Types of Checks: Tension Compression for flexural buckling Compression for flexural-torsional buckling Bending Shear Plate Girders Bending + Axial Bending + Axial + Shear + Torsion CivilFEM INTRO. Essential 324

325 17.6. ANSI/AISC N ANSI/AISC N690 ANSI/AISC N ASD and LRFD provisions Types of Checks: Tension Compression for Flexural Buckling Compression for Flexural-Torsional Buckling Bending Shear Plate Girders Bending + Axial Bending + Axial + Shear + Torsion ANSI/AISC N Types of Checks: Tension Compression for Flexural Buckling Compression for Flexural-Torsional Buckling Bending Shear Axial Compression + Bending Axial Tension + Bending CivilFEM INTRO. Essential 325

326 17.7. GB GB50017 GB50017 Types of Checks: Bending Shear Bending + Shear Axial Force Bending + Axial Compression Buckling 17.8 CTE DB SE-A CTE DB SE-A Types of Checks: Tension Compression Bending Shear Bending + Axial Force Bending + Shear Bending + Axial Force + Shear Compression Buckling Bending Buckling Bending + Tension Buckling Bending + Compression Buckling CivilFEM INTRO. Essential 326

327 17.9. ASME BPVC Section III Div.1 SubSection NF (1989) 17.9 ASME BPVC Section III Div.1 SubSection NF (1989) ASME BPVC Sect. III Div.1 SubSection NF (1989) Types of Checks: Tension Shear Compression Bending Bending + Axial Compression Bending + Axial Tension CivilFEM INTRO. Essential 327

328

329 18 CivilFEM Envelopes CivilFEM INTRO. Essential 329

330

331 18.1. Alternatives and Envelopes 18.1 Alternatives and Envelopes The data in the CivilFEM results file are stored in two different types of data blocks: blocks of stresses, forces, moments, and strains and blocks of alternatives. Data blocks of stresses, forces, moments, and strains are obtained and stored immediately after solving. Blocks of alternatives differ from each other in their content because they depend on the process (type of check or design) that has generated the alternative. These data are created in postprocessing phase, taking input data of forces, moments, stresses, and strains from the corresponding blocks. Each block of forces, moments, stresses, and strains may generate one or more alternative blocks Alternatives and Envelopes This utility allows the generation of new alternatives as an envelope of others previously obtained. There are three types of envelopes: maximum values, minimum values, and absolute values. Envelopes have to be homogeneous: each must be obtained by the application of the same code and the processing of the same model. The resulting alternative will be homogeneous with the previous ones, possessing a similar identification and the same reading, drawing and representation commands. RCV.File Stresses Strains Forces Moments Alternative 1 Alternative 2 ~ENVELOP RCV.File Stresses Strains Forces Moments Alternative 1 Alternative 2 Alternative 3 The envelope of several alternatives is a new data block (new alternative) that contains the minimum, maximum or absolute maximum values (depending on type) of each input alternatives. CivilFEM INTRO. Essential 331

332

333 19 CivilFEM Seismic Design CivilFEM INTRO. Essential 333

334

335 19.1. Time or Frequency Domain? 19.1 Time or Frequency Domain? 19.1 Time or Frequency Domain? Time All Types of Analysis - Non Linear - Any Damping Easy Concepts - Few concepts differ from a static analysis Difficult Calculation - Calculation time is high - Disc space needed is high Frequency Valid for Some Analyses - Linear Analysis - Simplified Damping New Concepts - Mode shapes - Spectrum, Eigenvalues Easy Calculation Better phenomena comprehension 19.2 Frequency Domain 19.2 Frequency Domain Modal Analysis This method allows the user to obtain the natural frequencies and mode shapes of a structure. It functions well as a first evaluation, but sometimes is insufficient. Harmonic Analysis Useful when actions are cyclic, have the same frequency and act indefinitely. Spectral Analysis by Modal Superposition The response of the structure is characterized by the combination of some of the natural mode shapes of the structure, multiplied by a coefficient that comes from the spectrum. CivilFEM INTRO. Essential 335

