m Al ple lc p op ro yi vid ng e d an b d ya re S us C e EN st T ric fo tly r fo rev rb ie id w de o n. nly Sa Part 1 Seminar Notes
II Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
2015 Autodesk, Inc. All rights reserved. Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes Except as otherwise permitted by Autodesk, Inc., this publication, or parts thereof, may not be reproduced in any form, by any method, for any purpose. Certain materials included in this publication are reprinted with the permission of the copyright holder. Trademarks The following are registered trademarks or trademarks of Autodesk, Inc., and/or its subsidiaries and/or affiliates in the USA and other countries: 123D, 3ds Max, Algor, Alias, AliasStudio, ATC, AutoCAD LT, AutoCAD, Autodesk, the Autodesk logo, Autodesk 123D, Autodesk Homestyler, Autodesk Inventor, Autodesk MapGuide, Autodesk Streamline, AutoLISP, AutoSketch, AutoSnap, AutoTrack, Backburner, Backdraft, Beast, BIM 360, Burn, Buzzsaw, CADmep, CAiCE, CAMduct, CFdesign, Civil 3D, Cleaner, Combustion, Communication Specification, Constructware, Content Explorer, Creative Bridge, Dancing Baby (image), DesignCenter, DesignKids, DesignStudio, Discreet, DWF, DWG, DWG (design/logo), DWG Extreme, DWG TrueConvert, DWG TrueView, DWGX, DXF, Ecotect, ESTmep, Evolver, FABmep, Face Robot, FBX, Fempro, Fire, Flame, Flare, Flint, FMDesktop, ForceEffect, FormIt, Freewheel, Fusion 360, Glue, Green Building Studio, Heidi, Homestyler, HumanIK, i-drop, ImageModeler, Incinerator, Inferno, InfraWorks, Instructables, Instructables (stylized robot design/logo), Inventor LT, Inventor, Kynapse, Kynogon, LandXplorer, Lustre, MatchMover, Maya, Mechanical Desktop, MIMI, Mockup 360, Moldflow Plastics Advisers, Moldflow Plastics Insight, Moldflow, Moondust, MotionBuilder, Movimento, MPA (design/logo), MPA, MPI (design/logo), MPX (design/logo), MPX, Mudbox, Navisworks, ObjectARX, ObjectDBX, Opticore, Pipeplus, Pixlr, Pixlr-o-matic, Productstream, RasterDWG, RealDWG, ReCap, Remote, Revit LT, Revit, RiverCAD, Robot, Scaleform, Showcase, ShowMotion, Sim 360, SketchBook, Smoke, Socialcam, Softimage, Sparks, SteeringWheels, Stitcher, Stone, StormNET, TinkerBox, ToolClip, Topobase, Toxik, TrustedDWG, T-Splines, ViewCube, Visual LISP, Visual, VRED, Wire, Wiretap, WiretapCentral, XSI Microsoft and Windows are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries. NASTRAN is a registered trademark of the National Aeronautics and Space Administration. SolidWorks is a registered trademark of Dassault Systèmes SolidWorks Corporation. All other brand names, product names or trademarks belong to their respective holders. Disclaimer THIS PUBLICATION AND THE INFORMATION CONTAINED HEREIN IS MADE AVAILABLE BY AUTODESK, INC. "AS IS." AUTODESK, INC. DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE REGARDING THESE MATERIALS. Published by: Autodesk, Inc. 111 Mclnnis Parkway San Rafael, CA 94903, USA Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 III
IV Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
TABLE OF CONTENTS Introduction... 1 Overview...1 Software Installation, Services, and Support...1 Installing and Running Autodesk Simulation Mechanical...1 System Requirements...2 Autodesk Simulation Mechanical Help...2 InfoCenter...4 Web Links...4 New User Quick Start...5 Tutorials...5 Autodesk Knowledge Network...5 Autodesk Simulation TV...5 How to Receive Technical Support...5 Updates...6 Background of FEA...7 What is Finite Element Analysis?...7 Basic FEA Concepts...7 How Does Autodesk Simulation Mechanical Work?... 10 The General Flow of an Analysis in Autodesk Simulation Mechanical... 10 Stress and Strain Review... 11 Equations Used in the Solution... 11 Limits of Static Stress with Linear Material Models... 12 Mechanical Event Simulation (MES) Overcomes Limitations... 12 Hand-Calculated Example... 13 Heat Transfer Review... 13 Equations Used in the Solution... 13 Linear Dynamics Review... 14 Equation for Dynamic Analyses... 14 Chapter 1: Using Autodesk Simulation Mechanical... 15 Chapter Objectives... 15 Navigating the User Interface... 15 Commands... 17 Using the Keyboard and Mouse... 18 Introduction to the ViewCube... 19 Additional View Controls The Navigation Bar... 20 Legacy View Controls in Autodesk Simulation Mechanical... 22 Steel Yoke Example... 22 Opening and Meshing the Model... 23 Setting up the Model... 24 Analyzing the Model... 28 Reviewing the Results... 28 Viewing the Displaced Shape... 29 Creating an Animation... 29 Generating a Report... 29 Chapter 2: Static Stress Analysis Using CAD Solid Models... 33 Chapter Objectives... 33 Archiving a Model... 33 Types of Brick Elements... 34 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 VII
Table of Contents Generating Meshes for CAD Models... 35 Creating a Mesh... 36 Model Mesh Settings Options... 37 Tips for Modeling for FEA with CAD Solid Modelling Software... 39 Simplify CAD Solid Models with Autodesk SimStudio Tools... 40 Working with Various Unit Systems... 41 Loading Options... 42 Load Cases... 44 Constraint Options... 45 Modeling Symmetry and Antisymmetry... 46 Design Scenarios... 47 Load and Constraint Group... 48 Local Coordinate Systems... 49 Defining Materials and Using the Material Library Manager... 50 Adding Material Libraries and Material Properties... 52 Examples of Loads and Constraints... 54 When to Use Displacement Boundary Elements... 54 Using Local Coordinate Systems... 54 Using Surface Variable Loads... 58 Exercise A: Frame Full to Quarter-Symmetry Model Comparison... 63 Chapter 3: Results Evaluation and Presentation... 65 Chapter Objectives... 65 Background on How Results are Calculated... 65 How to Evaluate Results... 66 Displacement Results... 66 Stress Results... 68 Reaction Force Results... 70 Inquiring on the Results at a Node... 70 Graphing the Results... 71 Presentation Options... 73 Contour Plots... 73 Image File Creation... 77 Animating FEA Results... 78 Using the Configure Report Utility... 79 Exercise B: Yoke Evaluation of Results and Generation of a Report... 81 Chapter 4: Midplane Meshing and Plate Elements... 83 Chapter Objectives... 83 Meshing Options... 83 Element Options... 87 Plate Theory and Assumptions... 87 Loading Options... 88 Example of Defining the Element Normal Point... 89 Result Options... 92 Exercise C: Midplane Meshing and Plate Element Orientation... 93 Chapter 5: Meshing... 95 Chapter Objectives... 95 Refinement Options... 95 Automatic Refinement Points... 95 Global Refinement Options... 97 VIII Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Table of Contents Creating Joints... 99 Creating Bolts... 101 Mesh Convergence Testing... 103 Performing a Mesh Study... 104 Exercise D: Yoke and Clevis Assembly... 105 Chapter 6: Introduction to Contact... 107 Chapter Objectives... 107 Uses for Contact... 107 Contact Options... 107 Setting up Contact Pairs... 107 Types of Contact... 108 Surface Contact Direction... 111 Contact Example... 112 How to Model Shrink Fits:... 112 Shrink Fit Example... 113 Case 1 Shrink Fit / No Sliding... 114 Case 2 Shrink Fit / Sliding... 117 Result Options... 118 Exercise E: Yoke Assembly with Contact... 119 Chapter 7: Introduction to Linear Dynamics... 121 Chapter Objectives... 121 Modal Analysis... 121 Weight... 122 Load Stiffening... 123 Example of Natural Frequency (Modal) Analysis... 124 Meshing the Model... 125 Adding Constraints... 126 Defining the Materials... 126 Analyzing the Model... 126 Reviewing the Results... 126 Critical Buckling Analysis... 127 Setting Up a Critical Buckling Analysis... 128 Result Options... 129 Other Linear Dynamics Analyses... 129 Exercise F: Concrete Platform... 131 Chapter 8: Steady-State Heat Transfer... 133 Chapter Objectives... 133 3-D Radiator Example... 133 Meshing the Model... 134 Setting up the Model... 135 Analyzing the Model... 136 Reviewing the Results... 136 Meshing Options... 137 Thermal Contact... 137 Element Options... 139 Rod Elements... 139 2-D Elements... 139 Plate Elements... 140 Brick and Tetrahedral Elements... 141 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 IX
