MSC.Marc and MSC.Marc Mentat. Release Guide Version 2003

Transcription

1 MSC.Marc and MSC.Marc Mentat Release Guide Version 2003

2 Corporate Copyright 2003 MSC.Software Corporation All rights reserved. Printed in U.S.A. Europe MSC.Software Corporation MSC.Software GmbH 2 MacArthur Place Am Moosfeld Santa Ana, CA München, GERMANY Telephone: (714) Telephone: (49) (89) Fax: (714) Fax: (49) (89) Asia Pacific MSC Japan Ltd. Entsuji-Gadelius Building 2-39, Akasaka 5-chome Minato-ku, Tokyo , JAPAN Telephone: (81) (3) Fax: (81) (3) Worldwide Web Part Number: MA*V2003*Z*Z*Z*DC-REL Disclaimer THE CONCEPTS, METHODS, AND EXAMPLES PRESENTED IN THE DOCUMENTATION ARE FOR ILLUSTRATIVE AND EDUCATIONAL PURPOSES ONLY, AND ARE NOT INTENDED TO BE EXHAUSTIVE OR TO APPLY TO ANY PARTICULAR ENGINEERING PROBLEM OR DESIGN. USER ASSUMES ALL RISKS AND LIABILITY FOR RESULTS OBTAINED BY THE USE OF THE COMPUTER PROGRAMS DESCRIBED HEREIN. IN NO EVENT SHALL MSC.SOFTWARE CORPORATION BE LIABLE TO ANYONE FOR ANY SPECIAL, COLLATERAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES ARISING OUT OF, RESULTING FROM, OR IN CONNECTION WITH USE OF THE CONTENTS OR INFORMATION IN THE DOCUMENTATION. MSC.SOFTWARE CORPORATION ASSUMES NO LIABILITY OR RESPONSIBILITY FOR ANY ERRORS THAT MAY APPEAR IN THE DOCUMENTATION. THE DOCUMENTATION IS PROVIDED ON AN AS-IS BASIS AND ALL EXPRESS AND IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE DISCLAIMED, EXCEPT TO THE EXTENT THAT SUCH DISCLAIMERS ARE HELD TO BE LEGALLY INVALID. MSC.SOFTWARE CORPORATION RESERVES THE RIGHT TO MAKE CHANGES IN SPECIFICATIONS AND OTHER INFORMATION CONTAINED IN THE DOCUMENTATION WITHOUT PRIOR NOTICE. Trademarks MSC, Dytran, MARC, and Patran are registered trademarks of MSC.Software Corporation or its subsidiaries in the United States and/or other countries. MSC., MSC.Dytran, MSC.Marc, and MSC.Patran are trademarks of MSC.Software Corporation. NASTRAN is a registered trademark of the National Aeronautics and Space Administration. MSC.Nastran is an enhanced proprietary version developed and maintained by MSC.Software Corporation. All other trademarks are the property of their respective owners. Third Party Software Program Credits METIS is copyrighted by the regents of the University of Minnesota. NT-MPICH is developed by Lehrstuhl für Betriebssysteme der RWTH Aachen. Copyright Lehrstuhl für Betriebssysteme der RWTH Aachen. Government Use Use, duplication, or disclosure by the U.S. Government is subject to restrictions as set forth in FAR (Commercial Computer Software) and DFARS (Commercial Computer Software and Commercial Computer Software Documentation), as applicable.

3 C O N T E N T S MSC.Marc and MSC.Marc Mentat Release Guide Contents List of the New Functionalities, 2 Description of the New Functionalities, 4 Examples of New Functionality, 69 List of Defects Fixed in this Release, 71 List of Known Problems in this Release, 79 Troubleshooting Tips, 84 Web Updates for Bug Fixes, 90 List of Build and Supported Platforms, 91 List of Dropped Platforms, 94 Important Notes, 95 Platform Specific Notes, 98 Security, 102

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5 MSC.Nastran for Windows Release Guide MSC.Marc and MSC. Marc Mentat Release Guide List of the New Functionalities Description of the New Functionalities Examples of New Functionality List of Defects Fixed in this Release List of Known Problems in this Release List of Build and Supported Platforms List of Dropped Platforms Important Notes Platform Specific Notes Security The release of MSC.Marc 2003 family of products broadly encompasses the following objectives: Major new enhancements in several areas in both solver and GUI capabilities Substantial improvements in quality several defects in the previous versions have been fixed Notable increase in robustness of analysis Notable solver speed improvements

6 2 List of the New Functionalities MSC.Marc 2003 I. List of the New Functionalities MSC.Marc 2003 There are significant enhancements in various key technology areas in addition to improvements in existing functionality in the MSC.Marc family of products. The extent of the improvements is fairly substantial and spans a broad range of industries. A list of new features for both the solver and graphical user interface is given below. Details can be found in the following section for the enhancements and modifications in both the MSC.Marc and MSC.Marc Mentat 2003 versions. 1. Analysis Performance Improvements, 4 A. Direct Sparse Solver Improvements, 4 B. Sparse Iterative Solver Improvements, 5 C. Other Enhancements for Memory Reduction, 5 D. Improvements in Parallel Analysis, 5 E. Improvements in Thermal Radiation Calculations, 5 F. Improved Convergence in Heat Transfer Analysis, 5 G. Analysis Procedure Improvements, 6 2. Contact, 7 A. Thermal Contact, 7 B. True Quadratic Contact, 8 C. Beam Contact, 9 D. Contact Improvements, 10 E. Scaling of Rigid Surface, 10 F. Separation Controls, Electrical/Electronics, 11 A. Piezoelectric Analysis, 11 B. Coupled Electrical-Thermal-Mechanical (Joule-Mechanical Analysis), 12 C. Improvements in Electromagnetics, Element Technology, 14 A. New Reduced Integration Thick Shell Element, 14 B. Rebar Element Enhancement, 15 C. Continuum Composite Element Enhancement, 15 D. Beam Element Enhancements, 16 E. Gas Filled Cavities, Material Models, 18 A. Anisotropic Plasticity, 18 B. Shape Memory Alloys, 19 C. Thermo-Mechanical Extensions to Gasket, 21 D. Implicit Creep, 22 E. Chaboche Model for Viscoplasticity, 24

7 List of the New Functionalities MSC.Marc Mentat Automatic Time Stepping Scheme Enhancements, Steady State Rolling of Tires, Multi-point Constraints, 30 A. INSERT Option, 30 B. General Analysis Enhancements Nonlinear Springs, 30 C. MSC.Nastran Rigid Body Elements, Global Remeshing and Adaptive Meshing, 33 A. Automatic Global Remeshing with Tetrahedral Elements, 33 B. Adaptive Meshing, Machining, Miscellaneous, 38 A. Axisymmetric to 3-D Analysis Enhancements, 38 B. Forming Limit Diagram (FLD) and Principal Engineering Strains, 38 C. Large Strain Support for Fracture Mechanics, 40 MSC.Marc Mentat MSC.Marc Mentat Menu Enhancements, MSC.Marc Mentat Preprocessing Enhancements, 44 A. Attach, 44 B. New Combined Mesh/Geometry Commands, 46 C. Modifications to Mesh Generation Commands, 48 D. Modifications to the Automatic Meshers, 51 E. New Automatic Meshers from MSC.Patran, 52 F. Model Parameters, 53 G. Multidimensional Tables, 54 H. New Table Style Input, 57 I. Referencing Tables with Multiple Independent Variables, 58 J. Passing a Table Formula to MSC.Marc; Extrapolation Flag, 59 K. Electromagnetic Boundary Conditions, 60 L. Harmonic Boundary Conditions, 60 M. Nodal Ties, Servo Links, and Springs, 61 N. Enhancement of Domain Decompositiont, 62 O. Job Submission, 63 P. Python, 63 Q. Miscellaneous Changes, MSC.Marc Mentat Postprocessing Enhancements, 66 A. MPEG and AVI Animation, 66 B. Post Procedure File, 67 C. Merge Contact Model Files, 68 D. Generalized XY-Plot, 68

8 4 Description of the New Functionalities Analysis Performance Improvements II. Description of the New Functionalities 1. Analysis Performance Improvements There are a few major areas where the performance has been substantially improved for large problems in MSC.Marc 2003 release: A. Direct Sparse Solver Improvements Storage improvements have been made in the multifrontal sparse solver which should affect all problems. Furthermore, the default optimizer is now Optimize 11 which results in major speed and memory improvements over the previous optimizers. In Core Memory Use Memory Size Optimize 11 Optimize 9 Optimize 10 Figure 1: Comparison of Memory Usage Matrix Solution Wall Time 800 Size Optimize 11 Optimize 9 Optimize Time Figure 2: Comparison of Matrix Solution Time

9 Description of the New Functionalities Analysis Performance Improvements 5 B. Sparse Iterative Solver Improvements The sparse iterative solver using Incomplete Cholesky preconditioner has been rewritten to achieve significant improvements in speed. This has been achieved for single as well as parallel analysis as witnessed in Case 1: Sparse Iterative Solver Enhancements.of the New Features Guide C. Other Enhancements for Memory Reduction There have been two major changes in the treatment of memory for large problems, namely: The first is a general rewrite of the memory management scheme and contact data structure to improve memory allocation in large problems, with or without contact. The second is a contact memory reduction option for cases where only small sliding takes place. In particular for three-dimensional models e.g. automotive engine blocks with large amounts of contact surface data, the memory savings can be significant. Since no significant nonlinear contact behavior is taken into account with this option it does not support friction and coupled behavior. This option can be activated through the CONTACT option or in MSC.Marc Mentat via the button LINEAR CONTACT WITH REDUCED STORAGE in JOBS MECHANCIAL CONTACT CONTROL INITIAL CONTACT menu. D. Improvements in Parallel Analysis METIS based domain decomposer has been implemented in MSC. Marc Mentat to optimally decompose the domains so as to minimize the nodes on the interdomain boundaries. This results in significant reduction of memory and speed for certain problems with complex geometries. E. Improvements in Thermal Radiation Calculations When performing radiation calculations in open or closed cavities, a contribution will be made to the operator matrix based on the information given in the viewfactor file. Depending on the number of faces in the cavity, and the visibility of surfaces, the contribution can substantially increase the bandwidth of the system. A new procedure has been added which uses an implicit/explicit technique based on the magnitude of the viewfactor and a user provided cutoff. For large models (with over 10,000 radiating faces), the improvements can be dramatic. F. Improved Convergence in Heat Transfer Analysis If in a heat transfer analysis the external flux is temperature dependent, (e.g. with a temperature dependent film coefficient), then the problem to be solved is nonlinear. In such cases, the speed of the convergence process can be significantly improved by introducing the derivative of the flux with respect to the temperature in the conductivity matrix and in the right-hand-side vector of the set of equations to be solved. This derivative can be entered in user subroutine forcdt.f (point fluxes), flux.f (distributed edge/face fluxes) and film.f (film coefficient). The procedure can be used in both steady state and transient heat transfer analyses.

10 6 Description of the New Functionalities Analysis Performance Improvements G. Analysis Procedure Improvements A rewrite has been done for parts of the analysis using the multiplicative decomposition of deformation gradient making analysis significantly faster for lower-order elements. This procedure is activated for plasticity (when using PLASTICITY,5 or choosing LARGE STRAIN MULTIPLICATIVE in the JOBS MECHANICAL ANALYSIS OPTIONS menu in MSC.Marc Mentat) or rubber elasticity (when using ELASTICITY,2 or choosing LARGE STRAIN UPDATED LAGRANGE elasticity in the JOBS MECHANICAL ANALYSIS OPTIONS menu in MSC.Marc Mentat).

11 Description of the New Functionalities Contact 7 2. Contact Several new Contact features as well as enhancements and improvements to existing contact functionality have been made in MSC.Marc 2003 release, the most notable are: A. Thermal Contact Different analysis types are now supported with contact: Pure heat transfer analysis. Compared to previous versions, where a coupled thermo-mechanical analysis was always required to perform a heat transfer analysis with contact bodies, this significantly increases the speed and reduces the amount of memory needed if one is only interested in the heat transfer solution. Near Thermal Contact When bodies are close to one another but are not yet touching, heat can be transmitted between the two surfaces through convection and radiation. The convection can be dependant upon the distances between the two surfaces. This capability has been added to the 2003 release. Joule heating (coupled electrical-thermal) analysis and coupled Joule-mechanical (coupled electrical-thermal-mechanical) analysis. The electrical contact, transmission of current is treated analogously to the transmission of heat. In a thermal or coupled thermal-mechanical analysis, heat transfer through small gaps in a model can be taken into account using the near contact option. Temperature (x100) pipe house node on house near contact node on house contact Time (x10000) node on pipe near contact node on pipe contact Figure 3: Thermal Contact Analysis Note: Figure 3 shows a temperature as a function of time for two nodes in Contact, one from the Pipe and one from the House. Results are with the Near Contact Option Switched On/Off.