336 19.3 What is a Spectrum? What is a Spectrum? 19.3 What is a Spectrum? Acceleration Spectrum for a certain location A spectrum is a function that shows the maximum response of a system of simple oscillators with a specific damping under a dynamic action. Usually, the X-axis contains frequencies or periods and the Y-axis, displacements, velocities or accelerations. Normally, a 5% damping is a good estimate Modal Analysis 19.4 Modal Superposition Analysis The solicitation is given in terms of spectra (accelerations). The analysis consists of evaluating the structure s behavior as the sum of the responses of each of its mode shapes. The response of each one of these natural mode shapes is obtained from the data given by the spectrum for the specific frequency, multiplied by the modal participation factor. This factor takes into account how much the orientation of the solicitation excites every mode. CivilFEM INTRO. Essential 336

337 19.5. Seismic Design 19.5 Seismic Design 19.5 Seismic Design CivilFEM provides a set of tools that allow for a simple analysis of forces and moments due to seismic action in structures according to the following codes: Eurocode 8 NCSE (Spanish code 94 and 02) IT 3274 (Italian code) The Greek code EAK 2000 The French code PS 92 Chinese code GB50011 CALTRANS Seismic Design Criteria AASHTO LRFD Bridge Design Specifications Uniform Building Code (1997) Indian Standard 1893 Elements available: All elements CivilFEM INTRO. Essential 337

338 19.5. Seismic Design CivilFEM builds and defines the response spectrum from a certain code with the parameters that define it. The data required to define the response spectrum are input into the CivilFEM database with the ~DEFSPEC command. Four spectra can be defined for different damping values. Up to four spectra may be defined with different damping ratios. Each of the spectra may be created using different code options, but only the last ones used will be listed. It is also possible to define the spectra by points: First, the periods must be defined in ascending order. Then, for each of the damping values, different accelerations can be provided to define the different spectra. CivilFEM INTRO. Essential 338

339 19.5. Seismic Design The procedure to define the spectra by points is: Define the horizontal periods in ascending order. Next, the horizontal acceleration values may be defined for the previously set periods. Up to four spectra may be defined, each one for a different damping value. All of these spectra have the same period table. Define the vertical periods in ascending order. For the vertical period table, the vertical acceleration values may be defined in the same way as for the horizontal values. The number of modes to be extracted can be defined with the command ~MODLSOL. The default is 20 modes. The number of mode shapes to be calculated is taken as input data for the modal analysis of the structure that is carried out in ANSYS. CivilFEM INTRO. Essential 339

340 19.5. Seismic Design Both the abscissas and ordinates of the spectrum can be listed and plotted with the commands ~L_SPEC and ~P_SPEC. Spectrum component to be drawn Initial period Final period Increments CivilFEM INTRO. Essential 340

341 19.5. Seismic Design Modes Combination Once the vibration modes are obtained by means of the ~CMBMOD command, they are combined in the indicated directions. The combination of vibration modes can be done with the command ~CMBMOD. To use this command, the spectrum data must be defined and the vibration modes to be combined extracted. The combination result is stored in CivilFEM s results file (file.rcv) with a Load Step number following the last Load Step carried out. CivilFEM INTRO. Essential 341

342 19.5. Seismic Design The result of the combination of modal responses, is stored in CivilFEM as Loadstep 2 (Modal analysis is stored in Loadstep 1). Therefore, to visualize results, use the ~CFSET command to point to this Loadstep. *** CivilFEM DATASET *** LOADSTEP SUBSTEP CUMULATIVE *** ALTERNATIVES IN.RCV FILE *** DATASET STATUS: NUMBER OF ALTERNATIVES: 0 CURRENT ALTERNATIVE NUMBER: 0 CURRENT LOADSTEP: 0 CURRENT SUBSTEP: 0 If the combination method is SRSS, for each one of the three directions (longitudinal, transversal and vertical), the result combination for the different vibration modes is the square root of the sum of the considered variables squares. Once the significant vibration modes are combined in each of the three directions (longitudinal, transversal and vertical), the result is again the square root of the sum of the squares. For the rest of combination methods (CQC, DSUM, GRP y NRLSUM), it is only possible to apply the spectrum and combine the vibration modes in the selected direction. CivilFEM INTRO. Essential 342

