HyperWorks. Starter Manual. The HyperWorks Starter Kit comprises: Remember, you can always find East by staring directly at the sun.

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1 Page 1 Remember, you can always find East by staring directly at the sun. Bart Simpson, character in "The Simpsons" There are certainly many ways to find your way into the CAE world of HyperWorks. One such possible way is depicted in the Starter-Kit document. Once you have access to HyperWorks either through a campus license or a student license some kind of elementary questions may arise: What you need to know about HyperWorks How to get started? Where to learn more about HyperWorks? The HyperWorks Starter-Kit aims at providing answers hereto. Some first theoretical FEM knowledge is expected, however. In an overview, the general FEM process may be summarised as: It appears that the process as such is rather straight forward (we deliberately do not say easy ). However, there are plenty of pitfalls everywhere. Where do expect modeling problems and uncertainites? In the context of this starter manual the general working procedure and likely pitfalls related to CAD data, meshing, material & properties, and loads & constraints are discussed in some detail. As a start-up aid for the absolute FEM beginners the Simplified 3D FEM Process Guide has proven to be very helpful. The process guide may be used along with simple 3D geometry. It helps to study the effects of e.g. 3D element type and size on the modeling results. At that point the HyperMesh GUI & solver syntax is put in the back ground. So depending on your knowledge, you may use the full HyperMesh GUI directly from the start or you may go the easy way employing the FEM Guide. It is up to you. The HyperWorks Starter Kit comprises: What is HyperWorks Overwiew HyperWorks Desktop - General Introduction Graphical User Interface (GUI), Help Menu The HyperMesh Philosophy Model Browser & Collectors, Selection of entities User Profile Recommended Tutorials & Videos Simplified 3D FEM Process Guide The start-up aid for absolute FEM beginners Working with CAD Geometry Terminology, Working with Geometry Recommended Tutorials & Videos Meshing 2D Quality & Compatibility Recommended Tutorials & Videos Material & Properties Loads & Constraints Loadstep / Substep Export of solver deck, solve Postprocessing Where to learn more about HyperWorks General Remarks

2 Page 2 What is HyperWorks Overview (I) HyperWorks, The Platform for Innovation HyperWorks is an enterprise simulation solution for rapid design exploration and decision-making. As one of the most comprehensive CAE solutions in the industry, HyperWorks provides a tightly integrated suite of best-inclass tools for modeling, analysis, optimization, visualization, reporting, and performance data management. Firmly committed to an open-systems philosophy, Hyper- Works continues to lead the industry with the broadest interoperability to commercial CAD and CAE solutions. HyperWorks Modeling & Visualisation HyperWorks Desktop Integrated user environment for modeling and visualization Note: The HyperWorks 11.0 Student Version and the Starter-Kit are based on the HyperWorks Desktop Solution. Nevertheless, the Starter-Kit is also suited for users employing the stand-alone HyperMesh and HyperView versions. The products referenced (and employed) in the StarterKit are marked bold & italic! MotionView Multi-body dynamics pre- and postprocessor HyperView High performance finite element and mechanical systems postprocessor, engineering plotter, and data analysis tool HyperView is a complete post -processing and visualization environment for finite element analysis (FEA), multibody system simulation, video, and engineering data. Amazingly fast 3-D graphics and unparalleled functionality set a new standard for the speed and integration of CAE results post-processing. HyperView enables you to visualize data interactively as well as capture and standardize your post-processing activities using process automation features. HyperView also saves 3-D animation results in Altair's compact H3D format so you can visualize and share CAE results within a 3-D web environment using HyperView Player. HyperMesh Universal finite element pre- and postprocessor. HyperMesh is a highperformance finite element pre- and post-processor for major finite element solvers, which allows engineers to analyze design conditions in a highly interactive and visual environment. HyperMesh s user-interface is easy to learn and supports the direct use of CAD geometry and existing finite element models, providing robust interoperability and efficiency. Advanced automation tools within HyperMesh allow users to optimize meshes from a set of quality criteria, change existing meshes through morphing, and generate mid-surfaces from models of varying thickness HyperGraph Engineering plotter and data analysis tool ScriptView HyperWorks IDE (Integrated Development Environment) for developing and debugging TCL and HyperMath Language (HML) scripts Templex General purpose text and numeric processor