12 8 Description of the New Functionalities Contact In MSC.Marc Mentat, the CONTACT BODIES and CONTACT TABLES menus have been redesigned to easily enter the mechanical, thermal and electric properties of (pairs of) contact bodies. Figure 4: Thermal Contact Menus B. True Quadratic Contact True quadratic contact is now supported for higher-order elements (Figure 5). When quadratic elements were used in previous versions, the geometry and displacement field in the contact area were linearized, which could introduce an inaccurate geometry description and stress solution. Now the complete quadratic geometry and displacement field can be taken into account for various quadratic elements: 6-node triangular and 8-node quadrilateral elements in 2-D and 10-node tetrahedral and 20-node hexahedral elements in 3-D. It is well known that for quadratic elements a uniform distributed load results in nonuniform equivalent nodal loads. For this reason, the quadratic contact procedure uses a separation procedure which is based on nodal stresses instead of nodal forces. Figure 5: Advanced Contact Control Menu

13 Description of the New Functionalities Contact 9 Activating genuine quadratic contact has three consequences: first, the midside node is now checked for contact with either rigid bodies or the faces of deformable bodies; second, when a node contacts a deformable body composed of higher-order elemetns, the contact will be based upon the true quadratic shape; and third, the normal to the surface will vary along the face. Figure 6: Quadratic Contact Modeling of Engine Manifold C. Beam Contact The new functionality allows beam or truss elements to come in contact with other beam or truss elements (Figure 5). The elements are viewed as straight cylinders with a circular crosssection. The radius of the cross-section, the contact radius, must be provided by the user. Contact is detected if the cylinders touch each other. In that case, a multi-point constraint is automatically imposed that involves the displacements of the beam nodes. The elements can slide with respect to each other (with or without friction). In addition, contact is automatically transferred to neighboring elements if the contacting point slides off the segment. If a beam slides off a beam, it assumes that it slides to the adjacent beam or else separates from the body. For this reason, the touched beam structure should not have branches. Since the normal stress is not available for beam elements, the beam-to-beam contact uses a separation procedure and a friction model based on nodal forces.

14 10 Description of the New Functionalities Contact (a) (b) Figure 7: Beam-to-Beam Contact Examples (a) Model of Pantograph and Overhead Wire (b) Velocity of Overhead Wire at Increment 200 The nodes of beam elements can also come in contact with other continuum and shell elements as well as a rigid body. D. Contact Improvements (1) A major rewrite has been done for solving problems involving multibody contact more accurately and without penetration. Cases where nodes have multiple constraints due to touching more than one contact body or due to a combination of contact and kinematic boundary conditions are treated more accurately. (2) The corner conditions (concave, convex) of 3-D NURBS surfaces (with or without trimming curves) are taken into account. (3) The iterative penetration procedure has been improved to accurately take into account the complete motion of a (potentially) crossed segment. E. Scaling of Rigid Surface Rigid surfaces can be either expanded or contracted during the analysis. This is often useful for modeling inflation or interference fit problems. If no rotation is applied, the scaling can be nonuniform in the x, y, and z-direction. F. Separation Controls The 2003 release expands the choices of the criteria used to control separation. It is now possible to prescribe that the separation is based upon either separation or forces, and to define the threshold value in absolute terms or as a fraction of the critical stress. This allows the separation to be both independent of the element size and associated with a meaningful physical parameter.

15 Description of the New Functionalities Electrical/Electronics Electrical/Electronics A. Piezoelectric Analysis MSC.Marc version 2003 offers the capability to perform a piezoelectric analysis (Figure 8). A material shows a piezoelectric effect if there is a coupling of the mechanical stress and an electric field: the material deforms when an electric field is applied or vice versa, and generates an electric field when it deforms. The piezoelectric analysis in MSC.Marc is fully coupled, which means that nodal displacements and electric potential are simultaneously solved. To this end, new lower-order 2-D and 3-D elements (element types ) have been developed which can be used in static, transient dynamic, harmonic and eigenvalue analysis. The elements can be mixed with existing mechanical elements with linear or nonlinear material behavior. The mechanical material properties for piezoelectric elements can only be linear elastic, but are allowed to be temperature dependent. The electric and coupling material properties are assumed to be constant. Piezoelectric elements can be used in a contact analysis, where, in case of deformable contact between piezoelectric elements, a multipoint constraint equation is set up for both the nodal displacements and the electric potential. The elements also have their equivalent heat transfer elements, so that they can be used in a coupled thermal-piezoelectric analysis. Possible applications for using the piezoelectric effect are in sensors, transducers and smart materials. Figure 8: Piezo-electric Properties Submenu

16 12 Description of the New Functionalities Electrical/Electronics rotor orbital of a point of the stator stator traveling wave (a) (b) Figure 9: (a) Principle of Operation of an Ultrasonic Moter (b) Z-displacement as a Function of the X-displacement for a Node at the Top of the Stator B. Coupled Electrical-Thermal-Mechanical (Joule-Mechanical Analysis) This multi-physics functionality allows the coupling between the electrical, thermal, and mechanical behavior of a structure (Figure 10). Figure 10: Coupled Electrical-Thermal-Mechanical Analysis MSC.Marc handles the coupled electrical-thermal-mechanical analysis using a staggered solution procedure similar to the one used in coupled electrical-thermal (Joule heating) analysis and in coupled thermal-mechanical analysis. Using this approach, the electrical problem is solved first for the nodal voltages. Next, the thermal problem is solved to obtain the nodal temperatures. Finally, the mechanical problem is solved for the nodal displacements. Typical applications include actuators, high voltage switches, MEMS devices (Figure 11), and electronic circuits. The coupling between the electrical and thermal problems is mainly due to the heat generation due to electrical flow (Joule heating). The thermal and mechanical problems are coupled through thermal strain loads and heat generation due to inelastic deformation and friction. Additional coupling may be introduced in case of temperature dependent electrical conductivity and mechanical stiffness. The mechanical problem may involve geometric and material nonlinearities. Contact is another source of nonlinearity. If contact occurs between deformable bodies or deformable and rigid bodies in the mechanical problem, boundary conditions of the electrical and thermal problems are updated to reflect the new contact conditions. Joule heating and coupled electrical-thermal-mechanical capability is available for continuum elements only.

17 Description of the New Functionalities Electrical/Electronics 13 Figure 11: Temperature Distribution in a Micro-Electro-Thermal Actuator Array C. Improvements in Electromagnetics A change in the number of integration points used for the electromagnetic elements has been made in the 2003 release making them consistent with other elements in MSC.Marc. The axisymmetric element and some memory allocation problem have been fixed. The default value of the penalty factor (to apply the Coulomb gauge, see Volume A) has been updated to improve the accuracy of the solution, and the permanent magnet option has been fixed. Post file includes total instead of the incremental potential, as well as external current and charge. MSC.Marc Mentat menus for solution control and convergence testing have been added.

18 14 Description of the New Functionalities Element Technology 4. Element Technology A. New Reduced Integration Thick Shell Element A new one-point quadrature shell has been developed for linear and nonlinear problems, and replaces the previous element type 140. This new element is a four-node, thick-shell element with global displacements and rotations as degrees of freedom. Bilinear interpolation is used for the coordinates, displacements, and rotations. An MITC4 shell geometry with the ANS (Assumed Natural Strain) method in conjunction with a physical stabilization scheme to construct an element which is free of any spurious modes. The nodal fiber coordinate system at each node is updated with a step procedure in order to consider the warping of the element. A rigid-body projection matrix is applied to extract the rigid-body motion when the element is warped. This element has very good accuracy, reduced memory requirements, and is computationally efficient. Figure 12: Torsion of a Plate Figure 13: Impact of a Ball

19 Description of the New Functionalities Element Technology 15 Compared to standard full integration shell elements, this element is computationally efficient in terms of memory and, therefore, very attractive for nonlinear analysis. The element shows excellent performance for large bending and warping (Figure 12) and highly nonlinear analysis including contact (Figure 13). B. Rebar Element Enhancement A group of isoparametric rebar membrane elements (types 165 to 170) have been developed. These elements can be embedded into 2-D and 3-D solid elements with the newly developed INSERT option to represent the reinforcing cords or rods in composites. The meshes for solid elements and for the rebar membrane elements can be different. The INSERT option is used to enforce the compatibility between the two meshes. This technique allows much more flexibility in defining rebar properties and orientations (Figure 14), and in pre- and postprocessing. In the current release both user subroutine rebar.f and REBAR model definition option can be used to define rebar properties simultaneously. The nonzero values defined by rebar.f have precedence over the REBAR option. Figure 14: Rebar Element Submenu C. Continuum Composite Element Enhancement Enhancements to the current suite of mechanical continuum composite elements ( ) include the following: Only five layers could be used for the solid composite elements in previous version. This has been increased significantly. Now, the maximum number of layers is 510 for the 3-D elements (element types 149, 150) and 1020 for the 2-D elements (element types ). Equivalent thermal continuum elements (element types ) are introduced in this release. These elements can be used for thermal analysis, heat transfer part of thermomechanical coupled analysis, joule heating analysis and electrostatic analysis. The twodimensional elements (element types ) can also be used for magnetostatic

20 16 Description of the New Functionalities Element Technology analysis. All heat transfer capabilities except: latent heat, thermal contact (via the CONRAD GAP model definition option), and fluid channel (via the CHANNEL model definition option) are currently supported for the elements. The maximum number of layers is 510 in 3-D and 1020 in 2-D. D. Beam Element Enhancements Beam elements 14, 52, 76 to 79, and 98 have been modified to incorporate large rotations. The enhancements also allow the torsional mode to be modeled correctly. The kinematics is now based upon the mid-increment rotations and mid-increment strains, however, the residual force calculation and the coordinates update is done at the end of the increment. This enhancement also allows the beams to model mechanisms. E. Gas Filled Cavities This feature allows the modeling of gas filled cavities by automatically updating the volumedependent cavity pressure as the cavity volume change. Examples of applications for this feature include the modeling of airsprings (Figure 15), tires, lungs, athletic shoes containing air bladders, and any pressure vessel undergoing large deformation. Figure 15: Airspring Internal Pressure with and without the Cavity Feature An advantageous aspect of this feature is that the cavity pressure can be directly applied to the structural elements forming the cavity boundary. Thus, if the cavity is completely surrounded by structural elements, no additional elements are required to model the cavity boundary. In regions where the cavity is not enclosed by standard finite elements (e.g. along rigid boundaries), cavity surface elements (elements ) can be used. These elements can also be glued to moving rigid surfaces. They are for volume calculation purposes only and do not contribute to the stiffness equations of the model. By default, MSC.Marc treats the fluid inside the cavity as an ideal gas. The following loading scenarios are available: (1) Closed cavity: The cavity is assumed to contain a fixed amount of gas and no additional load is applied.