Table of Contents Loading Options... 143 Nodal Loads... 143 Surface Loads... 145 Element Loads... 150 Body-to-Body Radiation... 152 Controlling Nonlinear Iterations... 155 Result Options... 157 Exercise G: Infrared Detector Model... 159 Chapter 9: Transient Heat Transfer... 161 Chapter Objectives... 161 When to Use Transient Heat Transfer... 161 Element Options... 161 Loading Options... 162 Load Curves... 162 Controlling Nodal and Surface Controlled Temperatures... 163 Result Options... 164 Exercise H: Transistor Case Model... 165 Chapter 10: Thermal Stress... 167 Chapter Objectives... 167 Multiphysics Overview... 167 Performing a Thermal Stress Analysis... 168 Exercise I: Disk Brake Rotor Heat-up and Stress... 171 Appendix A Finite Element Method Using Hand Calculations... 173 Model Description and Governing Equations... 175 Hand-Calculation of the Finite Element Solution... 177 Autodesk Simulation Mechanical Example... 178 Appendix B Analysis Types in Autodesk Simulation Mechanical.. 181 Background on the Different Analysis Types... 183 Choosing the Right Analysis Type for Your Application... 189 Combining Analysis Types for Multiphysics Scenarios... 192 Appendix C Material Model Options... 193 X Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Introduction Overview This course will introduce you to the analysis products available within the Autodesk Simulation Mechanical software. These capabilities include static stress with linear material models, heat transfer, and linear dynamics analyses. The course will focus exclusively on models originating from CAD solid modeling programs. You will learn the various meshing options available for creating solid and plate elements. The available load and constraint options for each of the covered analysis types will also be presented. You will learn how to evaluate the results of the analyses and how to create presentations of the results, including images, animations and HTML reports. This course is a prerequisite to the more advanced topic of Mechanic Event Simulation (MES) covered in the Part 2 training seminar. Software Installation, Services, and Support Installing and Running Autodesk Simulation Mechanical The simulation software is distributed on DVDs. In addition, the software may be downloaded from the Autodesk website. When you place the software DVD into a DVD- ROM drive, a launch dialog box having four options will appear. If the installer does not launch automatically, navigate to the root folder on the DVD-ROM disk and run Setup.exe. Wait a few moments for the setup initialization to complete. If you want to set up the software on a client workstation, whether you will be using a standalone license or a network license, click the "Install" button. If using a network license, you must already have the license server software installed on a computer on the network. If you wish to create pre-configured deployments for installing the product on multiple client workstations, choose the "Create Deployment" command. If you want to set up the computer as a license server to control the number of concurrent users through a network, or if you wish to install optional reporting tools, click the "Install Tools and Utilities" command. Finally, the following additional commands are available: Installation Help: Accesses the Autodesk Installation Help. Cross-product information regarding the installation process, network administration, and licensing, is available here. In addition, there is a product supplement that covers additional installation topics specific to Simulation Mechanical. System Requirements: Leads to the Simulation Mechanical system requirements page on the Autodesk website. Readme: Leads to the Readme subpage of the Autodesk Simulation Mechanical documentation webpage. The Readme is available in several languages. This document includes installation requirements and a summary of known software issues. During the installation process, you must accept a license agreement. For the desktop version, choose the license type (stand-alone or network) and enter the product serial number and the product key otherwise, you will be limited to a 30-day trial period. For the Flex (cloudcomputing) version, no serial number or code is required. Instead, you are prompted for your username and password when you first launch the program. Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 1
Introduction By default, Autodesk SimStudio Tools 2016 is installed along with Simulation Mechanical 2016. You can deselect SimStudio Tools to prevent it from being installed. However, this is not recommended because an Edit: SimStudio Tools command is provided within the Simulation Mechanical Tools tab of the ribbon. Use this command to modify CAD geometry in SimStudio Tools regardless of the source of the CAD data. To customize the installation location on your computer, type in the desired "Installation Path," or click the "Browse" button to navigate to the desired parent folder on your hard drive. A Simulation 2016 subfolder is created within the parent folder you specify and the software is installed there. In addition, a SimStudio Tools 2016 subfolder is created for the installation of that product, unless you choose not to install it. Any time after the installation, you will be able to start the software by using the found in the "Start" menu folder, "All Programs: Autodesk: Autodesk Simulation Mechanical..." The version number is included in the start menu folder name and the shortcut. In the dialog box that appears when the program is launched, you will be able to open an existing model or begin a new model. The simulation software will be used to create, analyze, and review the results of an analysis within a single user interface, regardless of the analysis type. System Requirements Consult the system requirements webpage for the latest information regarding the recommended or minimum hardware and operating systems for running Simulation Mechanical. Use the link provided in the program installer or navigate to the following page using your web browser: http://autodesk.com/sim-systemreq-2016-enu Autodesk Simulation Mechanical Help Simulation Mechanical Help is available via an online Help website. This resource contains the following information: What's New: A new feature list for the three most recent program versions. New User Quick Start: Videos and tutorials specifically designed with the new user in mind. Essential Skills videos * Meshing, modeling, and analysis tutorials Comprehensive User's Guide containing documentation for the following topics o FEA fundamentals o Model import and creation options o Description & setup for available analysis types o Modeling and analysis examples o User interface o Meshing o Result evaluation and reports Autodesk Fatigue Wizard Autodesk Vault Basic Add-In Installation and Licensing Guides and Simulation Mechanical Installation Supplement NOTE: For those without Internet access at their workstation, or with a slow Internet connection, a local help installer is available from the webpage http://www.autodesk.com/simulation-documentation Download and run the appropriate installer, following the instructions provided on the same webpage. The program will use the online Help when an Internet connection is available and will use the locally installed help when not connected to the Internet. * Essential Skills videos are not included within the local help. These must be watched from the online Help. 2 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Introduction How to Access the Help Files Select the "Start and Learn" tab. Click on the "Help" command in the Learn panel of the ribbon. The homepage of the Autodesk Simulation Mechanical Help will appear. m Al ple lc p op ro yi vid ng e d an b d ya re S us C e EN st T ric fo tly r fo rev rb ie id w de o n. nly Alternatively, click on the question mark icon within the InfoCenter (see page 4) to access the same Help homepage. Type one or more keywords into the search field within the InfoCenter (see page 4) to search the online Help contents. A webpage showing the resultant search hits will display in your web browser. NOTE: You can navigate through the online Help via the Table of Contents frame on the left half of the webpage, or by entering keywords in the Search tab. For locally installed help, a navigation frame appears along the left side of the browser window. This frame includes Contents, Index, and Search tabs for convenient help topic navigation. Features of the Online Help We all learn differently, Autodesk online Help accommodates these differences by offering content in an array of formats including video instructions, tutorials, examples, and articles. To make this wide assortment of information available, the online Help search tool extends beyond the core help content, automatically searching the Autodesk support knowledgebase, discussion forums, blogs and other community sites. Sa Figure I.1: Simulation Mechanical Online Help Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 3
