autodyn release 12.0 what’s new?s2.bitdownload.ir/engineering/all.ansys/ansys 12...

AUTODYN® Release 12.0 What’s New?

ANSYS, Inc. Release 12.0 Southpointe April 2009 275 Technology Drive Canonsburg, PA 15317 ANSYS, Inc. is [email protected] certified to ISO http://www.ansys.com 9001:2008. (T) 724-746-3304 (F) 724-514-9494

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AUTODYN® version 12.0, What’s New?

ii Release 12.0 - © 2009 SAS IP, Inc. All rights reserved. – Contains proprietary and confidential information of ANSYS, Inc and its subsidiaries and affiliates.

Published: 2009-04-17

Copyright and Trademark Information © 2009 SAS IP, Inc. All rights reserved. Unauthorized use, distribution or duplication is prohibited. ANSYS, ANSYS Workbench, AUTODYN, CFX, FLUENT and any and all ANSYS, Inc. brand, product, service and feature names, logos and slogans are registered trademarks or trademarks of ANSYS, Inc. or its subsidiaries located in the United States or other countries. ICEM CFD is a trademark used by ANSYS, Inc. under license. All other brand, product, service and feature names or trademarks are the property of their respective owners. Disclaimer Notice THIS ANSYS SOFTWARE PRODUCT AND PROGRAM DOCUMENTATION INCLUDE TRADE SECRETS AND ARE CONFIDENTIAL AND PROPRIETARY PRODUCTS OF ANSYS, INC., ITS SUBSIDIARIES, OR LICENSORS. The software products and documentation are furnished by ANSYS, Inc., its subsidiaries, or affiliates under a software license agreement that contains provisions concerning non-disclosure, copying, length and nature of use, compliance with exporting laws, warranties, disclaimers, limitations of liability, and remedies, and other provisions. The software products and documentation may be used, disclosed, transferred, or copied only in accordance with the terms and conditions of that software license agreement. ANSYS, Inc. is certified to ISO 9001:2008 . U.S. Government Rights For U.S. Government users, except as specifically granted by the ANSYS, Inc. software license agreement, the use, duplication, or disclosure by the United States Government is subject to restrictions stated in the ANSYS, Inc. software license agreement and FAR 12.212 (for non DOD licenses). Third-Party Software See the legal information in the product help files for the complete Legal Notice for ANSYS proprietary software and third-party software. If you are unable to access the Legal Notice, please contact ANSYS, Inc. Published in the U.S.A.


Release 12.0 - © 2009 SAS IP, Inc. All rights reserved. – Contains proprietary and confidential information iii of ANSYS, Inc and its subsidiaries and affiliates.


TABLE OF CONTENTS 1. Introduction ............................................................................................... 1 2. AUTODYN and ANSYS Workbench ......................................................... 1

2.1. AUTODYN in ANSYS Workbench ..................................................... 1 2.2. ANSYS Workbench GUI .................................................................... 1 2.3. Systems ............................................................................................. 3 2.4. System Linking .................................................................................. 6 2.5. Project File Management ................................................................... 8 2.6. Legacy Databases ........................................................................... 10 2.7. Version 12.0 Licensing .................................................................... 10

2.7.1. Single License Sharing ............................................................. 11 2.7.2. Licensing Pause ....................................................................... 12

3. Solver Enhancements ............................................................................. 14 3.1. Trajectory Contact ........................................................................... 14

3.1.1. Decomposition Response(DCR) and Penalty method .............. 16 3.1.2. Self-Interaction ......................................................................... 17 3.1.3. Friction ...................................................................................... 18

3.2. Breakable bonded Connections ....................................................... 19 3.2.1. How to generate bonded contact .............................................. 20

3.3. Discrete reinforcement ..................................................................... 21 3.3.1. How to generate discrete reinforcement ................................... 22

3.4. Breakable spot welds....................................................................... 23 3.5. Merging of unstructured joined nodes.............................................. 24 3.6. Support of local coordinate systems ................................................ 25

3.6.1. Boundary conditions ................................................................. 25 3.6.2. Material directions .................................................................... 26

3.7. 2D Unstructured Elements ............................................................... 27 3.7.1. 2D Unstructured Interaction ...................................................... 28

3.8. New global erosion option ............................................................... 31 3.9. Coupling for 3d multi-material Euler joined meshes ........................ 31 3.10. Dezoning for 3D coupled Euler meshes ....................................... 32 3.11. Using implicit ANSYS results for initialization (implicit to explicit) 33 3.12. 64-bit Windows Support ............................................................... 36

4. Material Modeling Enhancements ........................................................... 37 4.1. Hyperelastic material model enhancement ...................................... 37

4.1.1. Polynomial Strain Energy Function ........................................... 37 4.1.2. Material Data Input ................................................................... 37

4.2. Plastic hardening model enhancements .......................................... 38 4.2.1. Isotropic Hardening .................................................................. 38 4.2.2. Kinematic Hardening ................................................................ 39

4.3. Orthotropic material enhancements ................................................. 41 4.3.1. Material direction definition in local axis system ....................... 41 4.3.2. New user subroutine for the definition of material directions .... 42 4.3.3. Improved material axis direction calculation ............................. 42 4.3.4. Enhanced checks on orthotropic yield strength definition ......... 42

4.4. Material erosion enhancements ....................................................... 43 4.5. Multi-body rigid material with failure ................................................ 43

5. Post-processing ...................................................................................... 45


iv Release 12.0 - © 2009 SAS IP, Inc. All rights reserved. – Contains proprietary and confidential information of ANSYS, Inc and its subsidiaries and affiliates.


5.1. Directional plastic strain output ........................................................ 45 5.2. New model rotation .......................................................................... 45

6. User subroutines ..................................................................................... 46 7. Supported Operating Systems and Compilers ........................................ 47 8. Installation ............................................................................................... 48

8.1. Windows .......................................................................................... 48 8.2. Linux Installation .............................................................................. 50


Release 12.0 - © 2009 SAS IP, Inc. All rights reserved. – Contains proprietary and confidential information 1 of ANSYS, Inc and its subsidiaries and affiliates.


1. INTRODUCTION AUTODYN release 12.0 is released within the next generation ANSYS Workbench framework. The next generation ANSYS Workbench brings many new possibilities to the AUTODYN user in terms of CAD geometry import, complex geometry generation, meshing and ease of use. To complement the significantly enhanced model generation capabilities, a range of new solver, material modeling and post-processing features enable larger simulations to be solved in a faster time. 2. AUTODYN AND ANSYS WORKBENCH 2.1. AUTODYN IN ANSYS WORKBENCH An overview of how to access AUTODYN in Workbench at release 12 is provided below. Full guidance on how to use Workbench at release 12 is provided in the on-line help system of Workbench. 2.2. ANSYS WORKBENCH GUI A new paradigm for managing simulations is used with the ANSYS Workbench GUI at release 12. The ANSYS Workbench GUI now consists primarily of a Toolbox region, Project Schematic, Toolbar, and Menu bar. Depending on the analysis type and/or application or workspace, you may also see other windows, tables, charts, etc.


2 Release 12.0 - © 2009 SAS IP, Inc. All rights reserved. – Contains proprietary and confidential information of ANSYS, Inc and its subsidiaries and affiliates.