21 Description of the New Functionalities Element Technology 17 (2) Applied pressure: A specified pressure is applied to the cavity. (3) Applied mass: A specified amount of mass is added to or subtracted from the gas inside the cavity. The user subroutine, ucav.f allows the user to define and control the cavity pressure for nonideal gas filled cavities and for loading scenarios other than the ones specified above. One can obtain the time history of the cavity volumes and pressures using MSC.Marc Mentat. Figure 16: CAVITIES Menu

22 18 Description of the New Functionalities Material Models 5. Material Models A. Anisotropic Plasticity A new yield function based on Barlat s model, a general criterion for planar anisotropy and particularly suitable for aluminum alloy sheets, has been implemented in MSC.Marc. This criterion has been shown to be consistent with polycrystal-based yield surfaces which often exhibit small radii of curvature near uniaxial and balanced biaxial tension stress states (Figure 17). When compared to the experiments, the Barlat s model is known to predict the earing phenomenon (Figure 18) more accurately. For user-friendliness, MSC.Marc Mentat allows either the direct specification of the Barlat coefficients or can extract these coefficients from experimental data (Figure 19). Figure 17: Comparison of Yield Surfaces for AL 2008-T4 Alloy Barlat Model Figure 18: Earing Shapes and Contact Contours Experiment

23 Description of the New Functionalities Material Models 19 Multistage return mapping method based on Euler backward method is used for isotropic and anisotropic (both Barlat and Hill) plasticity and is activated by use of PLASTICITY, 4 parameter. Regardless of which PLASTICITY parameter is used to describe the Updated Lagrange procedure, this scheme is always used for the anisotropic plasticity. The combined isotropickinematic hardening options can be used for two anisotropic yield functions. Figure 19: Automatic Calculation for Barlat s Anisotropic Coefficients B. Shape Memory Alloys To simulate the behavior of materials exhibiting shape memory characteristics, two models have been implemented in MSC.Marc: Thermo-mechanical Shape Memory Model Mechanical Shape Memory Model Typical uses of such materials are in biomedical devices (stents), airplane-pipe coupling, electrical connectors, thermal actuators, electrical micro-actuators, micropumps in medical applications, and eyeglass frames. Thermo-mechanical Shape Memory Model A phenomenological thermo-mechanical constitutive model designed to describe the deformation processes that occur as a result of either pseudo-elastic or shape memory responses of shape memory alloys (e.g. NiTi) has been implemented (Figure 20). The shape memory and directly related phenomena such as pseudo-elastic response, are caused by the inelastic deformations due to nearly reversible phase transformations that, in turn, are associated with deviatoric transformation strains.

24 20 Description of the New Functionalities Material Models Figure 20: Shape Memory Material Menus: (a) Thermo-mechanical Shape Memory Model (b) Mechanical Shape Memory Model The dilatational components of the transformation strains in such alloys are typically small which allow such transformations to occur with little energy dissipation and to thus be capable of near reversibility. The present model describes the development of transformation induced inelastic strains by the austenite to martensite transformation and by additional texturing of martensite. Upon heating, or unloading these materials, the reverse transformation back to austenite occurs, which are at different temperature and stress levels than that of the forward transformation from austenite to martensite. The shape memory material model is based on decomposing the total strains in term of four contributions: elastic, conventional plastic, thermal strains and strains due to phase transformations. The strains due to phase transformations are in themselves decomposed into two contributions: the TRIP strains (those produced from direct transformation of austenite to martensite, or vice versa) and twinning strains. Mechanical Shape Memory Model The second model can only simulate the pseudoelasticity effect but not true shape memory effect. Since the model is extremely simple and minimum number of input parameters is required, it is easy to use the model for the simulation in the early design stage. Figure 21 shows the comparison of martensite fraction between thermo-mechanical and mechanical shape memory models

25 Description of the New Functionalities Material Models 21 (a) (b) Figure 21: Martensite Fraction: (a) Stent Model (b) Thermo-mechanical Shape Memory Model (c) Mechanical Shape Memory Model C. Thermo-Mechanical Extensions to Gasket The gasket option which involved the use of a gasket material model with lower order continuum composite elements with one layer was introduced in MSC.Marc This option only provided for mechanical behavior with temperature independent through-thickness properties. Also, the temperature loading could only be specified using the NODAL TEMPERATURE or CHANGE STATE options. In many cases, gaskets have thermally dependent properties and are used in situations where the thermal history is unknown. The extensions to the gasket elements in MSC.Marc 2003 provide the following: Gaskets can now be used in mechanical, thermal or thermo-mechanically coupled analysis. For the heat transfer part, the elements used to model the gaskets are type 175 (threedimensional first-order solid element), type 177 (two-dimensional first-order planar element), or type 178 (two-dimensional first-order axisymmetric element). (c)

26 22 Description of the New Functionalities Material Models Through-thickness gasket properties like initial yield pressure, tensile modulus, transverse shear modulus can be specified as a function of temperature and/or spatial coordinates. If necessary, the initial gasket gap can be varied as a function of spatial coordinates. In addition to the mandatory gasket closure distance variable, the loading and unloading paths can also be varied with temperature and/or spatial coordinates. Multi-variate tables can be used to specify these relationships. (a) Figure 22: (a) Pressure Cooker with a Gasket Separating the Lower Part and Cover (b) Temperature Histories at Different Locations in the Gasket Elements Temperature histories at different locations in the gasket part of the pressure cooker are shown in Figures 22 (b). D. Implicit Creep A number of enhancements have been made to the implicit creep capability in MSC.Marc 2003: A fully implicit treatment for power law creep in conjunction with plasticity is now available. The yield stress for the plastic component can be varied as a function of the equivalent plastic strain and temperature. Similarly, the back stress for the creep component can be varied as a function of the equivalent creep strain and temperature. The coefficients for the implicit power law creep expression can be input directly through the CREEP model definition option or specified through user subroutine ucrplw.f. The implicit creep behavior can now be combined with other material behaviors like elastomeric, orthotropic, time-independent elastic-plastic, etc. in the same analysis. It should be noted that the implicit creep capability is currently available for isotropic materials with a von Mises potential. (b)

27 Description of the New Functionalities Material Models 23 The new MSC.Marc Mentat menu for Implicit Creep (Figure 23) is shown below. Figure 23: Creep Properties Menu A CBGA (ceramic ball grid array) mounted onto a PCB (printed circuit board) is cooled down to room temperature from its cure temperature. Figure 24 shows the equivalent creep strain and plastic strain that develop during this process. Creep Strain Figure 24: Equivalent Strains of a CBGA Mounted onto a PCB Plastic Strain

28 24 Description of the New Functionalities Material Models E. Chaboche Model for Viscoplasticity Some materials in engineering application may be subjected to cyclic loadings with a stress amplitude greater than the yield stress. To simulate the cyclic plasticity of such materials, a well known Chaboche viscoplasticity model has been implemented in MSC.Marc (Figure 25). The viscous model (strain rate dependency) is based on the unified viscoplastic formulation. Figure 25: Menu for Chaboche Plasticity Model Features The model combines the isotropic hardening rule to describe the cyclic hardening (Figure 26d) or softening, and the nonlinear kinematic hardening to capture the proper characteristic of cyclic plasticity like Bauschinger (Figure 26a), ratcheting (Figure 26b) and mean stress relaxation effect (Figure 26c). Moreover, the influence of the plastic strain range on the stabilized cyclic response is taken into account by introducing the plastic-strain-range memorization variable (Figure 26e).

29 Description of the New Functionalities Material Models 25 σ σ σ ε ε ε (a) Bauschinger effect (b) Ratcheting (c) Mean stress relaxation σ σ ε ε ε ε (d) Cyclic hardening (e) Cyclic hardening under multiple cyclic loading Figure 26: Characteristic Behavior of Chaboche Plasticity Model

30 26 Description of the New Functionalities Automatic Time Stepping Scheme Enhancements 6. Automatic Time Stepping Scheme Enhancements A number of enhancements has been made to the AUTO STEP algorithm. These enhancements have been made with a two-fold objective: (a) improved user-friendliness of the time stepping scheme; (b) migration of capabilities of other time-stepping schemes to AUTO STEP so as to provide a unified, robust time-stepping scheme for almost all situations. The enhancements made to improve user-friendliness are as follows: Time Step Cutback Prior to MSC.Marc 2003, the time step would only be cut in an arithmetic progression, and for highly nonlinear problems, the number of cutbacks needed would be very large and difficult to estimate apriori. In the MSC.Marc 2003 release, the number of cutbacks needed to satisfy convergence is now automatically determined by the program. If the solution does not converge within a desired number of recycles, the time step for successive cutbacks is decreased in a geometric progression such that within a program-determined number of cutbacks, the minimum time step is reached. User Defined Criterion Prior to MSC.Marc 2003, the user could add appropriate physical criteria based on displacements, stresses, strains, etc. Limits for the physical criteria were not always easy to determine. In the MSC.Marc 2003 release, an input flag has been provided to allow the program to automatically add suitable physical criteria in the analysis. Suitable physical criteria based on strains, plastic strains, creep strains, etc. are automatically added based on a flag set by the user. The choice to bypass these automatic or manually added physical criteria if they are not satisfied is also provided. Stabilization with Quasi-static Damping A quasi-static damping option was introduced with AUTO STEP prior to MSC.Marc 2003 to allow stabilization of non-convergent solutions. This option required the specification of an artificial mass density which was not always easy to determine. This requirement is removed in the current release and the appropriate damping factor needed for static stabilization is automatically determined. Time Step Control by the User Direct control of the time step is possible through use of user subroutine utimestep.f. The enhancements made to AUTO STEP for a unified load-stepping scheme are as follows: Equivalence to AUTO CREEP Scheme AUTO STEP can be used for creep analysis, (in lieu of AUTO CREEP). If an appropriate input flag is set, two physical criteria are automatically added by the program at run-time for explicit creep problems: creep strain increment/elastic strain = 0.5, and stress increment/stress at beginning of increment = 0.5. Equivalence to TRANSIENT Scheme AUTO STEP can be used for thermal analysis or thermo-mechanically coupled analysis (in lieu of TRANSIENT). All temperature tolerances that are specified by the TRANSIENT option can now be specified by AUTO STEP, with the additional advantages that physical criteria

31 Description of the New Functionalities Automatic Time Stepping Scheme Enhancements 27 can be optionally specified with AUTO STEP, and, in coupled problems, AUTO STEP controls the time step based on both thermal and mechanical passes of the run. Equivalence to AUTO THERM or AUTO THERM CREEP Scheme AUTO STEP can be used for thermally driven mechanical problems (in lieu of AUTO THERM and AUTO THERM CREEP). The thermal loads derived from a thermal analysis are applied using the CHANGE STATE option in a mechanical analysis. Allowable state variable increments can be optionally prescribed using AUTO STEP either through a user-defined criterion or program determined automatic physical criterion. Equivalence to AUTO TIME Scheme AUTO STEP can be used for mechanical dynamic problems (in lieu of TRANSIENT or AUTO TIME). This also has the advantage that unacceptable time integration errors due to large time steps with the Newmark-Beta or Single-Step Houbolt operators are avoided through optional additional checks in the AUTO STEP scheme. The new menus showing additional options for the AUTO STEP scheme are shown below. Figure 27: Auto Step Menus A creep problem solved using automated physical criteria with the auto step scheme is compared to the corresponding solution obtained with the auto creep scheme below. Figure 28: Examples of Creep Models

32 28 Description of the New Functionalities Steady State Rolling of Tires 7. Steady State Rolling of Tires One of the major enhancements of tire modeling in MSC.Marc is the steady state rolling (Figure 29). This presents a better solution to the unnecessary computational burden of arriving at a steady state condition through a transient analysis. The second advantage of a rolling contact model is that a finer mesh needs to be used only in the footprint region as opposed to the whole tire. The feature is characterized by Eularian formulation accounting for the inertia effects in spinning/cornering deformable bodies. With an appropriate choice of reference frame, the analysis becomes purely space dependent. This is in contrast to the Lagrangian formulation where the mesh moves in space, thus incurring a tremendous computational expense. Figure 29: Steady State Rolling Submenu Some of the salient features of this functionality are: 1. Inertia effects (centrifugal force and Coriolis force) for spinning/cornering deformation bodies have been taken into account for 3-D lower/higher-order elements (types 7, 84, 117, 120, 9, 18, 21, 35, 57, and 61), as well as 3-D membrane elements (types 9 and 18). 2. The feature can be used with an adaptive time stepping with cutback for various loadcases (AUTO LOAD or AUTO STEP). A specific option of gradual friction increase within a loadcase to enhance the performance for the transition periods from standstill to rolling and from brake to traction is available (Figure 30). 3. In addition to the input in terms of the ground velocity and the tire spinning velocity, a physically more meaningful input for engineers in tire industry, in terms of the ground velocity and the tire axle torque, is available. 4. Rolling contact model currently works only for lower-order 3-D elements with nodal friction. 5. The feature is currently restricted to 3-D analysis.