Introduction InfoCenter Web Links Search the Help Files using Keywords All of the pages in the Help files can be searched based on keywords. The keywords are entered at the top of the "Search" tab on the left side of the online Help screen. Topics that match the search criteria are listed below. Keywords are used to search the Help files. You may use single or multiple keywords. Boolean operators (AND, OR, NEAR, and NOT) are available to enhance the search utility. Also, phrases may be enclosed in quotes to search only for a specific series of words. At the right end of the Simulation Mechanical title bar is a Help search field. You can search the online Help from within the program by entering keywords or phrases within this field. There is also a collection of icons for reaching other various resources, as follows: Communication Center: To setup and access Autodesk Channels and RSS Feeds. Reach the Autodesk Exchange Apps website. Access the About dialog box, which provides the software version, license information, and trademarks and credits. Within the Start & Learn tab of the ribbon, in the New Features and Learn panels, there are several commands that launch web pages, as detailed below. What's New Launches the What's New section of the Help Start Here Launches the New User Quick Start section of the Help Tutorials Launches the Tutorials section of the Help Videos Goes to the index page of the Essential Skills Videos Help Accesses the title page of the Simulation Mechanical Help In addition, the following commands in the Community tab of the ribbon access webpages as detailed below: Discussion Forum Simulation Mechanical discussion groups IdeaStation A place to share your product improvement ideas directly with developers Simulation Community Find answers, share expertise and connect with peers Autodesk University Discover what is happening at Autodesk University Autodesk Labs where you may obtain free tools and explore developing technologies Figure I.2: "Start & Learn" and "Community" Ribbon Tabs 4 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Introduction New User Quick Start Tutorials This portion of the product Help is designed to quickly familiarize new users with the Simulation Mechanical program background, user interface, workflow, and learning resources. There are five Quick Start Videos and two Quick Start Tutorials. These tutorials provide additional guidance and videos as compared to the main set of meshing, modeling, analysis, and results evaluation tutorials (next paragraph). Click the "Start & Learn: Learn: Start Here" command to reach the New User Quick Start section of the Help. Tutorials are available that demonstrate many of the capabilities of the Autodesk Simulation Mechanical software. Each analysis is presented through step-by-step instructions with illustrations to assist the user. The tutorials are accessed from the "Start & Learn: Learn: Tutorials" command. You can download the tutorial models from our online Data & Downloads site, linkable from the top page of the tutorials. Install the models to a local folder of your choice, such as My Documents\Simulation Mechanical Tutorial Models. We recommend that you store your tutorial models in a location outside of the Program Files branch. The tutorials will appear in your default web browser. Autodesk Knowledge Network The Simulation Mechanical pages on the Autodesk Knowledge Network provide a variety of resources for new and experienced users. Go to the following webpage and explore the Overview, Getting Started, Learn & Explore, Downloads, and Troubleshooting tabs. You can order searches within this website according to those that are Most Helpful or those that are Most Recent. How To articles and links to relevant sections of the product Help are listed within the search hits. Autodesk Simulation TV http://knowledge.autodesk.com/support/simulation-mechanical The Simulation TV website hosts a variety of videos featuring capabilities and workflows for various Autodesk Simulation products (Mechanical, CFD, Moldflow, and more). Access the Simulation TV introduction page from the bottom of the Browse Help box on the Simulation Mechanical Online Help website. This page contains a link to the Simulation TV website. Or, use your web browser to navigate to the following address: http://vp.telvue.com/player?s=autodesk How to Receive Technical Support Technical support is reachable through three contact methods. The means you can use depend upon the level of support that your organization has purchased. For example, customers with Basic support must obtain their technical support from the reseller that sold them the software or through written support requests to Autodesk. Advanced support customers can obtain direct Autodesk telephone support. Other options include Enterprise and Per- Incident support. Consult your sales contact for more information. Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 5
Introduction Updates Three ways to contact Technical Support: Reseller: Obtain phone, fax, and/or e-mail information from your reseller. Autodesk Account portal: Access the Autodesk Account portal at https://accounts.autodesk.com Sign in with your ID or email address and password. Click the Create an Account link if you have not yet set up your account. Click the MANAGEMENT link. Finally, from the Support pull-down menu, choose Browse support & learning or Contact us. Autodesk Product Support Phone: (866) 487-8680 When contacting Technical Support: Have your account CSN number or Express Service ID ready before contacting Technical Support. Know the current version number of your software. Have specific questions ready. Remember, Technical Support personnel cannot perform, comment on, or make judgments regarding the validity of engineering work. The software is updated with new functionality on a continual basis. The following three types of releases are provided: 1. A major version: Indicated by the four-digit year of the software release (based upon the Autodesk fiscal year, not the calendar year) 2. A "subscription" version: Customers with a current maintenance subscription are eligible for additional releases that may be made available between major product version releases. These are designated by the addition of the word "Subscription" after the major version number. 3. A service pack: Incorporates minor improvements to a major or subscription release and is indicated by the letters "SP" and a service pack number after the major or subscription version number. How to Determine the Software Version Click on the down-arrow to the right of the question mark icon at the right end of the program title bar. Depending on the state of the InfoCenter display, this icon might be hidden. If so, click the double-arrows at the right end of the InfoCenter icons to expand the InfoCenter and reveal the hidden icons. Select the "About" command from the drop-down box. The dialog box that appears displays the complete version information (with build number, and date). In addition, the program title bar and the splash screen that appears at each program launch will indicate the major version number of the software. However, as with the start menu group name and program shortcut, it will not indicate the subscription and service pack variants. 6 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Introduction How to Obtain an Update Update notifications are provided via the "Communication Center" within the user interface. The Communication Center icon is located in the InfoCenter, at the right side of the program window title bar. The state of the Communication Center icon changes when new information is available. The Communication Center provides up-to-date product support information, software patches, subscription announcements, articles, and other product information through a connection to the Internet. Users may specify how frequently the Live Update information will be polled hourly, every four hours, daily, weekly, monthly, or never. When a program update notification is received, the user will be given the option of downloading and installing it. Background of FEA What is Finite Element Analysis? Finite element analysis (FEA) is a computerized method for predicting how a real-world object will react to forces, heat, vibration, etc. in terms of whether it will break, wear out or function according to design. It is called "analysis", but in the product design cycle it is used to predict what will happen when the product is used. The finite element method works by breaking a real object down into a large number (1,000s or 100,000s) of elements (imagine little cubes). The behavior of each element, which is regular in shape, is readily predicted by a set of mathematical equations. The computer then adds up all the individual behaviors to predict the behavior of the actual object. The "finite" in finite element analysis comes from the idea that there are a finite number of elements in the model. The structure is discretized and is not based on a continuous solution. In any discrete method, the finer the increments, or elements, the more precise is the solution. Previously, engineers employed integral and differential calculus, which broke objects down into an infinite number of elements. The finite element method is employed to predict the behavior of objects with respect to virtually all physical phenomena: Mechanical stress (stress analysis) Mechanical vibration (dynamics) Heat transfer - conduction, convection, radiation Fluid flow - both liquid and gaseous fluids Electrostatic or MEMS (Micro Electro Mechanical Systems) Basic FEA Concepts Nodes and Elements A node is a coordinate location in space where the degrees of freedom (DOFs) are defined. The DOFs of a node represent the possible movements of this point due to the loading of the structure. The DOFs also represent which forces and moments are transferred from one element to the next. Also, deflection and stress results are usually given at the nodes. Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 7