One way to work in ANSYS Workbench is to drag an item such as a component or analysis system from the Toolbox to the Project Schematic or to double-click on an item to initiate the default action. You can also use the context menus, accessible from a right-mouse click, for additional options. You will view your analysis systems -- the components that make up your analysis -- in the Project Schematic, including all connections and links between the systems. The individual applications in which you work will display separately from the ANSYS Workbench GUI, but the results of the actions you take in the applications may be reflected in the Project Schematic. Full details of how to use ANSYS Workbench are provided in “Workbench Help” section of the Workbench on-line help system.




2.3. SYSTEMS An ANSYS AUTODYN product license should enable three primary systems in the Toolbox of the Workbench GUI.

AUTODYN System The AUTODYN system is located in the “Component Systems” toolbox of the Workbench GUI. This system allows you to start-up the traditional ANSYS AUTODYN application and includes pre-processing, solve and post-processing options for all AUTODYN solvers. To start-up the AUTODYN application simply insert an AUTODYN system into the project schematic. Then double click the Setup cell.

The AUTODYN application will start-up and you can setup, solve, post-process models in the familiar AUTODYN user interface. The default start up mode will be the generation of a new model. The start up mode can be changed by right-mouse click the Setup cell after which you can select:

• New Model - default • Import Model - open existing

AUTODYN Save file • Select user executable - defines

where a user customized version of AUTODYN resides

• Duplicate - makes a copy of the model file

• Transfer Data From - Model data from either the Mesh system or the Explicit Dynamics system are imported into AUTODYN

After selection of the desired Setup cell setting double clicking the Setup cell again will start up AUTODYN in the required mode.




Notes: • Model Name: The database for an AUTODYN model will now

always be admodel_0.ad. The project name is now the unique identifier for all databases (see below).

• 2D/3D symmetry: By default, the AUTODYN application assumes you are performing a 3D simulation in the default unit set (mm, mg, and ms). To define 2D axial or planar symmetry, use the Setup, Symmetry option in the toolbar after start-up of the AUTODYN application.

Saving a project: To save a model, the recommended approach is to save the Workbench project either from within the AUTODYN application (File, Save Project) or from the project page of Workbench. This ensures all data used in the AUTODYN simulation is saved to disk.

• Exporting an AUTODYN database: The AUTODYN database (restart file) can be exported to a file (independent of the Workbench project) using the File, Export options in the AUTODYN application.

Please refer to the “Component Systems, AUTODYN” section of the Workbench On-line help for further details on the operations and properties available for an AUTODYN system.

Explicit Dynamics (ANSYS) system

The Explicit Dynamics (ANSYS) system is located in the “Analysis Systems” toolbox of the Workbench GUI. This system allows you to completely set up, solve and post-process an explicit dynamics simulation with the ANSYS Mechanical Workbench user environment. At release 12, this user interface fully supports the 3D Finite Element




features of ANSYS AUTODYN (unstructured Lagrange solvers, isotropic inert materials and linear orthotropic materials). The system contains a number of unique features for explicit dynamic simulation inside Workbench:

• Unidirectional and bidirectional links to CAD geometry • Links to DesignModeler • Advanced meshing capabilities tailored for explicit analysis • Mesh independent loading and boundary conditions • Fully parameterized engineering data, geometry, initial

conditions, loads, boundary conditions • Automated “What If” analysis capability • Links to design exploration tools

The full capabilities of the ANSYS Explicit Dynamics system are described in the on-line help for the Mechanical analysis systems in Workbench. Models setup in the ANSYS Explicit Dynamics system can be persistently linked to an AUTODYN system to transfer material data, mesh, connections, loads and constraints, analysis settings etc… into ANSYS AUTODYN. For modelling complex geometries in ANSYS AUTODYN, we recommend you define the FE components of the model in an ANSYS Explicit Dynamics system then transfer the model setup to the AUTODYN system and add on your Euler/SPH regions and explicit FSI/Coupling as required.

Mesh system The Mesh system is located in the “Component Systems” toolbox of the Workbench GUI. This system allows you to link to your model geometry and generate a mesh. The mesh can then be transferred to an AUTODYN system for subsequent analysis. This system allows you to use a similar workflow that was available at release 11 to link AUTODYN models to CAD/geometry and meshing tools. However with Version 12 the link is not persistent anymore, which means that with every update of the workflow system the definitions made in AUTODYN (material filling, boundary condition assignment, etc.) are lost and have to be re-applied. Therefore at release 12, we recommend using the ANSYS Explicit Dynamics system to link to CAD/geometry and generate a mesh for use in AUTODYN, where loads, constraints and material assignments are maintained after any change to the geometry or mesh.




2.4. SYSTEM LINKING If the mesh/geometry of the application to be solved in AUTODYN cannot be made with the simple model building tools available in the AUTODYN application, we recommend the following approaches to build the AUTODYN model.

ANSYS Explicit Dynamics => AUTODYN

The recommended approach for bringing Lagrangian FE based models with complex geometries into AUTODYN is to start off with an ANSYS Explicit Dynamics system.

• Define material data using the Engineering Data application • Link directly to CAD Geometry or use DesignModeler to generate

geometry directly or adapt CAD geometry for simulation purposes • Mesh the geometry and define connections (Contact, Joins,

Spotwelds) Optionally: • Assign initial velocities to components • Apply loads and constraints directly to the geometry • Define solution controls and outputs • Solve and Post process results

To transfer the model from an ANSYS Explicit Dynamics system to the AUTODYN application, link the Setup cell of the ANSYS Explicit Dynamics system to the Setup cell of the AUTODYN system. Open the AUTODYN application by double click on the AUTODYN system Setup cell. All relevant model information defined in Engineering Data, Geometry, Model and Setup components of an ANSYS Explicit Dynamics system are transferred into the AUTODYN application. Once in the AUTODYN application, you can complete the model setup (for example add Euler and SPH regions) then solve in the AUTODYN application.




The link generated between the AUTODYN and ANSYS Explicit Dynamics system is persistent. You can make changes to the model defined in the ANSYS Explicit Dynamics system, update the ANSYS Explicit Dynamics system Setup cell, then update the AUTODYN system Setup cell. The latest model definition will be transferred into the AUTODYN model while retaining additional features present only in the AUTODYN application. This makes it very easy to make changes to model. Notes:

• Changes made to the model in the AUTODYN application are NOT transferred back to the ANSYS Explicit Dynamics system. The link is one way.

• To avoid overwriting changes you make in the AUTODYN application, we recommend that if a portion of the model is defined in the ANSYS Explicit Dynamics system (for example and initial velocity) then only make changes to this in the ANSYS Explicit Dynamics system. Transfer to the AUTODYN model using the update procedure described above.

• Local co-ordinate systems defined and used in the ANSYS Explicit Dynamics system are transferred through to the AUTODYN application however they cannot be reviewed or modified in AUTODYN.

• Displacement boundary conditions defined in the ANSYS Explicit Dynamics system are converted to equivalent velocity boundary conditions in the AUTODYN application.

• Loading defined in tabular form in the ANSYS Explicit Dynamics system cannot be edited or reviewed in the AUTODYN application. The data is transferred and used in the AUTODYN simulation.