343 19.6. Push Over Analysis 19.6 Push Over Analysis 19.6 Push-Over Analysis The model of the structure surrenders to a lateral load which increases depending on a certain parameter. The figure shows a structure, in this case a lighthouse, subjected to a certain vertical load W (self weight + other loads) and to a lateral wind load. As a consequence of this action and the intensity, determined by the value of a certain parameter (in this case represents the value of the pressure at the top of the structure), the structure suffers a deformation that is measured by the displacement of the highest point and a horizontal reaction on the base: δ roof (λ) V() On a Cartesian chart, the pair of values ( roof, V) is plotted to obtain the capacity or V- curve. Interesting points on this graph for the structure can be observed, such as at the end of the elastic behavior or at the beginning of the collapse process. Next, a modal analysis of the structure is performed and the k-th vibration mode with the highest participation factor PF is obtained (it is normally the first one, k=1, except when local modes are present). The following magnitudes are then defined: CivilFEM INTRO. Essential 343

344 19.6. Push Over Analysis PF k N i1 N i1 m m i i ik 2 ik (Modal Mass Coefficient) i ik i1 k N N 2 m i m i ik i1 i1 α N m 2 (Modal Participation Factor) In these expressions ik is the i-th component of the vibration mode k, and m i is the mass that corresponds to the associated degree of freedom. The vibration modes are normalized, so that: N 2 m i ik 1 (N = total number of degrees of freedom) i1 The previous expressions are simplified: N PF m k i ik i1 2 PFk α k (W/g) To carry out the Push Over analysis, a change of variables is made from the roof V diagram built before, to a new S d S a diagram called Acceleration- Displacement Response Spectrum or ADRS. The change of variables is S S a d V W k k δroof PF. k,roof Both curves can be seen in the previous figure. The following figure shows usual values of the previously defined parameters for different shapes of the dominant vibration mode k. CivilFEM INTRO. Essential 344

345 19.6. Push Over Analysis Therefore: Response spectra are usually set in terms of accelerations (S a ), pseudovelocities (S v ) or displacements (S d ) corresponding with the vibration period T. Between these four magnitudes, the following relationships can be set when S a is expressed as fractions of g. 2π T S g = S, S S T 2π a v d v Removing S v from the previous expressions, the following equation is obtained: S d 2 T 4π This equation sets the relationship between the acceleration and displacements spectra. The following figure represents the acceleration spectra in its standard expression (T, Sa), and from this figure, the (S d, S a ) spectra ADSR is obtained. 2 g S a CivilFEM INTRO. Essential 345

346 19.6. Push Over Analysis S a (x g) S = T 2 g d 2 S a Standard Format Spectrum T ZPA (Rigid body acceleration) S a (x g) T=T 1 T=T 2 T=T 3 ADRS Format Response Spectra S d S d /S a = c, (constant) The lines depicted through the origin represent, in this plane, the locus of an equal vibration period: T = 2π Sd g S a 2π With lower values of T, the structure is stiffer. In fact, the value of S a for T = 0 is known as ZPA (zero period acceleration), so the value 1 S k c S for these straight lines is a measure of the stiffness. a d c g CivilFEM INTRO. Essential 346