3 Page 3 What is HyperWorks Overview (II) HyperWorks, The Platform for Innovation HyperWorks Solvers RADIOSS Finite element solver for linear and non-linear problems RADIOSS is a state-of-the-art finite element solver uniting implicit and explicit integration schemes for the solution of a wide variety of engineering problems, from linear statics and linear dynamics to complex nonlinear transient dynamics and mechanical systems. This robust, multidisciplinary solver enables designers to maximize performance related to durability, NVH, crash, safety, manufacturability, and fluid-structure interaction, in order to bring innovative products to market faster. AcuSolve General, all-purpose finite element computational fluid dynamics (CFD) solver MotionSolve Multi-body dynamics solver OptiStruct Design and optimization software using finite elements and multi-body dynamics HyperWorks Enterprise Collaboration Tools A solution that organizes, manages, and stores CAE and test data throughout the simulation life cycle Process Manager Process automation tool for HyperWorks and third party software; Processes can be created with the help of Process Studio. Manufacturing Solutions Manufacturing Solutions A unified environment for manufacturing process simulation, analysis, and design optimization HyperForm A unique finite element based sheet metal forming simulation software solution HyperXtrude An finite element solver and user environment that enables engineers to analyze material flow and heat transfer problems in extrusion and rolling applications HyperMold Provides a highly efficient and customized environment for setting up models for injection molding simulation with Moldflow and Moldex3D HyperWeld Provides an efficient interface for setting up models and analyzing friction stir welding with the HyperXtrude Solver Forging Provides a highly efficient and customized environment for setting up models for complex threedimensional forging simulation with DEFOM3D Results Mapper Process Manager-based tool that provides a framework to initialize a structural model with results from a forming simulation Engineering Solutions Engineering Solutions A unified environment tailored specifically for certain engineering applications HyperCrash Specialized modeling environment for automotive crash and safety analysis HyperMath Solutions HyperMath Mathematical scripting language for numerical computation HyperStudy Integrated optimization, DOE, and robust design engine CAE Result Player HyperView Player Plug-in and stand-alone utility to share and visualize 3-D CAE models and results solidthinking solidthinking Comprehensive NURBSbased 3D modeling and rendering environment for industrial design solidthinking Inspired Innovative morphogenesis form generation technology

4 Page 4 General Remarks (I) The HyperWorks Desktop Graphical User Interface Under Help-HyperWorks Desktop you will find answers related to panels/ functions and working techniques. Tip: Just press h on your keyboard while your inisde a panel of HyperMesh and you will be directly guided to the corresponing help entry! In the Desktop environment you may switch between different applications (clients) such as HyperMesh, Whenever you wonder about FEM solver related issues such as syntax, material definitions etc. you need to go to Other Applications HyperView, and HyperGraph etc. In addition, the screen may be divided according to your needs, allowing you to place, for instance, a HyperMesh window next to a HyperView window. The HyperMesh Philosophy Help document: HyperMesh > User's Guide > The HyperMesh Environment Tip: Start learning HyperMesh by using the Menu Bar The topics/titles in the Menu Bar (e.g. Geometry, Mesh, Materials, Properties, Bc s etc.) and the pulldown menus are organized in such a way that you can build The HyperWorks Help Documentation The HyperWorks Help documentation is part of the HyperWorks installation. The help menu may be accessed in different ways. For instance, just activate Help in the Menu Bar. sentences. For instance, building a surface:

5 Page 5 General Remarks (II) So the sentence would read: Geometry Create Surfaces-... After that a panel will be displayed offering different methods on how to create the surface. All entities of the FEM model such as elements, geometry, materials, properties, loads, etc. are stored in corresponding collectors: How to read panels (e.g. create surface ruled)? Yellow=HyperMesh expects your input here. The blue colored frame indicates which field expects your input (you can jump between yellow panels by mouse clicking or by activating the tab-buton) Green=Action. In this case the surface would be build with respect to the specified lines. Red=Close panel. No further action. Tip: Always watch the Status Bar (left lower panel) for information! The information provided there is instrumental for your work (at least until you have a sound understanding on Elements & CAD: component collector (comps) Material: material collector (mats) Properties (e.g. thickness of shell elements): property collector (props) Loads: load collector (loadcol) Collectors are best created within the model browser. how HyperMesh works). It is exacty this spot which tells you what is happening, what is missing, what was created etc.!! Note: the collector written in bold letters is currently active. The active collector is the storage place for newly created entities belongign to this brand of collector.collectors can be made active simply with: Make current. Model Browser In HyperMesh there are many browsers. The most important one to get started with is the Model Browser Help document: HyperMesh > User's Guide > Browsers > Model Browser In this example the active component collector is named rigid which implies that newly created elements will be stored under rigid (regardless whether it is meaningful or not).