• Spot weld breaking criteria defined in the ANSYS Explicit Dynamics system will be converted from a stress to a force criterion in the AUTODYN application.

Meshing => AUTODYN If you only want to transfer a Mesh (of complex geometry) into AUTODYN then this can be achieved (as in release 11.0) using a Mesh system. Start by inserting a Mesh system from the Components toolbox.

• Link directly to CAD Geometry or use DesignModeler to generate geometry directly or adapt CAD geometry for simulation purposes




• Mesh the geometry • Create Named Selections

To transfer a mesh from the Mesh to the AUTODYN application, link the Mesh cell of the Mesh system to the Setup cell of the AUTODYN system. Open the AUTODYN application by double clicking on the AUTODYN system Setup cell. The mesh and Named selections will be transferred to AUTODYN. With Version 12 the link generated between the AUTODYN and Mesh system is not persistent anymore. This means that with every update of the workflow system the definitions made in AUTODYN (material filling, boundary condition assignment, etc.) are lost and have to be re-applied. Therefore at release 12, we recommend using the ANSYS Explicit Dynamics system to link to CAD/geometry and generate a mesh for use in AUTODYN, where loads, constraints and material assignments are maintained after any change to the geometry or mesh. Notes:

• Connections defined in the Mesh system will not be transferred to the AUTODYN application.

• Material assignments, Boundary Conditions and Loads defined in the AUTODYN application will be lost during the update and will have to be re-applied.

FEModeler Legacy and third party FE model data can be imported into the FEModeler system in Component toolbox. This data can be transferred into AUTODYN via a Mesh system or an ANSYS Explicit Dynamics system. Note: Direct transfer of data from the FEModeler application into AUTODYN is not possible at release 12. 2.5. PROJECT FILE MANAGEMENT At release 12 of Workbench, the ANSYS Workbench file management system is utilized to keep all AUTODYN and related database files. ANSYS Workbench’s file management system keeps multiple databases under a single project. Workbench creates a project folder as the top level folder for each project, at the same level as the project file. The project folder will be named <filename>_files, where <filename> is a name you provide. The project file will be named <filename>.wbpj. Under the project folder is a design point subdirectory for each design point in the project. The active design point is always design point 0 (DP0) and




corresponds to the design point labeled Current in the ANSYS Workbench GUI. At release 12, AUTODYN system files will always be located in the DP0 folder. Under each design point folder are system folders for each system type in the project (i.e., Mechanical, FLUENT, etc.). Each system folder contains solver-specific files and folders, such as input files, model directories, engineering data, resources, etc. System folders for each system type are named as follows: System Type Folder name AUTODYN ATD BladeGen BG Design Exploration DX Engineering Data ENGD Finite Element Modeler FEM Fluid Dynamics (FLUENT) FFF Fluid Dynamics (CFX) CFX Fluid Dynamics (Turbo) TFF Geometry Geom Mesh SYS Mechanical SYS Mechanical APDL APDL TurboGrid TS Vista TF VTF In addition to the system folders, the dpn folders also contain a global folder. This folder contains subdirectories for all systems in the project. These subdirectories contain all database files, as well as any files that are associated directly with the database files. For example, the Mechanical application will write figures and images and contact tool data to the appropriate system subdirectory under the global folder. A project directory that includes an AUTODYN system linked to an ANSYS Explicit Dynamics system might look like this: Myworkbenchproject.wbpj DP0 ATD admodel_adres global MECH SYS SYS DM




ENGD MECH user_files Also under the project folder is a user_files directory. This folder contains any files (such as input files, referenced files, etc.) that you supply to a project. You are responsible for placing required files into this directory; however, ANSYS Workbench will protect this directory and ensure that it is managed and archived appropriately with the rest of the project. We strongly recommend that you do not directly modify any of the content in any of the ANSYS Workbench project directories or subdirectories. Always work through the ANSYS Workbench GUI to manage your project. ANSYS Workbench will not recognize or be aware of any changes that you make directly in the file system (such as adding or removing a file). Importing Files When working in ANSYS Workbench, you may need to import files, such as input files, existing mesh files, geometries, etc. When you edit an imported file, ANSYS Workbench saves a copy of the file to the project directory, rather than overwriting the original file. This process ensures that your original files are never compromised. Most files from previous releases can be imported using File> Import. The import operation will create systems, cells, and links to represent the previous release project. 2.6. LEGACY DATABASES Version 11.0 Workbench databases or AUTODYN cycle zero files can be imported into the release 12 project using the Workbench File> Import option. This operation will result in a copy of the release 11 database being made in the current project. The AUTODYN system will be created, along with associated geometry and meshing systems (if they exist). Note that the links between an AUTODYN system and a Meshing or FEModeler system will not be generated in the release 12 project. In release 12 we are using a new method for linking systems which is incompatible with previous versions. You may manually re-link the systems in release 12 however we cannot guarantee that updates in the meshing or FEModeler systems will correctly transfer to the AUTODYN system. Please check results carefully.

2.7. VERSION 12.0 LICENSING The 12.0 License Manager is required to run ANSYS 12.0 products. The ANSYS, Inc. License Manager and its associated processes have changed




significantly at Version 12.0. Please carefully review the ANSYS, Inc. Licensing Guide for more information on these changes. The new Version 12.0 licensing process will continue to support ANSYS Workbench and AUTODYN licensing from prior releases. The licensing installation process is now separate for the server and the client. The client portion is installed automatically during a product installation and requires no further action. The server portion is a separate installation and must be installed for your ANSYS, Inc. products to run. With AUTODYN Version 12.0 no distinction is made anymore between a 2D or a 3D AUTODYN solver license. A single AUTODYN solver license will allow you to run one instance of an AUTODYN system or ANSYS Explicit Dynamics system or Meshing system.

ANSYS Workbench offers two licensing methods at Release 12.0:

• Share a single solver license between applications (default) (shared mode)

• Use a separate solver license for each application (separate mode) 2.7.1. Single License Sharing ANSYS Workbench allows you to work across multiple applications in ANSYS Workbench while consuming only one solver license per user per session. Using concurrent licensing, the active application holds the license, preventing other applications that are sharing that license from using it during that time. The application requiring use of the license is called a concurrency event. For example, setting up and running an ANSYS Explicit Dynamics analysis and running an AUTODYN analysis would each be a concurrency event. The application holding the license must close, or receive an automatic release request to release the license and allow another application to use it. Licenses cannot be released while an application is actively performing a licensed operation (for example, an application cannot release a license in the




middle of a solve operation; the license cannot be released until the solve operation is completed). However, ANSYS AUTODYN offers a s Pause option to release its license temporarily and allow another application to use it (see next section). Because the shared mode is the default, you do not have to take any action to run this way. You can change the licensing preference from shared mode to separate mode (separate solver license for each application) by using Start, All Programs, ANSYS 12.0, ANSYS Client Licensing, User License Preferences or to select in Workbench Tools, License Preference. In both cases the same user license preference window pops-up where you can change the preference. For more information please see also the ANSYS,Inc Licensing Guide.