Introduction An element is a mathematical relation that defines how the DOFs of one node relate to the next. Elements can be lines (beams or trusses), 2-D areas, 3-D areas (plates) or solids (bricks and tetrahedra). The mathematical relation also defines how the deflections create strains and stresses. Degrees of Freedom The degrees of freedom at a node characterize the response and represent the relative possible motion of a node. The type of element being used will characterize which DOFs a node will require. Some analysis types have only one DOF at a node. An example of this is temperature in a thermal analysis. A structural beam element, on the other hand, would have all of the DOFs shown in Figure I.3. "T" represents translational movement and "R" represents rotational movement about the X, Y and Z axis directions, resulting in a maximum of six degrees of freedom. Figure I.3: Degrees of Freedom of a Node Element Connectivity Conventional Bonding Elements can only communicate to one another via common nodes. In the left half of Figure I.4, forces will not be transferred between the elements. Elements must have common nodes to transfer loads from one to the next, such as in the right half of Figure I.4. No Communication Between the Elements Figure I.4: Communication through Common Nodes Element Connectivity "Smart Bonding" With the introduction of "Smart Bonding" it is now possible to connect adjacent parts to each other without having to match the meshes (i.e., common nodes at part boundaries are no longer mandatory). This feature is available for both CAD and hand-built models and is applicable to the following analysis types: Static Stress with Linear Material Models Natural Frequency (Modal) Transient Stress (Direct Integration) Communication Between the Elements 8 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Figure I.5, is a pictorial example of two adjacent parts that may be connected via smart bonding. Smart bonding is disabled by default for both new and legacy models (that is, those created prior to implementation of the smart bonding feature). The option may be changed within the "Contact" tab of the Analysis Parameters dialog box. Note that where nodal coordinates fall within the default or user-specified tolerance of each other, they will be matched in the conventional manner. Other nodes along the bonded surfaces or edges those at a relative distance greater than the tolerance will be connected by means of multipoint constraint equations (MPCs). Also note that the "Use virtual imprinting" option within the "Model" dialog box of the mesh settings options will minimize the likelihood that smart bonding will be needed or will occur for CAD-based assemblies. This option attempts to imprint smaller parts on larger parts where they meet, forcing them to have identical meshes. Types of Elements Figure I.5: Connection via "Smart Bonding" The actual supported and calculated DOFs are dependent upon the type of element being used. A node with translational DOFs can move in the corresponding directions and can transmit/resist the corresponding forces. A node with rotational DOFs can rotate about the corresponding axes and can transmit/resist the corresponding moments. Briefly, the general element types are as follows (more details will be given in later chapters): Line elements: A line connecting 2 nodes (such as beams, trusses, springs, thermal rods, and others). 2-D elements: YZ-planar elements that are triangular or quadrilateral (3 or 4 lines enclosing an area). 3-D plates or shells: Planar or nearly planar elements in 3-D space. Each must be triangular or quadrilateral and they represent a thin part with a specified thickness. Brick (solid) elements: Must be enclosed volumes with 4, 5, or 6 faces (triangular and/or quadrilateral) and with 4, 5, 6 or 8 corner nodes. DOFs for element types: Truss: Translation in X, Y and Z. Beam: Both translation and rotation in X, Y and Z. 2-D: Translation in Y and Z. Plate: Five degrees of freedom out-of-plane rotation is not considered. Brick: Translation in X, Y and Z. Introduction Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 9
Introduction How Does Autodesk Simulation Mechanical Work? The software transforms an engineering model with an infinite number of unknowns into a finite model. This is an idealized mathematical model. The model is defined by nodes, elements, loads and constraints. The user interface can be effectively used for the design, analysis and evaluation phases of a typical design process. The simulation software can be extremely useful during the initial concept and design phase to identify areas that can be improved. The simulation software can also be used to quickly evaluate a concept, saving time and engineering resources. This does not necessarily replace the testing needed to evaluate a final design; however the goal is to minimize the prototype and testing stages of design. The General Flow of an Analysis in Autodesk Simulation Mechanical Create a Mesh Start the simulation program Open your model in the FEA Editor environment Select the analysis type Create your mesh Define the FEA Data Assign the loads and constraints Define the material Define the analysis parameters Run the Simulation Note: You can solve all analysis types using the native (legacy) Simulation Mechanical processors. Click the Run with SimMech command to use the native solvers. In addition, Autodesk Nastran processors are available for some of the analysis types. Click the Run with Nastran command to use the Autodesk Nastran solver. Details regarding the Autodesk Nastran capabilities, and the differences between the SimMech and Nastran solvers, are beyond the scope of this training seminar. Review and Present Results Review the desired result types Save images and animations Create presentations and HTML reports 10 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Introduction Stress and Strain Review Equations Used in the Solution A complex system can be broken into a finite number of regions (elements), each of which follows the equations below: F σ = A σ ε = E δ = F L ε dx 0 AE = δ L Where, σ = stress, F = force, A = area ε = strain, E = modulus of elasticity δ = displacement, L = length When the interaction of each region with its neighbor (through the nodes) is considered, a system of equations is developed: where, Known {f} = [K] {x} Unknown {f} is the vector that represents all of the applied loads. [K] is the assemblage of all of the individual element stiffnesses (AE/L) and {x} is the vector that represents the displacements. Since the applied load vector and element stiffnesses are known from the user input, the equation can be solved using matrix algebra by rearranging the equation as follows for the displacement vector: 1 { x} = [ K ] { f } Strains are computed based on the classical differential equations previously discussed. Stress can then be obtained from the strains using Hooke s Law. These basic equations do not require the use of a computer to solve. However, a computer is needed when complexity is added, such as: 1. Geometric complexity (makes the elasticity equation impossible to solve). 2. Variation in material properties throughout the body. 3. Multiple load cases and complex or combined loading. 4. Dynamics. 5. Large systems (require many equations to solve). Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 11
Introduction In practice, the direct inversion is extremely difficult and sometimes unstable. In FEA, matrices can be 50,000 x 50,000 or larger. As a result, other solution methods for this linear equation have been developed. All of these methods use the basic principles of a mathematical method called Gaussian Elimination. The details of this method will not be discussed here, but may be obtained from any numerical programming text. Since differentiation cannot be performed directly on the computer, approximation techniques are used to determine the strain in the model. Since an approximation technique is used for the strains, the finer the mesh, the better the approximation of the strain. For a linear static analysis, stress has a linear relation to strain. Therefore, the stresses will have the same accuracy as the strains. For more complex analyses, more terms are needed. The equation below is needed to represent a true dynamic analysis: { f} = [ m] { x } + [ c] { x } + [ K] { x} where the additional matrices and vectors are, m = mass, c = damping, x = acceleration (second derivative of displacement versus time) x = velocity (first derivative of displacement versus time) Limits of Static Stress with Linear Material Models Deformations are small Strains and rotations are small Changes in stiffness through the model are small Changes in boundary conditions are small Changes in loading direction with deformations are small Material remains in the linear elastic range Mechanical Event Simulation (MES) Overcomes Limitations MES supports: Large deformations Changing boundary conditions Loads moving as the model moves or deforms Nonlinear material behavior Time-dependent loading Large-scale motion Event visualization capabilities: Viewing results with respect to time using the Results environment Animation tools 12 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