33 Description of the New Functionalities Steady State Rolling of Tires Friction is only available for lower-order elements. 7. Steady state rolling can incorporate rebar element (types 23, 146, 147, and 148). (a) Figure 30: (a) Tire at Steady State Rolling (b) Rolling Resistance at Different Spinning Velocities (b)

34 30 Description of the New Functionalities Multi-point Constraints 8. Multi-point Constraints A. INSERT Option An INSERT option is developed to insert a list of elements or nodes into a host body, defined by a list of elements. The degrees of freedom of the nodes in the inserted body are automatically tied to the corresponding degrees of freedom of the nodes in the host body, based on their isoparametric locations. This option can be used to place reinforcing cords or rods, such as 2-D rebar membrane elements or truss elements, into solid elements. MSC.Marc Mentat can be used to generate rebar membrane meshes compatible to the host body meshes. Possible applications of the INSERT option also include linking two meshes with different degrees of refinement and applying point loads at some specific locations other than element nodes, among others. Figure 31: INSERT Menu B. General Analysis Enhancements Nonlinear Springs A number of enhancements have been made for springs. Linear and nonlinear springs are now available for mechanical, thermal, and electrical analysis. Nonlinear springs can be specified using one of two methods: (1) The spring stiffness (heat transfer coefficient for thermal springs, electrical conductivity for electrical springs) can be specified as a function of up to four independent variables using multi-variate tables. The typical independent variables that can be used are time, normalized time, increment number, displacement (velocity for dashpots, temperature for thermal springs, voltage for electrical spring). In coupled analysis, the spring stiffness can also be made a function of the average link temperature. (2) The spring force (flux for thermal springs, current for electrical springs) can be specified as a function of up to four independent variables using multi-variate tables. When this option is used, the use of a table as a function of displacement (velocity for

35 Description of the New Functionalities Multi-point Constraints 31 dashpots, temperature for thermal springs, voltage for electrical springs) is mandatory so that the spring stiffness based on the table gradient can be internally calculated. Other variables can include time, normalized time, increment number. Figure 32: Springs Menu Numerical stabilizer flag allows the spring to simply act as a numerical stabilizer without any associated spring forces. Spring ID written out in input deck and in post file. This allows convenient processing for DDM and in user subroutine usprng.f. A sheet-forming problem with nonlinear springs used as drawbeads is shown in Figure 33(a). The nonlinear drawbead force with displacement for a typical spring is shown in Figure 33(b). (a) Figure 33: (a) Sheet-forming with Nonlinear Springs (b) Nonlinear Drawbead Force with Displacement (b)

36 32 Description of the New Functionalities Multi-point Constraints C. MSC.Nastran Rigid Body Elements In order to enlarge the compatibility with MSC.Nastran, MSC.Marc version 2003 supports the widely used MSC.Nastran rigid body elements RBE2 and RBE3. They can be used to easily generate rigid connections in a structure or to distribute applied loads on a finite element model and offer additional flexibility compared to the existing tying types in MSC.Marc. Figure 34: RBE2 and RBE3 Menus

37 Description of the New Functionalities Global Remeshing and Adaptive Meshing Global Remeshing and Adaptive Meshing A. Automatic Global Remeshing with Tetrahedral Elements A new three-dimensional automatic global remeshing capability is added in this release for lower-order tetrahedral element (Figure 35). The feature can be activated using REZONING,2 parameter together with ADAPT GLOBAL option. MSC.Marc uses the meshing technology in MSC.Patran GS-mesher to create meshes with tetrahedral elements. MOM (Mesh On Mesh) surface mesher and tetrahedral mesher are called separately within MSC.Marc solver to produce the new mesh. MOM mesher uses marching algorithm based on the input triangle mesh. This algorithm is proved to be robust, fast and produces high quality surface meshes. The tetrahedral mesher based on Delaunay triangulation technology is activated after the surface meshing is complete. Only element type 157 (and type 135 for thermal mechanical coupling) is supported. Figure 35: Select MSC.Patran Tetrahedral Mesher The remeshing criteria allow users to specify new element size, control remeshing steps, and convert element type from hexahedral element type 7 to element 157, using IMMEDIATE function and CHANGE ELEMENT TYPE (see Figure 37). Figure 36: 3-D Tet Remeshing Model

38 34 Description of the New Functionalities Global Remeshing and Adaptive Meshing Figure 37: Remeshing Control Parameters The remeshing/rezoning with tetrahedral elements can be used in rigid-to-deformable (Figure 38) or deformable-to-deformable contact but not for problems involving self-contact or with small geometry features. Figure 38: Turbine Blade Forging B. Adaptive Meshing 1. Local Adaptivity: Support for Parallel Processing

39 Description of the New Functionalities Global Remeshing and Adaptive Meshing 35 The local adaptive feature is now supported in a parallel analysis. An important limitation in this release is that elements that lie along the boundaries between domains for domain decomposition are not allowed to be subdivided. Thus, care must be taken in the domain decomposition so no boundaries occur where elements will be subdivided. The new nodes and elements that are created due to subdivided elements will be in the same domain as the original elements. 2. Local Adaptivity: New User Subroutines For local adaptivity there are two new user subroutines available: uadap2.f allows elements to be unsubdivided. It is called for all active elements, and if all elements that belong to the same parent element are marked for unsubdivide, the parent element is restored. uadapbox.f allows the box for the "node within box" criterion to be moved.

40 36 Description of the New Functionalities Machining 10. Machining Simulation capability to predict the effects of material removal during manufacturing processes has been added in MSC.Marc This 3-D bulk machining capability is based on the assumption that effects introduced by the cutting process are local and small compared to those due to insitu residual stresses. The salient features of the machining capability are as follows: Seamless integration with CAD files is provided in order to automatically determine the cutter tool shape, cutter motion and other cutter characteristics. The Numerical Control (NC) files that are currently supported include APT and CL files written out from CATIA and APT compilers. The elements falling within a composite volume carved out by the moving cutter are automatically deactivated. Multiple cutting operations like part flip-overs can be simulated through set-up of appropriate loadcases, each accessing a separate NC file. Appropriate preprocessing menus in both MSC.Marc Mentat and MSC.Patran have been added to provide support for the automated element deactivation feature. The user input is primarily the name of the NC file to be used for each loadcase. The menus in MSC.Marc Mentat and MSC.Patran are shown below: The deactivated elements are automatically removed from the post files, so that the cutting operation can be visualized. The limitations of the capability are as follows: Elements that are partially intersected by the composite volume are also deactivated if their centroid falls within the volume. This limitation is currently being addressed, where local refinement of the cut elements will be undertaken to improve the fidelity of the cut area.

41 Description of the New Functionalities Machining 37 The deformation of a block with insitu residual stresses after a 2-part machining operation is shown below. Four loadcases have been used in this problem to simulate the first machining operation, the part flip-over, the second machining operation and the final release from the fixture.

42 38 Description of the New Functionalities Miscellaneous 11. Miscellaneous A. Axisymmetric to 3-D Analysis Enhancements The 3-D part of the analysis using AXITO3D option has been parallelized. This can further achieve tremendous savings in computational times. B. Forming Limit Diagram (FLD) and Principal Engineering Strains The principal engineering strains can now be calculated based on the true strain values for continuum or shell elements. Correspondingly, the Forming Limit Parameter can be obtained for shell/membranes according to the data of Forming Limit Diagram (FLD) provided by users. In addition, if shell/membrane elements are used, the Forming Limit Parameters (FLP) can also be selected. The FLP is defined as the ratio of the major principal engineering strain to the maximum allowable major principal engineering strain given by the Forming Limit Diagram. Major Principal Engineering Strain e 1 FLP > 1 FLD Curve FLP < 1 FLP = 1 0 Minor Principal Engineering Strain e 2 Figure 39: The Definition of Forming Limit Parameter (FLP) Preprocessing The methods employed in MSC.Marc to define the Forming Limit Diagram are: Experimental Data and Predicted FLD Curve. 1. Experimental Data: There are two input format for the experimental data regarding the FLD of materials: a) Fitted function and b) piecewise linear curve or TABLE definition. The details of the above methods are described as below: a. Fitted function: By this method, the polynomial functions are utilized to fit the FLD curve. The functions are shown in MSC.Marc Volume A: Theory and User Information manual.

43 Description of the New Functionalities Miscellaneous 39 b. TABLE definition: The TABLE function in MSC.Marc allows users to define any curves through TABLE model definition option. For example, if user has FLD points of the material, it is possible to define the FLD as piecewise linear curve. See details in MSC.Marc Volume C: Program Input manual. 2. Predicted FLD curve: The predicted FLD curves are generated based on the theories about local and diffuse necking. Both theories assume that the material obeys the power-law strain hardening, σ = Kε n. Figure 40: User Interface for Forming Limit (FLD) Data Input Postprocessing There are three new post data available for postprocessing of FLD related information (Figure 41): Forming Limit Parameter (FLP) Major Engineering Strain Minor Engineering Strain All these data are element based. Users can choose the data type they want to display. For shell/membrane elements, all three data types are available. For continuum elements, only major and minor engineering strains are available.

44 40 Description of the New Functionalities Miscellaneous (a) (b) (c) Figure 41: The distributions of (a) Major Engineering Strains, (b) Minor Engineering Strains and (c) Forming Limit Parameter C. Large Strain Support for Fracture Mechanics The J-integral (Lorenzi option) now supports large strains, both in the total and the updated Lagrange formulation. This makes it possible to calculate the J-integral for rubber applications.

45 Description of the New Functionalities MSC.Marc Mentat Menu Enhancements 41 II. Descri ption of the New Function alities 12. MSC.Marc Mentat Menu Enhancements 1. The ATTACH menus have been changed completely in this version of MSC.Marc Mentat. A brief description of the new ATTACH functionality is located in the MSC.Marc Mentat Preprocessing Enhancements section under Attach, and an example of its use can be found in the MSC.Marc New Features Guide. 2. New menus have been added to support the PATRAN TET MESHER under MESH GENERATION AUTOMESH SOLID MESHING. 3. The menus for HEXMESH EDGE SENSITIVITY, GAP, SHAKES, and RUNS under MESH GENERATION AUTOMESH SOLID MESHING have been moved under ADVANCED CONTROL PARAMETERS. 4. New menus have been added to support the 2D REBAR MESHING under MESH GENERATION AUTOMESH 2D REBAR MESHING. 5. The DUPLICATE menu under MESH GENERATION has been enhanced so that you can duplicate and group of the following: NODES ELEMENTS POINTS CURVES SURFACES SOLIDS TIES SERVOS SPRINGS In addition, any of the items in the above list may be excluded in the items to be duplicated. The values for CENTRIOD, SCALE FACTORS, ROTATION ANGLES, TRANSLATE, and REPETITIONS are text boxes where the values may be edited conveniently. 6. The EXPAND menu under MESH GENERATION has been enhanced so that you can expand any combination of NODES, ELEMENTS, POINTS, or CURVES. The values for CENTRIOD, SCALE FACTORS, ROTATION ANGLES, TRANSLATE, and REPETITIONS are text boxes where the values may be edited conveniently. 7. The MOVE menu under MESH GENERATION has been enhanced so that you can move: NODES ELEMENTS POINTS CURVES SURFACES SOLIDS TIES SERVOS SPRINGS In addition, any of the items in the above list may be excluded in the items to be moved. The values for CENTRIOD, SCALE FACTORS, ROTATION ANGLES, TRANSLATE, and FORMULAS are text boxes where the values may be edited conveniently. 8. The SYMMETRY menu under MESH GENERATION has been enhanced so that you can use any combination of: NODES ELEMENTS POINTS CURVES SURFACES SOLIDS TIES SERVOS SPRINGS

46 42 Description of the New Functionalities MSC.Marc Mentat Menu Enhancements In addition, any of the items in the above list may be excluded in the items to be used in the symmetry operation. The values for CENTRIOD, SCALE FACTORS, ROTATION ANGLES, TRANSLATE, and FORMULAS are text boxes where the values may be edited conveniently. 9. The LINKS menu has been revised to provide MSC.Nastran RBE2 and RBE3 support, a new INSERT links to help in creating rebar meshes. Also, there is no limit on the number of springs or servo links that may be created. For SPRINGS/DASHPOTS, they may now contain properties for MECHANICAL (both STATIC and DYNAMIC), THERMAL or ELECTRICAL and may have tables associated with them. You can also now easily remove all ties or springs. 10. Setting the properties for LAYERED MATERIALS in MATERIAL PROPERTIES have been moved to a submenu under that name. 11. A new menu was added under MESH ADAPTIVITY GLOBAL REMESHING named PATRAN TETRA which provides access to the new MSC.Patran Tetrahedral mesher. 12. The LOADCASES menu was updated and rearranged. New loadcases include JOULE- MECHANICAL and PIEZO-ELECTRIC loadcases. 13. The JOBS menu was updated with new jobs that include JOULE-MECHANICAL and PIEZO-ELECTRIC. 14. A new menu for STEADY STATE ROLLING PARAMETERS was added under JOBS MECHANICAL. 15. New buttons have been added for the commands *set_post_procedure on/off (menu button POST PROCEDURE) and its associated command *post_procedure_file <procedure filename> (menu button FILE) in the RESULTS menu. 16. New menus have been created to support the creation of MPEG and AVI (Windows NT only) movie files. They are located under the RESULTS MORE ANIMATION menu as MPEG MOVIE and AVI MOVIE. 17. The PARTICLE TRACKING menu under RESULTS MORE PARTICLE TRACKING has been updated to allow for the selection of any SCALAR value that contains the particle tracking information. 18. The RUN JOB menu has been extensively updated in this version of MSC.Marc Mentat. The job_monitor command is now automatically issued when a job is submitted. Some buttons are only displayed when certain options are on: The USE DDM option is only visible if domains have been created. The DDM options for SINGLE MACHINE, NETWORK, and SETTINGS are only visible when the USE DDM option is on. The EDIT and CLEAR buttons are only visible when a USER SUBROUTINE has been specified.