2.7.2. Licensing Pause If you are working with a project which contains an AUTODYN system linked to an ANSYS Explicit Dynamics system you will not be able to open and work in both applications simultaneously in shared licensing mode or when the license server only has one solver license available. For example, if you want to generate a new mesh in the meshing application then you will need to close the AUTODYN application to release the license for the meshing application to use.




As an alternative to closing the AUTODYN application we have implemented a mechanism by which the user can leave the AUTODYN application open, but release the license for another application to use. While the license is released, the AUTODYN user interface will be locked. Note that the Pause option is not available during an AUTODYN analysis run. To pause the license, in the AUTODYN application select:

After selection of the Pause option the license is released, and the AUTODYN user interface will be locked. To continue the AUTODYN application the user can select Retry to try to obtain the license again. The Close App option will exit the AUTODYN application without saving any data.




3. SOLVER ENHANCEMENTS 3.1. TRAJECTORY CONTACT The Trajectory contact algorithm, available for all 3D unstructured volume elements (hexahedral. tetrahedral, wedge), shells (quad and tri), beams, rigid bodies, has been significantly refined and enhanced and is now considered to be general release. Trajectory contact involving SPH parts currently still has Beta status and therefore may not be as stable or robust as expected in a general release version. Also we would request that you inform ANSYS if you experience any problems in using this Beta feature so that we may correct any issues as timely as possible. The Trajectory contact in AUTODYN Version 12.0 now offers enhancements in the area of:

• New penalty contact algorithm • Shell thickness in the contact • Initial penetration check and correction • Static and dynamic friction.




The sub-options available for trajectory contact are: Method None – deactivates contact

Penalty – A penalty force will be applied to a contacting node to push it back to the contacted face. Decomposition Response – A contacting node is pushed back to the contacting face conserving momentum and energy

Shell thickness factor The value of the factor has to be taken between 0.0 and 1.0 and determines the amount of the shell thickness that is taken into account as the interaction distance. A factor of 1.0 takes the full shell thickness into account, which means that the contact surface is positioned at half the shell thickness on both sides of the shell mid plane. A factor of 0.0 means that the shell has no contact thickness and the contact surface is positioned at the shell mid plane. Note that for shell node on shell face impacts, the node is always located at the mid-surface of the shell.

Initial penetrations - Check On clicking this button, AUTODYN will search the model for initial penetrations of nodes into surfaces. If any penetrating nodes/surfaces are found, a new Group will be created so that they can be identified/displayed using the Groups panel. Nodes that initially penetrate surfaces will be “missed” by the contact algorithm.

Initial penetrations - Fix When this option is selected the initially penetrated nodes are set back to the closest contact surface and no initial penetrations are present at the start of the analysis. This option is meant for situations where small initial penetrations occur (for example because of round-off) and should be used with care because the analysis model geometry is changed. Note that it may not be possible to remove all initial penetrations with this algorithm. Features are available in the DesignModeler and Meshing application to prevent initial penetrations occurring.




Initial penetrations - Undo This option will restore the geometry of the analysis model before the initial penetrations were fixed. It is recommended that the fixed initial penetrations are checked before the model is modified further otherwise it may not possible to undo the last fix operation.

Retain inertia of eroded nodes

Select this toggle to retain inertia of nodes freed from elements during erosion.

Interaction by Part Select interaction on Part by Part basis (as done with Gap contact).

Self-interaction of parts Set this toggle to activate self contact for volume elements.

Self-interaction tolerance

Percentage of the element characteristic dimension used as the trigger for element erosion. Values can range from very small (most accurate) to 0.5 (maximum allowed). Default value is 0.2. This is equivalent to defining a gap size, but is only used for self-interaction erosion purposes.

3.1.1. Decomposition Response(DCR) and Penalty method The trajectory of nodes and faces included in frictional or frictionless contact are tracked during the computation cycle. If the trajectory of a node and a face intersects during the cycle a contact event is detected.

If a contact event is detected the node involved in the contact will be pushed back towards the true contact position during the computational cycle. There are two methods available:




1. Penalty. If a contact event is detected, a local penalty force is calculated to push the node back to the face. Equal and opposite forces are calculated on the nodes of the face in order to conserve linear and angular momentum. The applied penalty force will push the node back towards the true contact position during the cycle. However, it will take several cycles to satisfy the contact condition. Kinetic energy is not necessarily conserved. The conservation of energy can be tracked using the energy time history.

2. Decomposition Response (DCR).

All contacts that take place at the same point in time are first detected. The response of the system to these contact events is then calculated to conserve momentum and energy. During this process, forces are calculated to ensure that the resulting position of the nodes and faces does not result in further penetration at that point in time. The decomposition response algorithm is more impulsive (in a given computational cycle) than the penalty method. This can give rise to large hourglass energies and energy errors.

3.1.2. Self-Interaction By default the contact detection algorithm will only check for external nodes of a part contacting with external faces of other parts. If the self-interaction option is switched on the contact detection algorithm will also check for external nodes of a part contacting with faces of the same part in addition to other parts. This is the most robust contact setting since all possible external contacts should be detected.

The self-interaction option enables automatic erosion when an element deforms such that one of its nodes comes within a specified distance of one of its faces. This option will prevent that elements become degenerated. The specified distance is calculated using the Self-interaction Tol. value which is a factor in the range 0.1 to 0.5. This factor is multiplied by the smallest characteristic dimension of the elements in the mesh to give a physical dimension.




3.1.3. Friction Trajectory contact can be used with static and dynamic friction between different parts, which is available under Interaction by Part. Friction is not available for Interaction definition by Group.

A non-zero value for the Static Friction coefficient will activate Coulomb type friction between bodies (F=µR). A non-zero value for the Dynamic Friction coefficient and the Dynamic friction decay constant will activate the use of dynamic friction where an effective friction coefficient, µ, is used which is given by:

vdsd e βµµµµ −−+= )(

where

µs = static coefficient of friction µd = dynamic coefficient of friction β = exponential decay coefficient v = relative sliding velocity at point of contact.

Element will be erode




Aside from the friction definition described above there is also a user defined friction option available through the use of a new user-subroutine called EXFRICTION for 3D analysis or EXFRICTION2D for 2D analysis.

Current Limitations:

• The trajectory contact option cannot currently be used in parallel simulations.

• The Trajectory contact option cannot be used in combination with joined unstructured parts. However, a new option is available that merges all joined unstructured nodes.

• Interaction of SPH nodes is considered Beta status and accounting for their full natural thickness/size is currently not available.

• The decomposition response algorithm cannot currently be used in combination with bonded contact regions. The formulation will automatically switch to the Penalty method if bonded regions are present in the model.

3.2. BREAKABLE BONDED CONNECTIONS Bonded contact allows the nodes of an unstructured Part to be bonded to a face of another unstructured Part. Bonded contact alleviates the requirement that for joining purposes two nodes need to reside at the same physical location. The nodes that are to be bonded to a face may have an offset with respect to the face and the offset is a user-defined maximum physical normal distance of a node from a face which can be bonded together. During the analysis the nodes are kept at the same relative position on the face to which they are bonded. Bonds are allowed to fail and break upon a user-defined criterion:

• Normal stress limit: maximum normal stress that can be sustained at the bond




• Shear stress limit: maximum shear stress that can be sustained at the bond

Failure of the bond occurs when:

1expexp

≥

+

s

s

sn

n

n

SSσσ

where σn and σs are normal and shear stress at the bond, Sn and Ss are the maximum allowed normal and shear stress limits and expn and exps are user defined exponential coefficients. The normal stress at the bond σn is nonzero for tensile values only.