MES simulates: Motion Impact Real-time observation of deformations, stresses and strains Failure due to the following: material yielding, local and structural buckling, permanent deformations - residual stress MES capabilities are included within the Autodesk Simulation Mechanical product. For information and training regarding MES, refer to the Autodesk Simulation Mechanical Part 2 training course. Hand-Calculated Example Refer to Appendix A for an example of displacement and stress results for a simple truss structure. A theoretical solution using fundamental equations is presented. In addition, a hand-calculated solution based on the finite element method is presented and its results compared with those obtained by the FEA software. Heat Transfer Review Equations Used in the Solution Heat transfer, as applied to FEA, is actually a conduction problem. The heat loads are boundary conditions. The primary results are a temperature profile and the heat flux through the body of the structure. Conduction is the flow of heat in the body of the structure. This is what is being solved in an FEA problem. The properties of conduction are controlled by the part definition. Only the thermal conductivity (k) is needed for a steady-state analysis. For a transient analysis, the mass density and specific heat will also be required. The governing equation is: where: k = Thermal conductivity A = Area T = Change in temperature L = Length T q = ka L The two most common loads for a thermal analysis are convection and radiation loads. These loads are applied to a surface. The equation for the heat flow due to convection is: ( T ) = ha T Introduction q s where: h = Convection coefficient A = Area T s = Temperature of the surface T = Ambient temperature Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 13
Introduction The equation for the heat flow due to radiation is: q 4 4 ( F. )( T T ) = εσ A V. b where: ε = Emissivity which describes the surface finish for gray bodies. (If ε = 1.0, it is a true blackbody.) σ = Stefan-Boltzmann constant for radiation A = Area Linear Dynamics Review Equation for Dynamic Analyses V.F. = View factor from the surface to the infinite source T = Ambient temperature (in units of absolute temperature) T b = Temperature of the node (in units of absolute temperature) The basic equation of dynamics is: where: [m] = the mass matrix {a} = the acceleration vector [c] = the damping constant matrix {v} = the velocity vector [k] = the stiffness matrix {x} = the displacement vector [m]{a}+[c]{v}+[k]{x}=0 A natural frequency analysis provides the natural vibration frequencies of a part or assembly based on a linear eigenvalue solution. Because the above equation is solved in this linear solution, only mass and stiffness are taken into account. No damping is used. In addition, loads are ignored. As a result, actual displacement output is meaningless except to define the shape of the natural frequency mode. Note that loads are taken into account for a natural frequency with load stiffening analysis, assuming the loads produce membrane stresses that affect the stiffness of the structure. Constraints have a very significant effect on the solution. When no boundary conditions or insufficient boundary conditions are used, rigid-body movement or modes will be found. Unlike a static solution, this is acceptable in a modal analysis. 14 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Chapter 1 Using Autodesk Simulation Mechanical Chapter Objectives Introduction to the user interface o o o o Commands - Ribbon Keyboard Mouse ViewCube and other view controls Complete an example of using Autodesk Simulation o o o o o o Overview of opening an Autodesk Inventor CAD model and creating a mesh Overview of adding loads and constraints to a model Overview of defining material properties Overview of performing an analysis Overview of reviewing results Overview of generating a report Navigating the User Interface In this section, we will introduce you to the Autodesk Simulation Mechanical user interface. There is also a cloud-computing-based version of the product Autodesk Simulation Mechanical Flex. The capabilities, user interface, and workflows are essentially identical for the two products, except that the solutions could also be performed on the cloud for the Flex product. Another difference, for the Flex product, is the absence of the ability to remotely submit solution tasks to other computers on your network. We will begin with an overview of the major components of the graphical user interface. Then we will discuss the ribbon, keyboard, mouse, ViewCube, and additional view controls. Please note that the behavior of the keyboard, mouse and ViewCube as discussed within this manual are based on the default program settings for a clean installation of the product. Many of the features to be discussed are customizable via tabs and settings within the "Application Options" dialog box, reachable via the "Tools: Application Options" command. Figure 1.1 on the next page, along with the legend that follows it introduces the major components of the user interface. This manual is based on Autodesk Simulation Mechanical 2016. If you use another version of the desktop or Flex product, you might encounter slight differences between your version and the interface described herein. Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 15
Sa m Al ple lc p op ro yi vid ng e d an b d ya re S us C e EN st T ric fo tly r fo rev rb ie id w de o n. nly Chapter 1: Using Autodesk Simulation Mechanical Figure 1.1: Autodesk Simulation Mechanical User Interface Interface Legend: 1. Application Button: Opens the Application Menu. Use this menu to access file open, close, merge, export, and save commands; the recent files list; archive functions; program options; and more. 2. Quick Access Toolbar (QAT): A customizable set of frequently accessed commands. 3. Title Bar: The Windows standard title bar displays the program name. The title bar also displays the model name if the display area is maximized. 4. Infocenter: Search the program help or access community center, Autodesk Exchange Apps, and Help/About information using the commands in the Infocenter toolbar. 5. Ribbon: Located just below the title bar and contains the commands, organized into logical tabs and panels within tabs. Help for individual ribbon tabs can be accessed using the links at the bottom of this page. 6. Browser (Tree View): Lists various program and analysis settings (such as the analysis type and units systems), loads and constraints, parts of the assembly, contact settings, and more. Each of the environments, indicated by the three tabs at the top of the browser, performs a different function and includes different browser contents. 7. Display Area: Where the modeling activity takes place. The title bar of this window displays the environment in use and the model name. Clicking one of the tabs on the browser activates the corresponding display area and vice versa. 8. ViewCube: Used to manipulate the model views. See the Introduction to the ViewCube section in this chapter for more information. 9. Navigation Bar: A collection of tools for navigating and manipulating the model display. See the Additional View Controls section in this chapter for more information. 10. Miniaxis: Shows your viewpoint with respect to the three dimensional working area (that is, the directions of the three global axes). The miniaxis location is customizable. Use the View: Appearance: User Interface: Show Scale Ruler and Application Menu: Options: Graphics commands to control the visibility, location, and size of this item. 11. Scale Ruler: Shows the relative size of the model in the current display units. Use View: Appearance: User Interface: Show Miniaxis and Application Menu: Options: Graphics commands to control the visibility and size of this item. 12. Status Bar: Displays various command prompts and status messages. 13. Output Bar: Displays solid meshing results, analysis log and summary files, and convergence plots. 16 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Chapter 1: Using Autodesk Simulation Mechanical Commands Autodesk Simulation Mechanical provides access to program functions through the ribbon, context menus, quick access toolbar (QAT), and Application Menu. The available commands and menus vary for each program environment (FEA Editor, Results, and Report). The ribbon is positioned at the top and is customizable. You can move the panel positions within the same ribbon tab. The commands are logically grouped into panels and tabs. For example, the Mesh tab includes Mesh, CAD Additions, Structured Mesh, and Refinement panels. Each panel will have a specific set of commands. You can add these commands to the quick access toolbar so that they can be easily accessed while any ribbon tab is displayed. To do this, right-click a command in any panel and select "Add to Quick Access Toolbar," as shown in Figure 1.2. Figure 1.2: Adding a Ribbon Command to the QAT Most of the tabs, panels, and commands will not appear until an existing model is opened or a new model is created. Figure 1.3 shows a typical context menu accessed by right-clicking in the display area after selecting a surface on the model. Context menus can be used to add loads and constraints, among other tasks. Figure 1.3: Context Menu In some cases there are too many commands for all to be displayed on the panel. In these situations you can click on the panel name to expand the panel and gain access to further commands (as shown in Figure 1.4). Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 17