47 Description of the New Functionalities MSC.Marc Mentat Menu Enhancements 43 Many of the buttons have been moved to a new submenu ADVANCED JOB SUBMISSION: The SUBMIT 2 and SUBMIT 3, and EXECUTE 1-3 buttons. The EXTENDED PRECISION button. The DCOM and HOSTNAME button. The WRITE INPUT FILE and EDIT INPUT FILE buttons. The MEMORY ALLOCATION, CHECK SIZES, and OUT-OFCORE ELEMENT STORAGE (elsto) buttons. New items in the ADVANCED JOB SUBMISSION menu are: The SCRATCH DIRECTORY for the job may now be specified. This is where any intermediate files will be created. The input file version may now be specified in this menu. The default is DEFAULT STYLE. Previously this option was only available in the JOB PARAMETERS menu. The table format may be specified in this menu with the NEW STYLE TABLES button. The default is the old style table format. Turn on this option to have the input files written out in the new multi-dimensional table style. 19. The PLOT menu has been revised by relocating items to submenus under each available plot setting. The toggle menu to turn on or off the plotting of the items remains in the top menu. 20. The availability of Shape Memory Alloy materials can be found under the MATERIAL PROPERTIES (MECHANICAL MATERIALS) MORE SHAPE MEMORY ALLOY menus. 21. The menus for the creation of structures using the new CAVITY elements can be found under the MESH GENERATION menu.

48 44 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements 13. MSC.Marc Mentat Preprocessing Enhancements 1. MSC.Ma rc Mentat Preprocess ing Enhancem ents A. Attach 1. A new attach concept has been implemented in MSC.Marc Mentat. Previously, nodes could be attached either to a point, or to a single curve or to one or two surfaces (the latter via the *attach_node_intersect command). This concept had serious limitations, especially for cases where nodes were lying on multiple curves and/or surfaces. Such nodes could not be associated with all these curves and surfaces. In the new attach concept, these limitations have been removed by allowing that A node can be attached to a point; and An element edge can be attached to a curve; and An element face can be attached to a surface. In this setup, nodes can no longer be explicitly attached to curves or surfaces (this will have some effect on existing procedure files, see below). However, every node of an attached edge is now also implicitly attached to the curve to which the edge is attached. Similarly, every node of an attached face is now also implicitly attached to the surface to which the face is attached. Since nodes can be part of multiple edges and faces, they can now be "attached" to multiple curves and surfaces, by attaching the appropriate edges and faces to the curves and surfaces. Furthermore, a node that is "attached" to multiple curves and/or surfaces is now automatically positioned on the intersection of these curves and surfaces (provided the intersection exists). For example, if a node is part of two edges, the first of which is already attached a curve, then attaching the second edge to a different curve will automatically put the node on the intersection of the two curves. 2. All commands that change the position or shape of points, curves or surfaces reposition the nodes attached to these geometric entities. If for some nodes a new position cannot be found because the curves and surfaces to which the nodes are attached do not intersect, then these commands print an error message in the dialog area and do not change the model. No backup is made in that case. Note that this is incompatible with previous MSC.Marc Mentat versions, in which some commands did not reposition the nodes if the geometry changed. 3. All commands that modify the coordinates of nodes do not allow nodes to move off the geometric entities to which they are attached. If this happens, these commands print an error message in the dialog area and do not change the model. No backup is made in that case. Note that this is incompatible with previous MSC.Marc Mentat versions, in which nodes were detached if they were moved to another position. This may have an effect on existing procedure files.

49 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements New attach commands have been added: *attach_nodes_point <point> <node list> *attach_edges_curve <curve> <edge list> *attach_faces_surface <surface> <face list> *detach_edges <edge list> *detach_faces <face list> These commands can be found in the MESH GENERATION ATTACH menu that has been redesigned. The *attach_node_point command is retained for backward compatibility but is no longer available via the ATTACH menu. The attach commands *attach_nodes_curve *attach_nodes_intersect *attach_nodes_surface are now obsolete, but are retained for backward compatibility. However, the commands will no longer attach the nodes to the geometric entities, but will only move them to the curve, the surface or the intersection of two surfaces. This may affect existing procedure files. 5. A new set of move commands has been added for moving a list of nodes to a point, a curve, a surface or to the intersection of two surfaces, similar to the old attach commands. These commands can be found in the new submenu MOVE TO GEOMETRIC ENTITIES of the MESH GENERATION MOVE menu. The existing commands for moving points to curves, surfaces, and the intersection of two surface have been relocated to this new menu as well. 6. The commands *attach_elements_curve (ELEMENTS -> CURVE button) and *attach_elements_surface (ELEMENTS -> SURFACE button) have been changed to attach only the first edge of line elements in the list, respectively, the first face of tria and quad elements in the list, and skip the other elements. 7. The algorithm for projecting nodes or points on the intersection of two surfaces has been improved. This may result in slightly different coordinates of the nodes or points compared to previous MSC.Marc Mentat versions. 8. Attached edges are by default drawn in orange and attached faces are drawn in dark blue. These colors can be changed via the VISUALIZATION COLORS menu. 9. If the drawing of faces is switched off and if initial or boundary conditions are being identified, element edges are now drawn using either the normal edge color or the attach color (whichever is applicable). In previous versions, the edges where drawn using the element face color in this case. 10. The *show_elements (MESH GENERATION->(ELEMS)->SHOW) command now reports for each edge of the element the curve to which it is attached and for each face the surface to which it is attached. The *show_points command reports the number of nodes attached to the point, *show_curves reports the number of edges attached to the curve and the *show_surfaces command report the number of faces attached the surface.

50 46 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements 11. When reading old-style model files (pre-msc.marc Mentat 2003), the old-style attach is converted into new-style attach according to the following rules: a. If a node was attached to a point in the old style, it will also be attached to that point in the new style. b. An edge will be attached to a curve if in the old style, all nodes of the edge are attached to either the curve or one of the end-points of the curve. c. A face will be attached to a surface if in the old style, all nodes of the face are attached either to the surface, or to one of the corner points of the surface, or to a trimming curve of the surface or to a trimming point of the surface. 12. When writing old-style model files, the new-style attach is converted to the old-style attach according to the following rules: a. If a node is attached to a point in the new style, then it will be attached to that point in the old style as well; otherwise b. If a node is part of an edge that is attached to a curve, then in the old style, the node will be attached to that curve; otherwise c. If a node is part of a face that is attached to a surface, then in the old style, the node will be attached to that surface. d. If a node is part of two faces and both are attached to different surfaces, then in the old style, the node will be attached to both surfaces. B. New Combined Mesh/Geometry Commands New commands have been added for moving, duplicating and expanding mesh and geometry simultaneously, while retaining the attach relations between the mesh and the geometry. 1. A command *move_model (MODEL button) has been added to the MESH GENERATION MOVE menu that moves the entire model (mesh, geometry, and links) according to the specified scale factors, rotations, translations, and formulas. 2. The commands *move_combined <mixed item list> *duplicate_combined <mixed item list> *symmetry_combined <mixed item list> *expand_combined <mixed item list> have been added to move, duplicate, and expand a mixed list of mesh items, geometric items and links simultaneously. The list of items can be specified by means of graphical picking (single, box, and polygon pick), command line input or the wildcards all_existing, all_visible, all_invisible, all_selected and all_unselected.

51 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements 47 By default, all available item types for a given command are pickable and accepted by the command. That is, a box pick will pick every node, element, point, curve, surface, solid, nodal tie, servo link and spring (if applicable, see below) inside the box and pass those on to the command. Similarly, the all_visible wildcard will pick every visible node, element, point, curve, surface, solid, nodal tie, servo link, and spring. The commands *set_move_combined <item type> on off *set_duplicate_combined <item type> on off *set_symmetry_combined <item type> on off *set_expand_combined <item type> on off control the items that are pickable and accepted by a subsequent execution of the corresponding combined command. Here, <item type> is one of nodes elements points curves surfaces solids ties servos springs for the *set_move_combined, *set_duplicate_combined, and *set_symmetry_combined commands and one of nodes elements points curves for the *set_expand_combined command. For example, *set_duplicate_combined curves off switches off duplication of curves by the *combined_duplicate command. Curves will not be pickable during the execution of the command and the wildcards will not include any curves. The *move_combined command preserves the attach relations between the mesh entities and the geometric entities during the move. The *duplicate_combined and *symmetry_combined commands duplicate the attach relations between mesh and geometric entities and the *expand_combined command expands the attach relations. For example, if an edge is attached to a curve then *duplicate_combined attaches the duplicates of the edge to the corresponding copies of the curve, while *expand_combined attaches the faces that result from expansion of the edge to the surfaces that result from expansion of the curve. These commands can be found in the respective menus in MESH GENERATION (also see the items on these menus on the following pages).

52 48 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements C. Modifications to Mesh Generation Commands Several mesh generation commands that replace existing elements by one or more new elements have been enhanced or rewritten to transfer the attach information from the old elements to the new elements. 1. The CHANGE CLASS operation has been reimplemented. A new command *change_elements_class has been added that replaces the existing *change_elements command. The difference between the two commands becomes apparent when new midside nodes have to be created on edges or faces of elements, for example, to change them to higher-order elements. The old *change_elements command creates multiple coinciding nodes on coinciding edges or faces of different elements that have to be merged by a subsequent *sweep_nodes command. The latter may inadvertedly merge nodes of different regions (contact bodies, for example). By contrast, the new *change_elements_class command first identifies coinciding edges and faces (edges and faces that share the same nodes) and then creates a unique midside node that is shared by the neighboring elements. This implies that a subsequent *sweep_nodes operation is no longer necessary. A new command *change_elements_linear has been added that changes existing higher-order elements to lower-order, irrespective of their class. Similarly, the new command *change_elements_quadratic changes existing lower-order elements to higher-order. Like the *change_elements_class command, the latter creates unique midside nodes on coinciding edges. The advantage of using these two new commands lies in the fact that changing elements of different classes to their linear or quadratic counterpart can be done in a single operation, and a subsequent *sweep_nodes operation is no longer necessary. All CHANGE CLASS commands transfer attach information from the original element to the newly created element(s) for all available conversions. Also, when changing to elements of a different family (quad4 to tria3, for example), set information is transferred properly (this used to be wrong in some cases). When changing from first-order element classes to second-order or semi-infinite element classes, the newly created mid-edge nodes are now positioned on the curves to which the edges of the original element are attached, or, if they are not attached to any curve, on the surfaces to which the faces of the edges are attached. The position is determined such that the mid-edge node divides the edge in two parts of equal lengths. When changing to semi-infinite element classes, the newly created midface nodes are now positioned on the surfaces to which the faces are attached (if any). Cases in which the edge is attached to a closed curve or in which the face is attached to a closed surface are handled correctly now. This used to be wrong in previous MSC.Marc Mentat versions. If the nodes of an edge were attached to a closed curve, the mid-edge node could be positioned wrongly if the edge would pass the begin and end point of the curve. The old *change_elements command can no longer be accessed from the menus, but is retained for backward compatibility.