347 19.6. Push Over Analysis Superposing the Capacity Spectrum Curves (CSC) and the Demand Spectrum Curve (DSC) with (Sd, Sa) axes obtains the following graph: Elastic Point Capacity Spectrum Curve Inelastic Point (IP) Performance Point (PP) Demand Spectrum Curve Superposing the Capacity Spectrum curve with the Demand Spectrum Curve in the (Sd, Sa) graph. If the structure remains elastic during the entire load process, the intersection point of the CSC and DSC curves (capacity and demand), known as the Performance Point (PP), represents the equilibrium situation. This is to say, pp would be the deformation that would be obtained when the seismic forces act on the structure. Nevertheless, in general, the structure does not remain in an elastic regime during the whole process. For this reason, several authors prefer to consider the Inelastic Point (IP) as a working point in presence of seismic forces, obtained as shown in the previous figure. It is therefore equivalent to conclude that when regarding displacements, the structure maintains its elastic behaviour until its intersection with the demand curve. During the process, plastic local phenomena take place which cause the weakening of the structure. For example: a load applied to a structure is increased by a multiplier factor i ( i > j if i > j). CivilFEM INTRO. Essential 347

348 19.6. Push Over Analysis 1 ( x 1 ) B D x 2 x 3 x 4 x 5 P Q A C Elastic behaviour Plastic behaviour S a (x g) T=T 1 T=T I T=T PP (Performance Point) 2 5 T=T 3 1 Retrofit Analysis S d If < 2 the structure stays elastic with a stiffness that is determined by the straight line corresponding to the period T = T I. If = 2 the PC bar becomes plastic. If = 4 the structure is weakened because both the AP and PC bars have undergone yielding. If = 5 the structure collapses. With this analysis it is possible to determine where the structure needs to be strengthened. The Push Over analysis consists of several steps: 1. Creation of the finite element model. 2. Response Spectrum and modal analysis. 3. Definition of the vertical loads which remain constant during the process. 4. Definition of the horizontal loads that will be increased by the parameter. These loads are stored in a load file (~CFLSWRT command). 5. Definition of a range for the parameter: ( i, f ) and the increment. (~PUSHDEF command) 6. Selection of the predominant mode. (~PUSHMOD command). CivilFEM INTRO. Essential 348

349 19.6. Push Over Analysis 7. Calculation of the structure submitted to the loads defined in 3 and 4, changing (~PUSHSLV command). 8. Selection of a stage (across Sd or ) and a graphic representation (~RETROFT command). The results can be listed using the ~PUSHLST command. General Data Number of node Coordinates of node Load state file Load multiplier factor Number of substeps Vertical axis ~PUSHDEF command Disp. Measure Point: The Push Over curves will be defined with the displacement found at this point. It may be defined by node coordinates or by the node number. LS File: Load state file that contains the loads placed on the structure that will be increased by the multiplier factor. Lambda: load multiplier factor. SS num: Number of substeps. For every substep, the load will be increased by / SS num. (For example, if there are 10 substeps and =5, 1 =0.5 2 = 1 3 = =5, then the load is multiplied by 1 in the first load state, by 2 in the second load state, etc ) Vertical Axis: A vertical axis must be defined (direction of gravity). CivilFEM INTRO. Essential 349

350 19.6. Push Over Analysis Modal Shape Selected mode shape Solve (~PUSHMOD and ~PUSHSLV commands) Curves Performance Point Inelastic Point Elastic Point Lambda or Sd Values Plot (~RETROFT Command) PP (performance point): Intersection point of the curves. EP (elastic point): Intersection point of the curves if the structure had an elastic behaviour. IP (inelastic point): Point of the capacity curve vertically above the EP. After introducing the values of Sd or the multiplier factor Lambda in the RETROFIT area of the window, the yielding of the structure is represented in the graphic window for a specific substep. CivilFEM INTRO. Essential 350

351 19.6. Push Over Analysis Yielded elements Through commands this can be done by entering: ~RETROFIT, Lambda, VALUE Or ~RETROFIT, Sd, VALUE ~RETROFT, Lambda, VALUE to view the yielding of the structure for each substep. CivilFEM INTRO. Essential 351