3.2.1. How to generate bonded contact Bonded joins can be generated in AUTODYN on a part basis as well as on a (multiple) face group basis. The bonds can be defined by using the option Setup, Joins, Bonded Face Connections and

o Create a new Bond o Enter the bond properties o Assign face groups/parts to the bond

Can be single or multiple groups




Bonded Connections can also be defined in an ANSYS Explicit Dynamics system and automatically transferred into a linked AUTODYN system. Notes

1) The automatic search algorithm for bonded regions will bond a node to the first face found within the specified offset distance. To ensure nodes are bonded to the nearest face, the value of the offset distance should be defined to be as small as possible.

2) The element variable BOND_STATUS is used to record how many nodes are actively bonded to the faces of an element. This variable can be contoured to verify that bonds are correctly defined. If a bond fails during the simulation the bond status will show a reduction in the number of active bonds. When an element has no remaining bonds the value of BOND_STATUS is set to -1.0.

3) Bonded contact is only available with the Penalty algorithm for trajectory contact.

4) Bonded contact is currently only available for volume and shell elements.

5) When bonded contact is used in an implicit-explicit initialization analysis it is advised to use the double precision version of AUTODYN. The implicit analysis in ANSYS Mechanical is performed in double precision and to assure that the model used in AUTODYN is exactly the same as the one used in ANSYS Mechanical running double precision is required to avoid possible round-off errors.

3.3. DISCRETE REINFORCEMENT This new option allows reinforcing bars, modelled with beam elements to be tied (bonded) to the volume of a solid element, without the restriction that the nodes of the beams and volume elements initially need to reside at the same physical location. The bonded beam nodes are constrained to stay at the same initial parametric location within the volume element during element deformation. Typical applications involve reinforced concrete or reinforced rubber structures like tires and hoses. At start-up, AUTODYN will determine the parametric positions of all nodes of beam Parts, selected as reinforcement (Parts, Solver), within volume elements (hex, tet, penta) in the model. The nodes are tied to the parametric co-ordinate of the volume element until the element erodes. On erosion of the volume element, the beam node bonding constraint is removed and becomes a free beam node. On erosion of a beam element node, if inertia is retained, the node will remain tied to the parametric location of the volume element. If inertia is not retained, the node will be eroded.




Volume elements that are intersected by reinforcement beams, but do not contain a beam node, will not be experiencing any reinforced beam forces. Good modeling practice is therefore to have the element size of the beams similar or less than that of the volume elements.

Limitations

• The reinforcing option is only available for unstructured beam and volume elements and is not supported for IJK Parts.

• Currently models with discrete reinforcement cannot be run in parallel. 3.3.1. How to generate discrete reinforcement Discrete reinforcement can automatically be generated by using the Volume element reinforcement option for 3D beam Parts, under Solver settings.




Multiple beam parts can be selected as reinforcement using the Body Interaction object in the connections folder in the ANSYS Explicit Dynamics system.

3.4. BREAKABLE SPOT WELDS

Spot welds generated in an ANSYS Explicit Dynamics systems are transferred to the AUTODYN system as beam elements filled with a rigid material. Spot welds utilise the multi-body rigid material option where each spot weld acts as an individual rigid body. Spot welds can be defined as breakable by force:

Normal force limit: maximum normal force that can be sustained by the weld

Shear force limit: maximum shear force that can be sustained by the weld.

Failure of the spot weld occurs when:

1expexp

≥

+

s

s

sn

n

n

Sf

Sf

where fn and fs are normal and shear interface forces, Sn and Ss are the maximum allowed normal and shear force limits and expn and exps are user defined exponential coefficients. The normal interface force fn is nonzero for tensile values only. Note that spot welds cannot be generated directly inside an AUTODYN system. Spot welds should be defined in an ANSYS Explicit Dynamics system and automatically transferred to a linked AUTODYN system. For spot weld connections between shells a single beam rigid body is used for each spot weld.




For spot weld connections between volume bodies a multiple beam rigid body is automatically generated for each spot weld in the ANSYS Explicit Dynamics system in order to guarantee the transfer of bending over the spot weld.

After failure of the spot weld the spot weld rigid body will be removed from the analysis model as can be seen above. Within an ANSYS Explicit Dynamics system an effective area can be input for spot welds, thus the breakable criteria can be defined in terms of stress. This stress is converted to force when transferred into AUTODYN. Spot welds of zero length are permitted. However, if such spot welds are defined as breakable the above failure is modified since local normal and shear directions cannot be defined. A modified criterion using global forces is used instead:

0.1)/()( 22222 <+++ snzyx ssdfdfdf where dfx, dfy and dfz are the global force differences across the spotweld. Notes:

1) A spotweld is equivalent to a rigid body and as such multiple nodal boundary conditions cannot be applied to spot welds.

2) Currently analysis models containing spotwelds cannot be run in parallel.

3.5. MERGING OF UNSTRUCTURED JOINED NODES. A new option to merge joined unstructured nodes has been implemented to increase robustness in many applications involving joins.




Since trajectory contact does not allow the use of joined unstructured nodes in the contact, the new merge option can be used to remove joins from the model. Bonded connections are recommended over node to node joins for unstructured models. The option of merging joined unstructured nodes will merge the (multiple) joined nodes that reside at the same physical location in the model into one single unstructured node. The option is available under the Join menu. 3.6. SUPPORT OF LOCAL COORDINATE SYSTEMS AUTODYN now supports the capability of using local co-ordinate systems in ANSYS Explicit Dynamics to define boundary conditions and initial material directions for volume elements filled with linear orthotropic materials. The generation or display of local axis in AUTODYN itself is not supported. The use and display of local axis is only available during the setup of a model in an ANSYS Explicit Dynamics system. 3.6.1. Boundary conditions To define boundary conditions in a local coordinate system a local coordinate system needs to be defined first. During the boundary condition definition the coordinate system, global or local, has to be selected by the user.




This local co-ordinate system is then automatically used to initialise the boundary condition during model initialisation in AUTODYN and used during the analysis. Boundary conditions defined in a local coordinate system in ANSYS Explicit Dynamics can be modified inside AUTODYN, Below a typical example is shown of the impact of a metal rod on a slanted rigid wall, using a local coordinate system defined in ANSYS Explicit Dynamics and a Velocity Limit boundary in AUTODYN

3.6.2. Material directions To define orthotropic material directions in a local co-ordinate system, a local co-ordinate system needs to be assigned to a body when setting up a model in an ANSYS Explicit Dynamics system in Workbench. This local co-ordinate system is then automatically used to initialise the material directions during model initialisation in AUTODYN. For more information about orthotropic material direction definition see section 4.3.1.