53 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements The *convert_curves command now attaches the edges of the line elements to the curves and the nodes at the end points of the curve to the points. Similarly, *convert_surfaces now attaches the faces of the quad elements to the surface and the nodes at the corner points of the surface to the points. 3. The commands *line_expand and *shell_expand now expand the elements in the direction of the normal to the curve or surface to which the first edge or first face of the line elements or shell elements is attached (if any). 4. Subdivide has been completely rewritten to transfer as much as possible of the attach information: The nodes created at the position of the corner nodes of the original element will inherit the properties (attach info, sets, initial conditions, boundary conditions, transformations) of the corner nodes. For elements with mid-edge/mid-face/mid-element nodes (second-order or semi-infinite element classes), subdivide will create a node at exactly the same position as the mid-edge/mid-face/mid-element node if the latter is attached to a point. These newly created nodes will inherit the properties (attach info, sets, initial conditions, boundary conditions, transformations) of the former in that case. If the bias factor is zero, any subdivision will create a node at the position of the mid-edge/mid-face/mid-element node of the original element. However, if the bias factor is not zero, this is not always true. In that case, the bias factor will be adjusted a little (for that edge/face/element only) and a warning message will be displayed in the dialog area. If an edge of the original element is attached to a curve, the edges of the elements of the subdivision that lie on the edge of the original element will be attached to that curve. If a face of the original element is attached to a surface, the faces of the elements of the subdivision that lie on the face of the original element will be attached to that surface. If an edge of the original element is attached to a closed curve, the newly created nodes of the subdivision on that edge are now positioned on the part of the curve that is closest to the centroid of the original edge, instead of simply between the curve coordinate of the first node of the edge and the curve coordinate of the last node of the edge, as in previous versions. This fixes a bug that has been present in the code for a long time. This applies to both the normal *subdivide_elements command and the two special commands *subdivide_elements2hex and *subdivide_elements2quad. In previous versions, the latter didn't transfer any data from the original element to the newly created elements at all. 5. Refine has been completely rewritten to transfer as much as possible of the attach and set information (hence also boundary conditions) from the original element to the new elements: Edge and face set information is now transferred from the original elements to the new elements. Consequently, if an edge load is applied to an edge of the original element, the edges of the new elements that lie on that edge will inherit the edge load. Similarly, if a face load is applied to a face of the original element, the faces

54 50 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements of the new elements that lie on that face will inherit the face load. Node and element set information was already transferred. If an edge of the original element is attached to a curve, the edges of the new elements that lie on the edge of the original element will be attached to that curve. If the curve is closed, the newly created nodes on that edge are now positioned on the part of the curve that is closest to the centroid of the original edge, instead of simply between the curve coordinate of the first node of the edge and the curve coordinate of the last node of the edge, as in previous versions. This fixes a bug that has been present in the code for a long time. If a face of the original element is attached to a surface, the faces of the new elements that lie on the face of the original element will be attached to that surface. For consistency with subdivide, *refine_node now operates in the user coordinate system instead of in the global coordinate system as before. This implies that the resulting subdivision of the original elements depend on the coordinate system type (RECTANGULAR, CYLINDRICAL, SPHERICAL). This may affect existing procedure files. 6. Expansion of axisymmetric meshes to three-dimensional meshes (*expand_axito3d) has been improved to expand attach information: If an edge of the axisymmetric mesh is attached to a curve, the faces that result from expanding the edge in the circumferential direction, will be attached to the surface that results from revolving the curve. If a node of the axisymmetric mesh is attached to a point, the point is expanded into a circle and the edges that result from expanding the node in the circumferential direction are attached to the circle. If the point is not a trimming point of a surface, the node remains attached to the point. Otherwise, a new point will be created with the same global position as the trimming point and the node will be attached to the new point. 7. The MESH GENERATION menus MOVE, DUPLICATE, SYMMETRY, and EXPAND have been redesigned. Displays have been replaced by editable text fields, so that the parameters that govern these operations (centroid, scale factors, rotation angles, etc.) can be set individually. Commands: *set_move_trans_from_to <x1> <y1> <z1> <x2> <y2> <z2> *set_duplicate_trans_from_to <x1> <y1> <z1> <x2> <y2> <z2> *set_expand_trans_from_to <x1> <y1> <z1> <x2> <y2> <z2> have been added to set the translation vector T for move, duplicate, and expand operations, respectively, to the relative position of (x2, y2, z2) with respect to (x1, y1, z1), that is T = (x2 - x1, y2 - y1, z2 - z1). Both (x1, y1, z1) and (x2, y2, z2) may be entered by clicking on grid points, points, or nodes. The commands are useful if one wants to move items from one point in the model to another.

55 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements 51 Similarly, the new command *set_symmetry_plane_normal_from_to <x1> <y1> <z1> <x2> <y2> <z2> sets the normal vector N for symmetry operations to the direction from (x2, y2, z2) to (x1, y1, z1), that is N = (x2 - x1, y2 - y1, z2 - z1) / (x2 - x1, y2 - y1, z2 - z1). Again, both (x1, y1, z1) and (x2, y2, z2) may be entered by clicking on grid points, points, or nodes. 8. Duplication of trimmed surfaces has changed. Previous MSC.Marc Mentat versions did not create exact copies of the trimming points and trimming curves of a surface. For each trimming curve, the complete set of points was duplicated, even if some of these points were shared by other trimming curves of the same surface. For example, if two trimming curves of the original surface had an end point in common, this was not the case for the duplicates. Two points were created at the same position in that case. This is fixed in MSC.Marc Mentat The trimming points and curves are now duplicated exactly. However, this means that a different number of trimming points may be created when duplicating trimmed surfaces and may affect existing procedure files. This applies to all DUPLICATE and SYMMETRY commands that copy trimmed surfaces. 9. The curves and surfaces created by the *symmetry_curves and *symmetry_surfaces commands now have the same orientation as their originals. This is incompatible with previous MSC.Marc Mentat versions, in which the new curves and surfaces were flipped compared to the originals. The command *set_symmetry_geometry_old on restores the old (pre-msc.marc Mentat 2003) behavior of these commands and should be called in existing procedure files prior to such a symmetry operation, to ensure that the procedure file still produces the same model. D. Modifications to the Automatic Meshers The automatic meshers have been enhanced for the new attach concept. 1. The 2-D meshers now attach all edges on the boundary of the mesh to the appropriate curves. Both the advancing front mesher and the overlay mesher also attach nodes that are located on the end points of the curves to these points. 2. The surface meshers now attach all element faces to the surface and attach all edges on the boundary of the mesh to the appropriate trimming curves. Both the advancing front mesher and the overlay mesher also attach nodes that are located on the end points of the trimming curves to these points. 3. The overlay mesher has been modified to compute the sizes of the elements in the U- and V-directions in a more intuitive way that is also more in agreement with the hexahedral mesher. In previous MSC.Marc Mentat versions, the mesher would create a rectangular grid on a square region that just covers the region to be meshed, using the overlay divisions in the respective directions. If the number of divisions in U- and V- directions were equal, square elements would result. In MSC.Marc Mentat 2003, the

56 52 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements element size in U-direction is computed independently of that in the V-direction as the ratio of the largest U-dimension of the region and the overlay divisions in U-direction. The element size in the V-direction is determined similarly. This greatly improves meshing of slender regions. As a result, MSC.Marc Mentat 2003 may produce a different mesh for a given geometry and overlay divisions than previous MSC.Marc Mentat versions. The command *set_overlay_old_div on restores the old (pre-msc.marc Mentat 2003) behavior of the mesher. This command should be called in existing procedures files prior to the mesher to ensure that the procedure file still produces the same model. 4. The tetrahedral mesher and the new MSC.Patran mesher attach element faces on the surface of the tetrahedral mesh to the surfaces to which the faces of the original surface mesh were attached. E. New Automatic Meshers from MSC.Patran The MSC.Patran Mesh-on-Mesh (MOM) surface mesher and tetrahedral solid mesher are now available in MSC.Marc Mentat. This mesher is fast and can handle complex geometry much better than the standard MSC.Marc Mentat mesher. 1. MSC.Patran Mesh-on-Mesh Surface Mesher The surface mesher can be accessed through menu MESH GENERATION AUTOMESH SURFACE MESHING PATRAN SURFACE MESHER. This function is used for remeshing the given list of surface triangle elements or geometry defined by triangles such as that in STL format. The element size for surface mesher can be set through the button ELEMENT SIZE. If the element size is set to 0, the average size of the input elements will be used. The new elements will have edges of approximately this length. In addition to the mesher size, there are 2 more parameters the user can use to control the feature of mesh. They are feature edge angle and feature vertex angle and can be set in the ADVANCED menu through button FEATURE EDGE ANGLE and FEATURE VERTEX ANGLE. If the angle between normal vectors of two neighboring surfaces of an edge is larger than feature edge angle, the edge will be considered as a soft feature edge. A soft edge will be kept after the remeshing but new nodes can be placed on the edge. If two feature edges join at a point and the angle between the two feature edge vectors pointing outward of the point is smaller than feature vertex angle, the point will be considered as a hard point. A hard point will be kept as an element node after remeshing. 2. MSC.Patran Tetrahedral Solid Mesher The solid mesher can be accessed through menu MESH GENERATION AUTOMESH SOLID MESHING PATRAN TET MESHER. This function is used for meshing the volume defined by the given list of triangle surface elements. The input surface elements must completely enclose the volume to be meshed. The coarsening factor can be used to gradually enlarge the tetrahedral element size from the surface to the interior region.

57 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements 53 The coarsening factor can be set through the button COARSENING FACTOR. The elements will be enlarged by this factor from the surface to the interior layers. The default is 1.5. F. Model Parameters 1. The following commands that set the value of model parameters will now check by default the validity of the value before changing the parameter: BOUNDARY CONDITIONS menu: *apply_value *apply_param_value (NEW) *apply_variable *apply_post_increment *apply_post_steps INITIAL CONDITIONS menu: *icond_value *icond_param_value (NEW) *icond_variable *icond_post_increment *icond_post_time *icond_exp_repetitions LINKS SPRINGS menu: *link_value *spring_param (NEW) *spring_multi_param (NEW) *link_multi_spring_stiffness *link_multi_spring_damping *link_multi_spring_init_force CONTACT CONTACT BODIES menu: *contact_value CONTACT CONTACT TABLES menu: *contact_table_property LOADCASES menu: *loadcase_value JOBS menu: *job_param If the value is outside the valid range of the parameter, an error message is displayed in the dialog area and the parameter is not changed. This allows MSC.Marc Mentat to detect any user errors as early as possible. The command *set_model_validation on off can be used to switch range checking off. If it is switched off, the above commands also accept values outside the valid range of the parameter. This may be useful if a parameter is used in a non-standard way.