Chapter 1: Using Autodesk Simulation Mechanical Using the Keyboard and Mouse Figure 1.4: Additional Panel Commands The keyboard and mouse will both be used to operate within the user interface. The keyboard will be used to enter the required data for loads, constraints, material properties, and so on. It will also be used to modify the behavior of particular mouse operations. That is, certain keyboard keys, when held down, will change the behavior of the mouse. The software supports a number of different mouse configurations. This document assumes that the default template for a new installation is in effect. However, user settings, or those retained from a prior Autodesk Simulation installation, may cause the behavior to differ from that described herein. To ensure that your mouse actions follow the descriptions in this book, access the "Tools: Application Options: Mouse Options" dialog box and choose the "Autodesk Simulation" template. The left mouse button will be used to select items. How items are selected will depend upon the selection mode chosen in the "Selection: Shape" pull-out menu or ribbon. The type of objects that are selected (such as lines, vertices, surfaces, parts, edges, or elements) will depend upon the selection mode chosen in the "Selection: Select" pull-out menu or ribbon. Holding down the <Ctrl> key, while left-clicking on the object, will toggle the selection state of the clicked object. That is, unselected objects will be added to the selection set and previously selected items will be removed from the selection set. Holding down the <Shift> key while left-clicking will only add clicked objects to the selection set (this will have no effect on already selected items). Finally, holding both <Ctrl> and <Shift> while left-clicking will only remove clicked objects from the selection set (this will have no effect on items that are not already part of the current selection set). Pressing the right mouse button with the cursor hovering over items in the browser will access a context menu with commands relevant to the item under the cursor. When items are currently selected, either within the browser or display area, the right-click context menu will display commands and options that are specifically relevant to the selected items. For example, if a surface is selected, only surface-based commands will appear in the context menu. You may right-click anywhere in the display area when items are selected to access the context menu. However, to access the context menu within the browser area, you must right-click with the cursor positioned on one of the selected headings. 18 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Chapter 1: Using Autodesk Simulation Mechanical If a mouse has a wheel, rolling the wheel will zoom in or out on the model. Holding down the middle mouse button or wheel and dragging the mouse will rotate the model. Pressing the <Ctrl> key, while holding the middle button and dragging the mouse, will pan the model, moving it within the display area. Pressing the <Shift> key while dragging the mouse with the middle button down will zoom in and out, making the model larger as the mouse is moved upward and smaller as it is moved downward. You will likely find the use of the middle mouse button and wheel to be more convenient than choosing a command like "Rotate" or "Pan," clicking and dragging the mouse, and then pressing <Esc> to exit the command. Finally, the X, Y, or Z key on the keyboard may be held down while dragging the mouse with the middle button held down. Doing so will rotate the model, as before, but constraining the rotation to be only about the corresponding X, Y, or Z global axis direction. You may also use the left and right cursor keys on the keyboard while holding down X, Y, or Z to rotate about these axes in fixed increments (15 degrees by default). The rotation increment is customizable via the "Tools: Application Options: Graphics: Miscellaneous" dialog box. Introduction to the ViewCube As is true for the mouse, the software also supports a number of different view configurations. This document assumes that the default view options template and view navigation settings for a new installation are in effect. However, user settings, or settings retained from a prior Autodesk Algor Simulation or Autodesk Simulation installation, may cause the view orientations and behavior to differ from those described throughout this document. To ensure that your view commands follow the descriptions in this book, access the "Tools: Application Options: Views Options" dialog box and choose the "Autodesk Simulation" template. Next, access the "Graphics" tab of the same "Options" dialog box, select "Navigation Tools" from the items listed on the left side of the dialog box, and click on the "ViewCube" button. Click the "Restore Defaults" button followed by "OK" to exit the ViewCube Properties dialog. Finally, click the "Steering Wheel" button. Click the "Restore Defaults" button followed by "OK" to exit the "Steering Wheels Properties" dialog box. Click "OK" to exit the "Options" dialog box. Users of other Autodesk products, such as AutoCAD or Autodesk Inventor will likely already be familiar with the ViewCube and associated additional view controls. The ViewCube will be located in the upper right corner of the display by default but may be relocated. The appearance will change depending upon whether the view is aligned with a global plane and whether the cursor is near the cube or not. The ViewCube, in its various appearances, is shown in Figure 1.5. Figure 1.5: ViewCube Appearance (a) Cursor not near the View Cube (b) Cursor on View Cube (view not aligned to a standard face) (c) Cursor on View Cube (standard face view) Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 19
Chapter 1: Using Autodesk Simulation Mechanical The six standard view names, as labeled on the cube faces, are the Top, Bottom, Front, Back, Left, and Right. These may be selected by clicking near visible face names on the cube, as shown in Figure 1.5 (b) or by clicking the triangular arrows pointing towards the adjacent faces, as shown in Figure 1.5 (c), which shows the cursor pointing to the arrow for the Bottom view. In addition, there are clickable zones at each corner and along each edge of the ViewCube. Clicking on a corner will produce an isometric view in which that particular corner is positioned near the center and towards you. Clicking an edge will produce an oblique view, rotated 45 degrees, Half-way between the views represented by the two adjacent faces. When the cursor is near the ViewCube, a "Home" icon will appear above it and to the left, providing easy access to the home view. This is an isometric view having the corner between the Front, Right, and Top Faces centrally positioned and towards you by default. The home view may be redefined by right-clicking the Home icon and choosing the "Set Current View as Home" command while viewing the model positioned as desired. When one of the six standard views is active and the cursor is near the ViewCube, two curved arrows will appear above and to the right of the cube, as seen in Figure 1.5 (c). These are used to rotate the model to one of the four possible variants of the particular standard view. Each click of an arrow will rotate the model 90 degrees in the selected direction. When the face being viewed is changed via the ViewCube, the model may move to the selected view in the manner that requires the least amount of motion. For example, say we are first looking at the Right view, with the word "Right" positioned upright (that is in the normal reading position). Now, if we click the downward arrow above the cube, the model will rotate 90 degrees to reveal the top face. The Top view will be rotated 90 degrees clockwise from the upright orientation (that is, the word "Top" will read in the vertically downward direction). Activating the "Keep scene upright" option will cause the Front, Back, Left, and Right views to automatically be oriented in the upright position (Top above, Bottom below) when changing to any of these views. You may, however, rotate the view after initial selection, if desired. Go to "Tools: Application Options: Graphics: Navigation Tools: ViewCube" to locate the "Keep scene upright" setting. It is activated by default. The point of this discussion is that whenever a new face is selected using the ViewCube, the resultant view rotation may differ, depending upon the prior position of the model. If the resultant orientation is not what is desired, simply click one of the curved arrows to rotate the view. Additional View Controls The Navigation Bar Immediately below the ViewCube is a Navigation Bar that contains additional view controls. This consists of seven tools, each of which may be individually enabled or disabled. All are on by default. Figure 1.6 shows the Navigation Bar. From top to bottom, the seven tools are as follows: Steering