3.7. 2D UNSTRUCTURED ELEMENTS A new generation of 2D mesh based Lagrangian volume solvers is now available in AUTODYN. A new quadrilateral and triangular volume solver are available. This feature currently has Beta status and therefore may not be as stable or robust as expected in a general release version. Also we would request that you inform ANSYS if you experience any problems in using this Beta feature so that we may correct any issues as timely as possible. Unstructured quadrilateral or triangular volume parts cannot be generated in AUTODYN itself, but can be generated within an ANSYS Explicit Dynamics or Meshing system and automatically imported into a linked AUTODYN system. Note that an ANSYS Explicit Dynamics system cannot perform a 2D analysis. Before you can set up a 2D analysis model the beta option needs to be activated in the Work bench GUI. On the toolbar of the Workbench GUI you need to select Tools>Options>Appearance and scroll down to select Beta Options.

To setup a 2D analysis model in Workbench the Analysis Type needs to be set to 2D. By default the Analysis Type is set to 3D in Workbench and to set the Analysis Type to 2D you need to right click the Geometry cell of the ANSYS Explicit or Mesh system and select Properties and change the Analysis type from 3D to 2D.




The new 2D unstructured solvers cannot be used in combination with the existing IJK structured Lagrangian solvers (volume, shell or SPH) when contact or coupling is used in an analysis model. One exception is the use of unstructured parts for filling operations into structured Eulerian parts. Pre- and post- processing options are available in the AUTODYN interface to allow setup and post-processing of 2D unstructured models in a similar manner as is available for 3D unstructured models. 3.7.1. 2D Unstructured Interaction The new 2D unstructured solvers can be used in combination with Lagrange/Lagrange Interactions and Euler/Lagrange interactions with the structured multi-material and ideal gas Euler solvers. Erosion can be used in all cases. For contact of 2D unstructured volume parts the new 2D trajectory contact has to be used which provides similar functionality to the 3D Trajectory contact algorithm described in section 3.1. For 2D analyses the Initial Penetration Check and Fix options are not available. The existing gap contact cannot be used for analysis involving unstructured volume parts and similarly the new 2D trajectory contact option cannot be used for analysis involving structured parts.




Unstructured parts can be coupled to structured Euler multi-material or Euler Ideal Gas parts, where only the automatic (polygon free) coupling option is available.




Notes • The use of reactive materials like the JWL, Lee-Tarver and Powder

Burn material models is not supported for 2D unstructured volume elements.

• The use of rigid materials is not supported for 2D unstructured volume elements.

• Unstructured volume elements cannot be joined.




3.8. NEW GLOBAL EROSION OPTION A new global erosion option has been implemented that can be used to define global erosion criteria for all elements in the model. The global erosion options are only available for 3D unstructured elements. Three erosion criteria have been implemented and can be used in combination in an analysis:

• Global Erosion by Geometric Strain o The user can define a single erosion strain that will be used for

all elements in the model The minimum of the global erosion strain, and the local

material erosion strain (if specified) will be used to check for element erosion

• Global Erosion by Timestep o The user can define a single erosion timestep that will be used

for all elements in the model The maximum of the global and the local material based

erosion timestep (if specified) will be used to check for element erosion

• Global Erosion by Failure o The user can turn on erosion by material failure for all materials.

Using erosion by timestep will activate the element timestep variable which can be used in post-processing 3.9. COUPLING FOR 3D MULTI-MATERIAL EULER JOINED MESHES The 3D Multi-Material Euler solver has been enhanced to allow the use of Euler-Lagrange coupling in combination with multiple joined Eulerian domains. This new capability can reduce the size of the Euler domain required and provides a reduction in model memory size and analysis speedup. This new capability is not available for parallel analysis. Typical example:




3.10. DEZONING FOR 3D COUPLED EULER MESHES In previous versions of AUTODYN the dezoning option for 3D Euler ideal gas and Euler multi-material meshes provided correct results for analysis without coupling to structures. For analysis with coupling to structures the dezoning option often provided inaccurate results, because during dezoning of the Euler mesh the element cover fractions were not correctly taken into account. With Version 12 of AUTODYN the dezoning algorithm for the 3D coupled Euler ideal gas and Euler multi-material solver has been enhanced to take the coverage of the Euler mesh by the coupling surface into account. The dezoning of coupled Euler meshes now also provides correct and accurate results.




3.11. USING IMPLICIT ANSYS RESULTS FOR INITIALIZATION (IMPLICIT

TO EXPLICIT) An AUTODYN explicit analysis can be initialized (or pre-stressed) with the results from either a linear static structural, non-linear static structural or transient dynamic ANSYS Mechanical implicit analysis. Note that this feature requires the ANSYS results to be saved to a .rst file. It is assumed that the same mesh is always used in both the implicit and explicit analyses; otherwise results will not be mapped onto the explicit mesh correctly. Note that higher order quadratic elements may be used in the implicit model. In this case results for the corner nodes and average results for the element will be applied to the explicit mesh. When bonded contact is used in an implicit-explicit initialization analysis it is advised to use the double precision version of AUTODYN. The implicit analysis in ANSYS Mechanical is performed in double precision and to assure that the model used in AUTODYN is exactly the same as the one used in ANSYS Mechanical, running double precision is required to avoid possible round-off errors. In general it is advised to use the double precision of AUTODYN for implicit-explicit initialization analysis, even when bonded contact is not present. The user is advised to check the autodyn.log file shortly after starting the AUTODYN analysis as any errors occurring during the implicit results transfer will be echoed to this file. Two Transfer Type options are available to define what analysis results need to be transferred from the ANSYS implicit analysis to initialize the AUTODYN analysis:

1. Displacement Only Nodal displacements from an ANSYS linear static solution are used to initialize the AUTODYN nodal positions. These displacements are converted to constant nodal velocities and applied for a pre-defined time in order to obtain the required displaced co-ordinates. During this time element stresses/strains are calculated as normal by AUTODYN. Once the displaced nodal positions are achieved all nodal velocities are set to 0 and the solution is completely initialized.

• This option is applicable to unstructured solids (hexahedral and tetrahedral), shells and beams.

• This option is only applicable to results from a linear, static structural analysis.

• Linear elastic materials only can be used in the explicit analysis when using the Displacement Only Option.

• Note that after AUTODYN model initialization static damping (Controls>Damping Options>Static Damping) needs to be applied to change the AUTODYN calculation from a dynamic solution to a state of




stress equilibrium. For optimal convergence, the value chosen for the damping constant, R, may be defined by:

R=2*timestep/T

where timestep is the expected average value of the timestep and T is longest period of vibration for the system being analyzed.

2. Material State Nodal displacements and element stresses, strains, plastic strains and velocities from an ANSYS solution are used to initialize an AUTODYN analysis at cycle 0. The AUTODYN solution is therefore completely initialized at the start of the analysis. • This option is only applicable to unstructured solid elements

(hexahedra and tetrahedral) • This option is applicable to results from a linear static structural,

non-linear static structural or transient dynamic ANSYS Mechanical system.

• The following materials can be used in the AUTODYN solution with the Material State Option:

o Equations of State (linear, hyperelastic). o Strength Models (elastic, von-Mises Johnson-Cook,

piecewise, Zerilli Armstrong, Steinberg Guinan, Cowper Symonds, hyperelastic, and bi-linear and multi-linear isotropic and kinematic hardening).