58 54 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements G. Multidimensional Tables 1. Independent Variables The tables in MSC.Marc Mentat have been enhanced to allow multiple independent variables. In previous versions, tables had 1 independent variable. The physical meaning of the independent variable was defined by setting the table type. In this release, a table may have up to 4 independent variables, each having a different physical meaning. The type must be set for each independent variable individually. Use the button TYPE (command: *set_md_table_type <indep_var> <type>) to set the type for the current independent variable. Note that for tables with multiple independent variables, the current independent variable in the menu can be changed using the INDEPENDENT VARIABLE pulldown menu. The number of available types has been increased. Also, the names of some types have been changed: plastic_strain has been renamed to eq_plastic_strain stress has been renamed to eq_stress strain rate has been renamed to eq_plastic_strain_rate gasket_closure rate has been renamed to gasket_closure_distance stress_rate has been corrected to eq_stress The old command *set_table_type can still be used to set the type for tables with 1 independent variable. Note that this command still expects the old table type names, which means that this command will be processed correctly if old procedure files are run. When reading an old model file or table file ("normal" format), the old types are mapped automatically to the new types. The inverse operation is done when saving a model in an older format. The independent variables are referred to as v1, v2, v3, and v4. In previous versions, the independent variable was referred to as x. The number of steps and the range used to plot the axis of the current independent variable can be set using the buttons STEPS (command: *set_md_table_step_v <indep_var> <nsteps>), MIN (command: *set_md_table_min_v <indep_var> <vmin>) and MAX (command: *set_md_table_max_v <indep_var> <vmax>) from the INDEPENDENT VARIABLE menu section. The MORE button must be used to access the buttons LABEL (command: *set_md_table_label_v <indep_var>) and FORMULA (command: *set_md_table_formula_v <indep_var>) from the INDEPENDENT VARIABLE menu section, that allow changing the label displayed along the axis of the current independent variable. The old commands *set_table_xstep, *set_table_xmin, *set_table_xmax, *set_table_xname, and *table_xformula may still be used for tables with 1 independent variable. Note that the old command *table_xformula still expects a

59 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements 55 formula expressed in x and then converts the formula to v1, which means that this command will be processed correctly if old procedure files are run. When reading an old model file or table file ("normal" format), the label formula in x is automatically converted into a formula expressed in v1. The inverse operation is done when saving a model in an older format. 2. Dependent Variables For most tables, the number of dependent variables is 1. The exception is formed by tables for experimental data fitting that may have 2 dependent variables. The number of independent variables for these tables is always 1. Tables with 2 dependent variables were already supported in previous MSC.Marc Mentat versions, but they could only be created by reading raw table data. Moreover, the second function value could neither be displayed nor edited. In this release, tables with 1 independent and 2 dependent variables can be created in MSC.Marc Mentat, and the second function value can now be displayed and edited. Note that for tables with multiple dependent variables, the current dependent variable in the menu can be changed using the FUNCTION VALUE pulldown menu. The dependent variables are referred to as f and f2. In previous versions, the dependent variable was referred to as y. The number of steps and the range used to plot the axis of the current dependent variable can be set using the buttons STEPS (command: *set_md_table_step_f <dep_var> <nsteps>), MIN (command: *set_md_table_min_f <dep_var> <fmin>) and MAX (command: *set_md_table_max_f <dep_var> <fmax>) from the FUNCTION VALUE menu section. The MORE button must be used to access the buttons LABEL (command: *set_md_table_label_f <dep_var>) and FORMULA (command: *set_md_table_formula_f <dep_var>) from the FUNCTION VALUE menu section, that allow changing the label displayed along the axis of the current dependent variable. The old commands *set_table_ystep, *set_table_ymin, *set_table_ymax, *set_table_yname, and *table_yformula may still be used for tables with 1 independent variable. Note that the old command *table_yformula still expects a formula expressed in y and then converts the formula to f, which means that this command will be processed correctly if old procedure files are run. When reading an old model file or table file ("normal" format), the label formula in y is automatically converted into a formula expressed in f. The inverse operation is done when saving a model in an older format. 3. Creating a Table When creating a table, use the NEW button to open up the NEW TABLE pulldown menu, and select one of the buttons to set the number of independent and dependent variables (command: *new_md_table <# indep_vars> <# dep_vars>). The old command *new_table can still be used to create a table with 1 independent and 1 dependent variable.

60 56 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements 4. Reading and Writing Table Data Another way of creating a table is by reading data from a file. Two file formats are available for reading (and writing) table data. The "raw" format (commands: *md_table_read_raw <file name> and *md_table_write_raw <file name>) can only be used for tables with 1 independent variable. Each line in the raw file represents one table point. The first column contains the value of the independent variable, the second column contains the value of the dependent variable (function value). For tables with 2 dependent variables, a third column contains the second function value. The "normal" table file format (commands: *md_table_read <file name> and *md_table_write <file name>) has been enhanced to contain all data of the new multidimensional tables. The old commands *table_read and *table_write may still be used to read and write data for tables with 1 independent variable and 1 dependent variable using the "normal" table file format of the previous MSC.Marc Mentat versions. 5. Multiplying Tables A third method has been added to create a table: multiplication of two tables. The number of independent variables of the new table is the sum of the number of independent variables of the two original tables. If the sum exceeds 4, the operation is not performed. The function values of the new table are computed as Fnew(v1, v2, v3) = F1(v1) * F2(v2, v3). 6. Data Points vs. Formula Apart from reading data points from a file, table points can be generated by adding data points manually or evaluating a formula. Adding data points manually for tables with 1 independent variables must be done using ADD (command: *table_add). The user must enter the value of v1 and f (and f2 in case of 2 dependent variables). This command existed already in previous versions of MSC.Marc Mentat and can be repeated as often as needed. Adding data points manually for tables with multiple independent variables must be done using the new command ADD ALL POINTS (command: *md_table_add_all). The user is prompted for the number of data points for each independent variable. Next, the user must enter the values of each independent variable. Finally, the user is expected to enter all function values. Note that currently for tables with multiple independent variables, no new data points can be added if data points already exist. To enable the use of a formula, the user must now first select FORMULA (command: *set_md_table_method_formula). Then, the ENTER button must be clicked and a formula must be given expressed in v1, v2, v3 and/or v4 (command: *md_table_formula). Data points are created by evaluation of the formula using the number of steps and the range for each independent variable. Reevaluation of the formula is done using REEVALUATE (command: *md_table_reeval). The old commands *table_formula and *table_reeval may still be used for tables with 1 independent variable. Note that the command *table_formula still expects a formula expressed in x and then converts the formula to v1, which means that this command will be processed correctly if old procedure files are run. When reading an old

61 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements 57 model file or table file ("normal" format), the formula in x is automatically converted into a formula expressed in v1. The inverse operation is done when saving a model in an older format. 7. Plotting The FILLED option for table plots is now off by default. For tables with more than 1 independent variable, the X-AXIS pulldown menu has been added to select which independent variable is displayed along the X-axis of the plot. The other independent variable is displayed along the Y-axis of the plot. A curve is drawn for each data point value of the independent variable that is displayed along the Y-axis. For tables with more than 2 independent variables, the Y-AXIS pulldown menu has been added to select which independent variable is displayed along the Y-axis of the plot. For the third independent variable, a fixed value is taken, namely the i-th data point value for this independent variable. The index i ranges from 1 to the number of data points of the independent variable and can be set using the FIX button (command: *set_md_table_fix_index <indep_var> <i>). For tables with 4 independent variables, a second FIX button has been added to fix the value of the fourth independent variable. 8. Data Storage The data storage of tables has been enhanced to use dynamic memory allocation. Previous versions used fixed size arrays to store the data point values, the number of data points being limited to H. New Table Style Input The new multidimensional tables have been designed to support the new table style input of MSC.Marc. However, this new style input is not the default input style of this release. It can be activated by switching on the NEW-STYLE TABLES toggle (command: *job_option input_style:new). This button is available in the JOBS... JOB PARAMETERS menu and the JOBS RUN ADVANCED JOB SUBMISSION menu. The menu items supporting MSC.Marc input options that are only available in combination with the new style input are hidden by default. To fully uncover all possibilities of the new style input, MSC.Marc Mentat must be run using a different binary menu file. To create this binary menu file, go to the directory where MSC.Marc Mentat is installed and enter the following command:./bin/mentat -df NEW_INPUT -compile menus/new.msb To run MSC.Marc Mentat using this binary menu file, enter the following command: mentat -mf new.msb

62 58 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements I. Referencing Tables with Multiple Independent Variables When new style input is used, tables with multiple independent variables may be referenced by any parameter for which a TABLE button is available. If the default style input is used, tables with multiple independent variables may only be used for a limited set of parameters: Material parameters previously referring to multiple tables (see below) Equivalent creep strain rate (see below) Gasket material parameters Spring parameters 1. Material Parameters Previously Referring to Multiple Tables In previous versions, the user could assign multiple tables to the following material parameters: PLASTICITY material: INITIAL YIELD STRESS (commands: *material_table plasticity:yieldstress0 1 2) 10TH CYCLE YIELD STRESS (commands: *material_table plasticity:yieldstress100 1) FLUID material: VISCOSITY (commands: *material_table fluid:nt_viscosity0 1) POWDER material: YOUNG S MODULUS (commands: *material_table powder:youngs_modulus0 1) POISSON S RATIO (commands: *material_table powder:poissons_ratio0 1) CONDUCTIVITY (commands: *material_table powder:conductivity0 1) SPECIFIC HEAT (commands: *material_table powder:specific_heat0 1) In the current release, a parameter can only have 1 table assigned to it (commands: *material_param_table plasticity:yield_stress, etc.). For the material parameters mentioned above, this means that a table with multiple independent variables must be selected in cases where previously multiple tables would have been selected. If, during reading of an old model file, any of the above mentioned parameters is found that references multiple tables, a new table with multiple independent variables is automatically created and assigned to this parameter. This new table is created by multiplication of the tables that were being referenced by the parameter, as discussed in the section "Multiplying Tables". Note that old procedure files, in which multiple tables are assigned to any of the above mentioned parameters, will not run correctly anymore. Edit the procedure file such that the tables are multiplied and the resulting table is assigned to the parameter.

63 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements Equivalent Creep Strain Rate In previous versions, the dependency of the equivalent creep strain rate on stress, creep strain, temperature, and time could be defined separately. For each dependency, the user could choose between a power law formulation or a piecewise linear formulation referencing a table (commands: *material_option creep:stress:power series, etc.). As a consequence, the user could reference up to 4 tables to define the creep behavior (commands: *material_table creep:stress_exp0, etc.). In the current release, this has been changed. There is one option to switch between power law and piecewise linear (command: *material_option creep:method:default pwlinear), and only 1 table can be referenced for the piecewise linear method (command: *material_param_table creep:coefficient). This means that, for creep material definition, a table with multiple independent variables must be selected in cases where previously multiple tables would have been selected. If, during reading of an old model file, a creep material definition is found that references multiple tables, a new table with multiple independent variables is automatically created and assigned to the "coefficient" parameter. This new table is created by multiplication of the tables that were being referenced in the old material definition, as discussed in the section "Multiplying tables". In addition, the material option "method" is set to "pwlinear" if any of the dependencies was using the piecewise linear method. Note that old procedure files, in which multiple tables are referenced in a creep material definition, will not run correctly anymore. Edit the procedure file such that the tables are multiplied and the resulting table is assigned to the "coefficient" parameter, and make sure the material option "method" is set to "pwlinear". J. Passing a Table Formula to MSC.Marc; Extrapolation Flag When new style input is used, tables defined by means of a formula instead of a set of data points are treated differently. The formula is passed to MSC.Marc, which evaluates the tables during the analysis. To activate this feature, the table method must be set to FORMULA (command: *set_md_table_method_formula) and a formula must be given in terms of v1, v2, v3 and/or v4. If the formula method has been used to create data points but the formula should not be passed to MSC.Marc while using the new style input, you must set the table method back to DATA POINTS (command: *set_md_table_method_data_points). When new style input is used and the table method is set to DATA POINTS (command: *set_md_table_method_data_points), the user may indicate for each independent variable whether MSC.Marc must perform extrapolation of data in case the independent variable value is outside the range of data points (command: *set_md_table_extrap <indep_var> on). If this option is off, the value at the closest data point is taken. If the default input style is used, the use of both these features is only allowed for: Gasket material parameters Spring parameters Forming limit parameter (Table method)

64 60 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements K. Electromagnetic Boundary Conditions Four new boundary condition types have been added such that the old types FIXED POTENTIAL POINT CURRENT-CHARGE could be split up in two types each: FIXED ELECTRIC POTENTIAL FIXED MAGNETIC POTENTIAL POINT CHARGE POINT CURRENT (*apply_type fixed_elma_potential) and (*apply_type point_current_charge) (*apply_type fixed_elma_elec_potential), (*apply_type fixed_elma_magn_potential), (*apply_type elma_point_charge) and (*apply_type elma_point_current). This allows defining the electric and magnetic boundary conditions independent of one another. Upon importing old model files, the old types are converted to the new types. If a model file must be written in a pre-2003 style, it is advisable to change the new types of electromagnetic boundary conditions to the old types before saving the model. L. Harmonic Boundary Conditions The modeling of boundary conditions for harmonic loadcases has changed. In this release, separate boundary condition types for harmonic excitations have been added. These new types can be found in the HARMONIC BC s submenus of the MECHANICAL, ELECTROSTATIC, ACOUSTIC, and ELECTROMAGNETIC boundary condition menus. For these new types, the user may now set the INPUT MODE to either MAGNITUDE & PHASE or REAL & IMAGINARY (command: *apply_option harmonic_mode:magn_phase real_imag). Harmonic boundary conditions can only be selected in harmonic loadcases. They cannot be selected in loadcases of other types, nor can they be selected as initial load. In a harmonic loadcase, the user may select both harmonic boundary conditions and normal boundary conditions. A normal boundary condition has a constant value during the harmonic loadcase, while a harmonic boundary condition represents a load that is oscillating at the current frequency. In previous MSC.Marc Mentat versions, all boundary conditions selected in a harmonic loadcase were considered to be harmonic boundary conditions. Also, in previous versions, the phase angle of a harmonic boundary condition could be set per loadcase; this is no longer the case as the phase is now set for a boundary condition. It is possible though to assign a table of type "time" to the magnitude, phase, real part and imaginary part. When reading older model files, the type of boundary conditions only used in harmonic loadcases is changed to the equivalent new harmonic type, and the phase is inherited from the harmonic loadcase. If a model file must be written in a pre-2003 style, it is advisable to change the types of harmonic boundary conditions to their non-harmonic equivalents before saving the model. Please check carefully if old procedure files, in which harmonic boundary conditions are applied, are still running correctly.