Wheels Pan Zoom Orbit Center Previous View Next View Look At Each of these icons, except for the Previous and Next commands, function as a toggle clicking it once to activate a command and again to deactivate it. Several of the tools (such as Pan, Previous, and Next) are self-explanatory. Figure 1.6: Navigation Bar 20 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Chapter 1: Using Autodesk Simulation Mechanical The "Zoom" tool includes a fly-out menu allowing the choice of one of four different zooming modes Zoom, Zoom (Fit All), Zoom (Selected), and Zoom (Window). The first of these causes the model to become larger as the cursor is moved upward in the display area and smaller when it is moved downward. The Fit (All) mode encloses the extents of the whole model. After selecting objects in the display area, the Zoom (Selected) tool fits the selected items into the display area. Finally, after selecting the Zoom (Window) tool, you click and drag the mouse to draw a window defines the area you wish to expand to fill the display area. The Look At tool includes a fly-out menu allowing the choice of one of three different Look At modes Look At, Look At Surface, and Look At Point. Look At Surface positions the view with the clicked surface parallel to, or tangent to, the screen and zooms in or out to enclose the whole surface within the display area. Look At Point places the surface to which the clicked point belongs parallel to, or tangent to, the screen but encloses the view more tightly, with the clicked point centered in the display area. Look At places the surface to which the clicked point belongs parallel or tangent to the screen but does not modify the current amount of zoom. The viewpoint rotates and/or pans to center the clicked point, but the view is not zoomed in or out. The "Orbit" tool has two variants, selectable via a fly-out menu Orbit, and Orbit (Constrained). The former allows the model to be rotated freely in any direction. The Constrained option causes the model to rotate only about the global Z-axis, similar to pressing the Z key while dragging the mouse with the middle button depressed. The "Center" tool is used to center a point on the model within the display area. Click with the mouse to specify the desired center point after selecting the Center command. This point also becomes the display pivot point, about which the model pivots when being rotated. The "Steering Wheel" tool is customizable and, in its default setting, produces the Full Navigation Wheel shown in Figure 1.7. The full navigation wheel floats above the model view, following the cursor position. It provides an additional access method for several functions found elsewhere on the view tools pallet as well as a few additional functions. Figure 1.7: Full Navigation Wheel The "Rewind" button on the navigation wheel presents a timeline of thumbnails representing various views that have been used during the modeling session. Simply release the mouse button with the cursor positioned at the thumbnail representing the view to which you wish to jump. This is more convenient than pressing the previous or next view buttons multiple times. For additional information concerning these view controls, consult the Navigation Bar topic in the User Interface branch of the online Help. Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 21
Chapter 1: Using Autodesk Simulation Mechanical Legacy View Controls in Autodesk Simulation Mechanical Traditional view controls and options are also provided via the View tab of the command ribbon at the top of the screen. Options for displaying or hiding the mesh or model shading may be found here as well as eight pre-defined, standard view orientations. The orientations will depend upon the currently active Views Options template (previously discussed in the "Introduction to the ViewCube" section of this chapter). There is also a "User-defined Views" dialog box that may be used to save, modify, or restore custom views. Additional capabilities include a local zoom feature and display toggles for the scale ruler, mini axis, and perspective mode. The "Local Zoom" feature displays a small rectangle that represents the area to be magnified. A larger rectangle shows an overlay of the magnified region. You may click on and drag the local zoom window to position it anywhere on the model within the display area. The size of the local zoom area and magnified overlay and also the zoom level can be customized via the "Application Menu: Options: Graphics: Local Zoom" dialog box. For additional information concerning the legacy view controls, consult the online Help. Steel Yoke Example This example is an introduction to static stress analysis with linear material models. The example will give step-by-step instructions to create a mesh and analyze a three-dimensional (3D) model of a steel yoke under an applied force. There are three sections: Setting up the model Open the model in the FEA Editor environment. Specify an absolute mesh size of 0.25" and create the mesh on the model. Add the necessary forces and boundary conditions and define the model parameters. Visually check the model for errors with the Results environment. Analyzing the model Analyze the model using the static stress with linear material models processor. Reviewing the results View the displacements and stresses graphically using the Results environment. Use the Inventor solid model, yoke.ipt, located in the "Chapter 1 Example Model\Input File" folder in the class directory (or extracted to your computer from the solutions archive) to create a simple model of the steel yoke shown in Figure 1.8. The right half of the small hole will be fixed. A force of 800 pounds will be applied to the left half of the large hole and acting towards the left, as shown in the figure. The yoke is made of Steel (ASTM-A36). Analyze the model to determine the displacements and stresses. Figure 1.8: Steel Yoke Model 22 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Chapter 1: Using Autodesk Simulation Mechanical Opening and Meshing the Model The FEA Editor environment is used to create a mesh for all solid models. You can open CAD solid models from any of the CAD solid modelers that Autodesk Simulation Mechanical supports. You can also open models of any of the universal CAD formats that are supported. Here, we are going to open an Autodesk Inventor CAD model. You do not have to have Inventor installed on the simulation computer. "Start: All Programs: Autodesk: Autodesk Simulation 20xx: Autodesk Simulation Mechanical 20xx" "Start & Learn: Launch: Open" "Autodesk Inventor Files (*.ipt, *.iam)" "Yoke.ipt" Open "No", No "Linear: Static Stress with Linear Material Models" "OK" The model will appear in the FEA Editor environment. "Mesh: Mesh: Generate 3D Mesh" "No" If not already started, press the Windows "Start" button and access the "All Programs" pull-out menu. Select the "Autodesk" folder and then the "Autodesk Simulation 20xx" pull-out menu. Choose the "Autodesk Simulation Mechanical 20xx command. If the Open dialog box is not already displayed, click the "Open" command in the Launch panel of the "Start & Learn" tab. Alternatively you can select Open from the quick access toolbar or Application Menu. Select the "Autodesk Inventor Parts (*.ipt, *.iam) option in the "Files of type:" drop-down box. Select the file "Yoke.ipt in the Chapter 1 Example Model\Input File directory. Press the Open button. Two dialog boxes will appear asking if you want to import work points or 3D sketches that might exist in the CAD model. Click the "No" button twice as there are no work points or 3D sketches of interest in this model. A dialog box will appear asking you to choose the analysis type for the model. From the pull-out menu, choose "Linear: Static Stress with Linear Material Models" and press the "OK" button. Select the "Mesh tab. Click the Generate 3D Mesh" command in the "Mesh" panel to produce a mesh using default settings. Click "No" when asked if you would like to view the mesh results. Note that the default mesh is a bit too coarse for this model, particularly in the area of the small hole. Next, we will adjust the mesh size to make it finer and try once more. "Mesh: Mesh: 3D Mesh Settings" Mouse "Mesh Model" "No" Click the 3D Mesh Settings" command in the "Mesh" panel. Move the "Mesh Size" slider to the right (towards Fine) until the tool tip indicates "65%." Click the "Mesh Model" button. Click "No" when asked if you would like to view the mesh results. By default, the model is shaded based on the original CAD surface data. This makes surfaces easier to select and makes highlighting more apparent when selecting them. However, it tends Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 23