• Note that static damping can also be applied by using a static damping constant, but this may not be required.

Initialization of an explicit analysis using implicit analysis results can be selected using the option Init. Cond. where the Activate option needs to be selected under Initialize using ANSYS Mechanical results.

The menu shown above is used to configure the transfer of data from the ANSYS Mechanical to the AUTODYN solution and in which manner AUTODYN will be initialized:

• Results File: Select the ANSYS .rst results file to be used to initialize the AUTODYN analysis.




• Transfer Type: Either the Displacement Only or the Material State option.

• Results Time: The result time from the ANSYS Mechanical implicit analysis at which to extract results from the .rst file. For a linear static solution this will always be 1.0. For a nonlinear or transient dynamic solution this time will correspond to a result time from the ANSYS Mechanical analysis.

• Timestep factor: (Note that this option is only applicable for the Displacement Only method.) The initial timestep from the AUTODYN solution is multiplied by the timestep factor. The resulting time (PVELTM) is used together with the nodal displacements from the ANSYS Mechanical analysis to calculate constant nodal velocities. These nodal velocities are applied to the AUTODYN model over PVELTM in order to initialize the AUTODYN nodes to the correct positions.




3.12. 64-BIT WINDOWS SUPPORT 64-bit AUTODYN on Windows works in conjunction with the ANSYS 64-bit Workbench installation to offer full 64-bit support. Compiled specifically for use on Windows 64-bit platforms it takes advantage of larger memory addressing capabilities enabling much larger models (more elements) than is possible on 32-bit platforms. There is no difference between 32-bit and 64-bit AUTODYN in terms of features but it can support larger models when more RAM is also available on the system and additionally can give a small performance increase too.




4. MATERIAL MODELING ENHANCEMENTS 4.1. HYPERELASTIC MATERIAL MODEL ENHANCEMENT A material is said to be hyperelastic if there exists an elastic potential function Ψ (or strain energy function) that is a scalar function of one of the strain or deformation tensors, whose derivative with respect to a strain component determines the corresponding stress component. This can be expressed by:

CS

∂∂

=ψ2

where: S = Second Piola-Kirchhoff stress tensor Ψ = strain energy function C = components of the right Cauchy-Green deformation tensor

Additionally to the several forms of strain energy potential (ψ ) functions AUTODYN already provides for the simulation of nearly incompressible hyperelastic materials a new Polynomial Strain Energy Function has been added. 4.1.1. Polynomial Strain Energy Function The strain energy function of a hyperelastic material can be expanded as an infinite series in terms of the first and second strain invariants I1 and I2. The polynomial form of strain energy function is given below:

( ) ( ) ( ) kN

k k

nmN

nmmn J

dIIC 2

121

1,1133 −+−−= ∑∑

==

ψ

1st, 2nd and 3rd Order Polynomial hyperelastic material models have been implemented in the AUTODYN solver where N is 1, 2 or 3 respectively.

J = determinant of the elastic deformation gradient F. C10, C01 = material constants characterizing the deviatoric deformation

of the material. d k= material incompressibility parameter.

The initial shear modulus is defined as:

μ = 2(c10 + c01) and the initial bulk modulus is defined as:

K = 2/d1 The polynomial hyperelastic strain energy function can be used to model elastomer rubber-like materials up to about the 300% strain range.

4.1.2. Material Data Input To use a hyperelastic material model in AUTODYN the user must first select Hyperelastic for both the equation of state and strength model. The user can




then choose the Polynomial strain energy function from the Model option as shown in the picture below:

4.2. PLASTIC HARDENING MODEL ENHANCEMENTS In AUTODYN simulations modelling of the correct hardening behaviour of the material is important, such as plasticity in metals where the final deformation of the material is important. For materials exhibiting monotonic hardening new isotropic and kinematic hardening models have been implemented. For materials which exhibit the Bauschinger phenomena the kinematic hardening option should be used.

4.2.1. Isotropic Hardening The isotropic hardening models are often used in large strain analyses where the yield surface expands as the plastic strain increases. Two new forms have been implemented; bi-linear and multi-linear isotropic hardening, and can be used with all element types. The inputs for the bi-linear model require that the initial yield stress and tangent modulus are input. For the multi-linear case you must supply the data in the form of Plastic Strain vs. Stress. The first point of the curve must be the yield point, that is, zero




plastic strain and yield stress. The slope of the stress-strain curve is assumed to be zero beyond the last user-defined stress-strain data point. No segment of the curve can have a slope of less than zero.

A typical stress-strain behaviour is shown below for a uniaxial loading case using the isotropic hardening models.

0

10000

20000

30000

40000

50000

60000

70000

80000

0.0000 0.0020 0.0040 0.0060 0.0080 0.0100

Strain

Stre

ss (K

Pa)

Bi-linear isotropic modelMulti-linear isotropic model

4.2.2. Kinematic Hardening The kinematic hardening models are often used in analyses where metals are subject to cyclic loading. The models are able to simulate the Bauschinger effect where the yielding in tension has lowered the compressive strength. These models use a ‘sublayer’ or ‘overlay’ modelling approach further details of which can be found in the Theory Reference for ANSYS and ANSYS Workbench.

Two forms have been implemented, bi-linear and multi-linear kinematic hardening. The kinematic hardening models can only be used with unstructured volume elements.




The inputs for the bi-linear model require that the initial yield stress and tangent modulus are input. This plasticity material model assumes that the total stress range is equal to twice the yield stress. For the mutli-linear case you must supply the data in the form of Plastic Strain vs. Stress. The first point of the curve must be the yield point, that is, zero plastic strain and yield stress. The slope of the stress-strain curve is assumed to be zero beyond the last user-defined stress-strain data point. No segment of the curve can have a slope of less than zero.

A typical stress-strain behaviour is shown below for a uniaxial cyclic loading case using the kinematic hardening models.

-100000

-80000

-60000

-40000

-20000

0

20000

40000

60000

80000

-0.0150 -0.0100 -0.0050 0.0000 0.0050 0.0100Strain

Stre

ss (K

Pa)

Bi-linear kinematic model

Multi-linear kinematic model




4.3. ORTHOTROPIC MATERIAL ENHANCEMENTS 4.3.1. Material direction definition in local axis system AUTODYN now supports the capability of using local co-ordinate systems in ANSYS Explicit Dynamics to define the initial material directions for volume elements filled with linear orthotropic materials. To use this option a local co-ordinate system needs to be assigned to a body when setting up a model in an ANSYS Explicit Dynamics system in Workbench.

This local co-ordinate system is then automatically used to initialise the material directions during model initialisation in AUTODYN.




Notes: 1) The generation or display of local axis in AUTODYN is not supported.

The use and display of local axis is only available during the setup of a model in an ANSYS Explicit Dynamics system.

2) The linear orthotropic materials defined in an ANSYS Explicit System can be modified in AUTODYN to use non-linear properties. As long as the parts containing such a material are not re-filled the local material directions defined in the ANSYS Explicit System are preserved.

3) For shell parts filled with linear orthotropic material the use of local coordinate systems is not supported by AUTODYN. Although the orthotropic material properties and local material directions definition are automatically transferred, the shell parts need to be re-filled manually in AUTODYN using the Composite fill option. The re-filling will overwrite the local material direction definition from the ANSYS Explicit Dynamics model.