65 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements 61 M. Nodal Ties, Servo Links, and Springs Several enhancements have been made to the support for nodal ties, servo links, and springs. 1. The limitations on the number of retained nodes for user defined tyings (via user subroutine UFORMS) and the number of terms for servo links has been removed. These multi-point constraints can now have any number of retained nodes. In previous MSC.Marc Mentat versions, the limit was The LINKS NODAL TIES, LINKS SERVO LINKS, and LINKS SPRINGS menus have been redesigned. Displays have been replaced by editable text fields and buttons have been introduced for setting the degrees of freedom of a servo link or spring node. 3. New commands have been added to move, duplicate, duplicate by reflecting with respect to a plane (symmetry) and remove lists of nodal ties, servo links and springs. These lists can be specified by means of graphical picking (using the usual single pick, box pick, or polygon pick methods), command line input, or the wildcard all_existing. The wildcards all_invisible and all_selected are not yet available for links; the wildcards all_unselected and all_visible are currently identical to all_existing. The new remove commands: *remove_ties <ties list> *remove_servos <servos list> *remove_springs <springs list> can be found in the LINKS NODAL TIES, LINKS SERVO LINKS, and LINKS SPRINGS menus, respectively. The new move commands: *move_ties <ties list> *move_servos <servos list> *move_springs <springs list> duplicate commands *duplicate_ties <ties list> *duplicate_servos <servos list> *duplicate_springs <springs list> and duplicate by symmetry commands *symmetry_ties <ties list> *symmetry_servos <servos list> *symmetry_springs <springs list> can be found in the respective menus in MESH GENERATION (also see the items on these menus below). The new mesh generation commands behave similar to the corresponding commands for elements. 4. MSC.Marc Mentat will now draw lines between the tied node and all nonzero retained nodes of nodal tyings and servo links. Previously, these lines were drawn only between the tied node and the first nonzero retained nodes, until a zero retained node was found.

66 62 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements N. Enhancement of Domain Decompositiont 1. The Domain Decomposition are enhanced by 3 new methods: Metis Element Based, Metis Node Based, and Metis Best (combined Metis Element Based and Metis Node Based). These 3 methods are based on the implementation of the well known Metis Graph Decomposition Methods. 2. Metis based methods are robust and produce good quality domains. 3. The former DECOMPOSE button is now represented by the Geometric DDM method. The former GENERATE button is now represented by the Simple DDM method. The actual decomposition is performed by the GENERATE! button. Figure 42: Domain Decomposition Menu and Example Model

67 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements 63 Figure 43: Domain Decomposition Menu with Pop-up Metis Buttons O. Job Submission MSC.Marc jobs are now run from the directory in which the model file was read. The log file, scratch files, and the post file will be created in that directory. The SET DIRECTORY command has no effect on the location of these files. The location for the scratch files may be changed using the scratch_directory command in the JOBS RUN ADVANCED JOB SUBMISSION menu. P. Python The ability to obtain a user-defined string from MSC.Marc Mentat in a Python script has been added. The user can specify the string using the PARAMETERS menu, and the Python script obtains the value using the py_get_string routine. The following example uses the model file in Chapter 7 of the MSC.Marc Python Tutorial and prints out the number of sets in the model. The steps for this example are: Browse to the Python examples directory. Specify the name of the model file that we want to check. Run the Python script. UTILS CURRENT DIRECTORY mentat2003/examples/python/tutorial/c07 OK PARAMETERS (NAME) filename

68 64 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements (EXPRESSION) sets.mfd OK PYTHON RUN nsets.py The Python script is: 1 from py_mentat import * 2 3 def main(): 4 fn = py_get_string("filename") 5 s = "*open_model %s" % fn 6 py_send(s) 7 n = py_get_int("nsets()") 8 print "Sets found: ",n 9 return if name == main : 12 main() The output of the script will be printed in the terminal window: 13Sets found: 8 Q. Miscellaneous Changes 1. All commands that use bias factors now display an error message in the dialog area if one of the bias factors is invalid, that is, if the bias factor less than or equal to -n/(2*(n-1)) or greater than or equal to n/(2*(n-1)), where n is the number of subdivisions. The model will not be changed in that case and no backup will be made. The affected commands are: MESH GENERATION CONVERT menu: *convert_curves *curve_polylines *curve_interpolated *convert_surfaces *surface_polyquads *surface_interpolated MESH GENERATION STRETCH menu: *stretch_nodes MESH GENERATION AUTOMESH menu: *overlay_mesh *trim_mesh MESH GENERATION SUBDIVIDE menu: *subdivide_elements *subdivide_curves

69 Description of the New Functionalities MSC.Marc Mentat Preprocessing Enhancements On the rare occasion that a contact body has both elements and curves or surfaces, *identify_contact will now only identify the elements of the body if the body is deformable, workpiece, heat_rigid, or acoustic and the curves or surfaces if the body is rigid or symmetry. Previously, it would identify both. 3. Boundary conditions and initial conditions that are applied to geometric entities are now by default drawn on the geometric entities instead of on the attached mesh entities as before. Two new commands: *draw_applys_on_mesh on off *draw_iconds_on_mesh on off have been added that allow switching back to the old behavior. These commands can be found in the BOUNDARY CONDITIONS menu and the INITIAL CONDITIONS menu, respectively. 4. The command *identify_applys now draws arrows for every boundary condition, regardless of whether *set_applys is on or off. Previously, *identify_applys displayed the legend, but no arrows if *set_applys was off. Similar for initial conditions. 5. MSC.Marc Mentat has been enhanced to be a full 64 bit compliant application for use on SGI Irix 64, Sun Solaris 2.8, Compaq Tru64, HP bit, IBM AIX 5.1 and Linux This allows for much larger models to be created and post processed, up to 2 billion nodes. 6. The file specified on the command line to be opened may now include any file type that MSC.Marc Mentat recognizes in addition to the.mfd and.mud files: MSC.Marc Input File (.dat), AutoCad (.dxf), NASTRAN (.bdf,.nas), PATRAN (.pat), C-MOLD (.par), ACIS (.sab,.sat), STL (.stl), Ideas (.unv), VDA-FS (.vda).

70 66 Description of the New Functionalities MSC.Marc Mentat Postprocessing Enhancements 14. MSC.Marc Mentat Postprocessing Enhancements A. MPEG and AVI Animation MSC.Marc Mentat can now create an MPEG animation file or an AVI (Windows NT/2000/XP only) animation file. It is accessed from the RESULTS ANIMATION submenu. The settings are preset to typical default values so that for most users, only one button needs to be pressed to start the creation of the animation file. The MPEG and AVI animation menus are very similar. The BASE FILE NAME is automatically set to the name of the post file. The GENERATE ANIMATION FILES button enables or disables the creation of the intermediate display list files that are read and displayed when selecting the PLAY button in the ANIMATION main menu. In most cases, you will want to have this option selected unless you are assembling an animation from various increments in the post file. The buttons under the INCREMENTS section are the same as in the RESULTS main menu. The ATTRIBUTES menu provides shortcuts to the LEGEND settings, RANGE and COLORMAP buttons. The CLEAN FILES button will remove all the intermediate display list files and the PPM image files used to create an MPEG movie. Do not use this button until you have successfully viewed the resulting animation file. Figure 44: MPEG and AVI Animation Menus The DELAY button in the MPEG menu will duplicate frames (increment images) in the MPEG movie since some MPEG players will attempt to play the movie in real time. For example, if there are 100 increments, some MPEG players will skip frames to try and play the entire movie in 100/24fps = 4 seconds.

71 Description of the New Functionalities MSC.Marc Mentat Postprocessing Enhancements 67 When the MAKE MPEG MOVIE button is pressed, the intermediate display list files are generated, then they are played back and images are created from each of the increments and stored in the PPM graphic files. Then the MPEG encoding program, mpeg_encode.exe in MSC.Marc Mentat s bin directory, is run in the background. Note that there is no feedback from this program back to MSC.Marc Mentat to indicate that the MPEG encoder has completed. The most reliable way to detect this is to use the ps command on Unix or the Windows Task Manager on Windows NT. You can also monitor the size of the MPEG file: when it is no longer growing in size the encoder has completed generating the file. The COMPRESSION DIALOG button in the AVI menu allows you to select the compression method for the AVI file. In most cases, you will NOT want to select the default of Full Frames (Uncompressed). You should select Microsoft Video 1 as the compression method. When the MAKE AVI MOVIE button is selected, it performs tasks similar to that for the MPEG movie. The intermediate display list files are generated, and then they are played back and images are created. However, these images are not saved to a file. They are fed immediately to the AVI movie generator. When all of the display list files have been displayed and images created, the AVI movie generator will write the AVI file to disk. B. Post Procedure File New commands have been added named *set_post_procedure on/off (menu button POST PROCEDURE) and its associated command *post_procedure_file <procedure filename> (menu button FILE) in the RESULTS menu. These commands allow for the specification of a procedure file whose contents will be executed as each increment is read. This is most useful when a 2-D analysis has been run and a 3-D model is desired to be viewed based on symmetry. For example, the MSC.Marc User s Guide, Chapter 10 problem of a tire analysis produces a 2-D section of the tire. To build a full 3-D model, place the following commands in a procedure file and select it using the FILE button: *clear_mesh *set_expand_rotations *set_expand_repetitions 18 *symmetry_elements all_existing *expand_elements all_existing

72 68 Description of the New Functionalities MSC.Marc Mentat Postprocessing Enhancements To enable its use, select the POST PROCEDURE button. See the figures below of the original analysis on the left, and the full 3-D model is on the right. C. Merge Contact Model Files A new command *post_merge_bbc has been added that automatically merges the formatted MSC.Marc Mentat model file containing the beam-to-beam contact location points for the current increment with the current postprocessing model, if that file exists. Similarly, the new command *post_merge_spline automatically merges the formatted model file containing the analytical description of deformable contact bodies for a given increment with the current postprocessing model, if that file exists. These files are created by MSC.Marc during a contact analysis if the appropriate flags have been switched on during preprocessing. The flags can be found in the JOB RESULTS CONTACT MODEL FILES menu and the new commands can be found in the POST PROCESSING RESULTS TOOLS menu. Both commands can be used in combination with the new *post_procedure_file facility (see item 2, above) to automatically merge the appropriate model file when an increment is read from the post file. Note that in such a procedure file, the *clear_geometry command should be called prior to one of these commands to remove any points, curves, and surfaces that were merged for a previous increment. D. Generalized XY-Plot Several enhancements have been made to the XY-plotter. The legend of the plot is now switched on by default. The names of the curves, as displayed in the legend, are by default derived from the legend and the names of the x- and y-axes of the original plot from which they were copied. New commands have been added to change the curve name (*set_xy_plot_curve_name) and to set the title of the plot (*set_xy_plot_title) and the names of the x- and y-axes (*set_xy_plot_xname and *set_xy_plot_yname, respectively). Finally, the XY-plotter now draws multiple curves using the same colors and symbol sequence as the history and path plots.