Chapter 1: Using Autodesk Simulation Mechanical to obscure mesh lines on concave curved surfaces. We will disable the CAD Surfaces option temporarily to see the full mesh more clearly. "View: Appearance: CAD Surfaces" Mouse Setting up the Model Adding Constraints Select the "View" tab and click the "CAD Surfaces" option in the "Appearance" panel to deactivate it. Click and drag using the middle mouse button to rotate the viewpoint and inspect the mesh all around the part. This mesh appears to be acceptable. When done inspecting it, position the model to see the inside of the small hole, as shown in Figure 1.9. This surface will be constrained. Figure 1.9: Yoke Rotated to Select Constrained Surfaces The FEA Editor environment is also used to specify all of the element and analysis parameters for your model and to apply the loads and constraints. When you initially come into the FEA Editor environment with the yoke model, you will notice a red X on certain headings in the browser. This signifies that this data has not yet been specified. You will need to eliminate all of the red Xs before analyzing the model. After creating the mesh, the "Element Type" heading in the browser is already set to "Brick" and the default "Element Definition" parameters have been accepted. The material information is also imported from Inventor. Constraints describe how a finite element model is tied down in space. If an object is welded down so that it can neither translate nor rotate, the object is fully constrained. "View: Appearance: CAD Surfaces" "Setup: Constraints: General Constraint" Click the "CAD Surfaces" option in the "Appearance" panel again to reactivate it. Select the "Setup" tab. Click on the "General Constraint" command in the "Constraints" panel. The dialog box shown in Figure 1.10 will appear. 24 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Chapter 1: Using Autodesk Simulation Mechanical Mouse "Fixed" "OK" Adding Forces to the Model Figure 1.10: Creating Surface General Constraint Dialog Box Click on the surface on the right side of the small hole as oriented in Figure 1.9. This is the +X half of the hole. Press the "Fixed" button. Note that all 6 of the checkboxes in the "Constrained DOFs" section to the left are activated. This means that the nodes on this surface will be totally constrained. Press the "OK" button to apply these boundary conditions. Now there will be green triangles on the nodes of the surface that was selected. This signifies a fully constrained boundary condition. In this section, you will add the 800 lb force in the X direction to the large hole. Mouse Click near the middle of the ViewCube edge where the Top and Right faces meet, as shown in Figure 1.11. A light blue rectangle indicates the clicking zone. This provides a good viewpoint for seeing and applying a load to the -X half of the large hole. Figure 1.11: Where to Click the ViewCube for the Desired Oblique View "Loads: Force" Mouse Click on the "Force" command in the "Loads" panel. The dialog box shown in Figure 1.12 Click on the surface on the -X side of the large hole. Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 25
Chapter 1: Using Autodesk Simulation Mechanical Figure 1.12: Creating Surface Force Dialog Box -800 Type "-800" in the "Magnitude" field. "X" "OK" Mouse Select the "X" radio button in the "Direction" section. Because the magnitude is negative, the applied force will act in the -X direction. Press the "OK" button to apply the surface force. Now there will be green arrows on the surface that was selected. They point in the -X direction. Click near the center of the Top face of the ViewCube for a Top view of the model. The yoke should now look like Figure 1.13. Figure 1.13: Yoke after Constraint and Load are Applied 26 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Chapter 1: Using Autodesk Simulation Mechanical Assigning the Parameters Once the model has been constructed and the loads and constraints have been applied, use the FEA Editor environment to specify material properties. Mouse Right-click on the "Material" heading for Part 1. "Edit Material " Select the "Edit Material " command. The "Element Material Selection" dialog box will appear. "Steel (ASTM-A36)" Highlight the "Steel (ASTM-A36)" item from the list of available materials as shown in Figure 1.14. "Edit Properties" "OK" "OK" "Yes" Figure 1.14: Element Material Selection Dialog Box Press the "Edit Properties" button to view the material properties associated with this steel. Press the "OK" button to exit the "Element Material Specification" dialog box. Press the "OK" button to accept the information entered in the "Element Material Selection" dialog box for Part 1. Accept the warning to override default material defined within Inventor. Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 27
Chapter 1: Using Autodesk Simulation Mechanical "Analysis: Analysis: Check Model" "Tools: Environments: FEA Editor" "View: Orientation: Isometric View" Analyzing the Model "Analysis: Analysis: Run Simulation" Reviewing the Results Select the "Analysis" tab. Click on the "Check Model" command in the "Analysis" panel. Select the "Tools" tab. Press the "FEA Editor" command in the "Environments" panel. Select the "View" tab. Click on the options button at the bottom of the "Orientation" command in the "Navigate" panel. Select "Isometric View" from the pull-out menu. Select the "Analysis" tab. Click on the "Run Simulation" command in the "Analysis" panel. When completed, the model will be displayed in the Results environment and the Displacement Magnitude will be displayed, as shown in Figure 1.15 below. Note the maximum displacement value. Figure 1.15: Yoke Model as Displayed in the Results Environment "Results Contours: Stress: von Mises" Note the maximum von Mises value. The maximum von Mises stress and maximum deflection should be similar to the values in the table below. Maximum von Mises Stress (psi) Maximum Displacement (in) ~2,292 ~0.0005 28 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015
Chapter 1: Using Autodesk Simulation Mechanical Viewing the Displaced Shape Viewing the displaced shape is always the best way to get an overall understanding of how the model reacted to the applied load. A displaced model alone or a displaced model overlaid with an undisplaced model can be displayed. "Results Contours: Show Displaced: Displaced Options" "Transparent" Mouse Creating an Animation "Results Contours: Captures: Start " "Captures: Stop" Click on the options button next to the "Show Displaced" command in the "Displacement" panel. Then select "Displaced Options" command. Select the "Transparent" radio button in the "Show Undisplaced Model As" section. Click the "X" button in the upper right corner of the Displaced Model Options dialog box to close it. Select the "Results Contours" tab. Click on the "Start" command in the "Captures" panel. Click on the "Stop" command in the "Captures" panel. The preceding steps animated the results within the display area but did not create an animation file that we can place in our report. In the following steps, we will export an animation file that can be included in the report or copied to and played on any computer. "Animate: Save As AVI" "von Mises Stress Animation" "Save" "No" Generating a Report Click on the "Animate" command in the "Captures" panel. Then select "Save As AVI" option. Rather than using the default file name, type "von Mises Stress Animation" into the "File name:" field. Press the "Save" button to save the animation to an AVI file format. Press the "No" button when asked if you want to view the animation. In this section, you will automatically create an HTML report using the Report Configuration Utility. "Tools: Report" "Report: Setup: Configure" Select the "Tools" tab. Click on the "Report" command in the "Environments" panel. Select the "Configure" command in the "Setup" panel. This will open the dialog box shown in Figure 1.16. Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015 29
Chapter 1: Using Autodesk Simulation Mechanical Figure 1.16: Report Configuration Utility NOTE: Clicking on any of the checkboxes will toggle the inclusion state of the item (i.e. whether it is to be included or excluded from the HTML report). When selecting included portions of the report, to modify them. Click on the item name and not on the checkbox. This will select the item without toggling the checkbox state. Mouse Activate the checkbox next to the "Logo" heading. This will include the default Autodesk Simulation Mechanical product name at the top of the report. Note that you may also customize the logo by browsing to and selecting your own image file. Several different image file formats are supported. The logo size and alignment may also be adjusted by right-clicking on it and choosing the "Format Image" command. You may also select the image and then click and drag the handles that appear around the image border while it is selected to resize it. Mouse Mouse: Yoke Design Mouse: Analysis of Yoke under 800 lbf Loading Mouse Select the "Project Name" heading. Click and drag the mouse to select the text, "Design Analysis" and type "Yoke Design" to replace it. Click and drag the mouse to select the text, "Project Title Here" and replace this text by typing "Analysis of Yoke under 800 lbf Loading". Select the "Title and Author" heading. Your Name Your Department Mouse Type your name into the "Author" field. Type your department name into the "Department" field. Select the "Reviewer" heading. 30 Autodesk Simulation Mechanical 2016 Part 1 Seminar Notes 4/09/2015