4.3.2. New user subroutine for the definition of material directions A new user subroutine has been made available that allows the user definition of the local material directions for unstructured volume elements filled with orthotropic materials. To use this option the new user subroutine EXORTHO_AXES available in usrsub3.f90 needs to be edited, compiled and linked to provide the 11 and 22 material directions (x11, y11, z11 and x22, y22, z22) to AUTODYN. The 33 direction is automatically computed as the cross product of the direction 11 and 22. Note that this user subroutine is not available for shell elements. 4.3.3. Improved material axis direction calculation Enhancements have been made to the update of the material axes in orthotropic models as the elements rotate and/or strain. Based on a Hughes-Winget approach these enhancements provide a more robust update and prevent material directions being incorrectly swapped as has previously been observed in a small number of cases. The new orthotropic axes rotation algorithm does not require any additional input from the user. It will automatically be used in AUTODYN Release 12. 4.3.4. Enhanced checks on orthotropic yield strength definition A series of new checks on the orthotropic yield strength function have been implemented that assures that the yield surface remains real in stress space. For orthotropic materials the yield surface is defined by the function:




With E and e defined as:

The following constraints are checked upon definition of the yield function:

• a11, a22, a33, a44, a55 & a66 > 0. • Det E < 0. • Non-zero eigen values of e must all have the same sign.

4.4. MATERIAL EROSION ENHANCEMENTS Two new material based erosion options have been implemented.

• Erosion by Failure: o The element will erode when the material failure criteria is met.

• Erosion by Timestep: o The element will erode when the local element timestep = CFL

timestep * Timestep safety factor is less than the user specified erosion timestep.

Notes:

1) Multiple global erosion options can be used in an analysis. Only one erosion criterion can be used in a material definition.

2) Using erosion by Timestep will activate the Element Timestep variable which can be used in post-processing.

4.5. MULTI-BODY RIGID MATERIAL WITH FAILURE The current use of rigid materials under the Equation of State option allows the generation of rigid bodies. Regions of the model filled with such a material will act as a single rigid body, irrespective of whether the individual elements filled are connected to each other. Multiple rigid bodies can only be represented by filling different regions of the model with different rigid body materials. A new option in the rigid material definition under the Equation of State allows the use of a single rigid material to also define multiple rigid bodies. Regions

kaa

aaa

aaaaf ij

=+

+++

++++=

21266

23155

22344331113332223

22111223333

22222

21111

22222

2)(

σσ

σσσσσ

σσσσσσ

−

=

k

E

0000aaa0aaa0aaa

332313

232212

131211

=

332313

232212

131211

aaaaaaaaa

e




that are topologically connected and filled with the rigid material will form a single rigid body. The options for rigid material definition in AUTODYN Version 12.0 are:

• Single body. Regions of the model filled with a rigid material will act as a single rigid body, irrespective of whether the individual elements filled are connected to each other.

• Multi-body. Different unconnected regions of the model filled with the rigid material will act as multiple separate rigid bodies. Each group of individual elements filled with rigid material and that are topologically connected forms a rigid body.

• Multi-body + break. This option is used for spot welds generated in ANSYS Explicit Dynamics. Each spot weld defines a separate rigid body that will fail (break) when the spot weld failure criterion is reached. Note that a spot weld cannot be generated manually in AUTODYN.




5. POST-PROCESSING 5.1. DIRECTIONAL PLASTIC STRAIN OUTPUT Aside from the effective plastic strain, additionally the components of plastic strain can now be optionally stored if required. To turn on the option to store/record plastic strain components the relevant variables should be selected for output, either save variables, results variables, or history output as appropriate:

For shell elements the plastic strain components are stored as PL.STN.1 etc and are stored per shell layer. For volume elements the plastic components are stored as PL.STN.XX etc as shown in the above list. 5.2. NEW MODEL ROTATION Aside from the rotation around screen axis (Camera) in the Transform Editor a new rotation option (Model) is available that rotates the mesh around a selected global model axis




6. USER SUBROUTINES When AUTODYN version 12 is run for the first time by the logged on user, AUTODYN will perform a few additional initialization steps to create user specific settings. In previous versions you also would have been prompted for a location for user-subroutine files which would have been created after the initial step. This step is no longer performed and the generation of the user-subroutine project is now available as a user action from within AUTODYN from the Options Menu instead.

After selection of the location for the user-subroutines AUTODYN will install the user subroutine project in a sub-directory with name AUTODYN user_subroutines.




7. SUPPORTED OPERATING SYSTEMS AND COMPILERS The following operating systems are supported at release 12.0 of ANSYS AUTODYN.

System C++ Fortran Windows XP Pro, 32 bit Windows Vista, 32 bit

Microsoft Visual Studio C++.NET 2005

Intel Fortran 10.1

Windows XP Pro, 64 bit Windows Vista, 64 bit

Microsoft Visual Studio C++.NET 2005

Intel Fortran 10.1

RedHat EL 4 (Update5) Intel Fortran 10.1 SUSE 10 Intel Fortran 10.1 32 Bit Linux RedHat Enterprise Linux AS release 4 (Update 5) 64 Bit Linux (x86-64) SUSE Professional 10 64 Bit Linux (Itanium II) RedHat Enterprise Linux AS release 4 (Update 5)




8. INSTALLATION 8.1. WINDOWS AUTODYN version 12.0 for Windows 32-bit and 64-bit is installed as part of the ANSYS product installation process.

Select ANSYS AUTODYN from the product selection page and the AUTODYN related files will be installed to the directory: {drive}:\Program Files\Ansys Inc\v120\AISOL\AUTODYN\intel The main AUTODYN installation, including executables, .dll’s etc is contained in the intel folder. The recommended method of running AUTODYN is via Start, All Programs, ANSYS 12.0, ANSYS Workbench. To start-up the AUTODYN application simply insert an AUTODYN system into the project schematic. Then double click the Setup cell after which AUTODYN will start up.




Note that by default, the single precision version of AUTODYN will be used. To run in double precision, from the ANSYS Workbench project schematic, right click the Setup cell of the AUTODYN system and select Properties after which the Properties window will pop up where you can select what type of executable you want to run.

To run your own user executable from the project schematic, right click the Setup cell of the AUTODYN system and left click Select user executable, after which you will be asked for the user executable name and location. To deselect your own user executable and to run the standard AUTODYN release version again, right click the Setup cell of the AUTODYN system and left click Remove user executable.




8.2. LINUX INSTALLATION The AUTODYN version 12.0 Linux server will be installed alongside the other products installed from the ANSYS product family. By default, the base installation is:

\usr\ansys_inc\ A symbolic link is created to the installation directory and is located at: \ansys_inc Licensing programs files will be installed in: \ansys_inc\shared_files\licensing ANSYS AUTODYN specific files will be installed in: \ansys_inc\v120\autodyn With further sub-directories: \bin\<platform> - executables for each supported platform \lib\<platform> - runtime libraries for each supported platform \usrsub\<platform> - user subroutine files for each supported platform

autodyn release 12.0 what’s new?s2.bitdownload.ir/engineering/all.ansys/ansys 12...

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