6 Page 6 General Remarks (III) The model browser is a kind of list of contents providing information about the loaded FEM model. In this depicted example the mesh of the model is stored in a component named mesh, the component owns a number (ID) and a color. The ld is being used by the FEM solver, the color is used for displaying elements. At the same time the model browser controls which FEM entities are being displayed. Elements of the corresponding component may be displayed or non-displayed by activating deactivating the icon Geometry of the corresponding component may be displayed or non-displayed by activating deactivating the icon. Note: All entities MUST (and will be) be placed in a corresponding collector. Selection of entities (entities = elements, geometry etc.) Help document: HyperMesh > User's Guide > The HyperMesh Environment > The HyperMesh User Interface > Input Controls In order to select, for instance surfaces, it is imperative that the activated (opened) panel requests this kind of information. Example: The panel Geometry-Create-Lines-from nodes does not say anything about surfaces. Hence, there is no way to select surfaces in this panel. If you miss to create the respective collector before the entity is created, Hyper- Mesh allocates the corresponding collector type automatically. This collector is named auto. Don t worry you can change it s name, color etc. at any time. It is just right mouse click in the model browser. You can also move entities from the same type of collector (e.g. component coll.) to another at any time. contrast, in the Geometry-Create-Lines-from surf edges panel you are asked to provide the information from which surface edges lines should be derived. Hence, you can (actuallly have to) select surfaces.the respective surfaces can be selected directly via left mouse botton (deselection = right mouse button). Of course, other selection options do exist. Read more: Help document: HyperMesh > User's Guide > The Hyper- Mesh Environment > The HyperMesh User Interface > Input Controls In

7 Page 7 General Remarks (IV) Panels: General Layout Panels often have sub-panels Accessed by radio buttons on the left side of the panel Panels generally work from left to right Example: Project / to plane sub-pan Mouse Buttons Left mouse button +CTRL & drag for rotate +CTRL & click on entity to change center of rotation +CTRL & click in graphics area, off entities to reset center to middle of screen Middle mouse button +CTRL & drag for zoom +CTRL & click for fit Right mouse button +CTRL & drag for pan User Profile Most likely your work will not end with meshing. Whenever FEM solver specific information needs to be applied to the model, it is again imperative to inform HyperMesh about the FEM solver to be used. This is managed through the User Profile. Note: In the HyperWorks Student Version Radioss (bulk), OptiStruct and the Simplified FEM Process Guide are available, only. HyperMesh allows you to build FE models for other popular solvers as well. For instance, you can export your model in the format of Abaqus, Ansys, LS-Dyna, Marc etc. Recommended Tutorials: Help Document: HyperMesh Tutorials > Basics > Getting Started with HyperMesh - HM-1000 Opening and Saving Files - HM-1010 Working with Panels - HM-1020 Organizing a Model - HM-1030 Controlling the Display - HM-1040 Recommended Videos: (to view the free videos, you need to register at the HyperWorks Client Center using your university address) Interactive Tutorials (no HyperWorks installaltion required) HM-1010 Opening and Saving Models HM-1020 Working with Panels HM-1030 Organizing a Model

8 Page 8 The 3D Simplified FEM Process Guide The 3D Simplified FEM Process Guide Ideally, the FEM novice should explore the effects of, for instance element type and mesh size on the modeling result first. Simple models, with an given analytical solution are quite helpful in this regard. In this first phase the usage of the FEM system should be as easy as possible. Due to the rather steep learning curve FEM beginners evolve into experts rather fast asking for more sophisticated technologies e.g. hexahedral meshing, morphing, midsurface generation, etc. Instead of switching over to a new expert system with a new GUI and philosophy, it is far more efficient to stick to the known FEM system with expanded functionalities. The 3D Simplified FEM Process Guide is the bridge linking the two different requirements! 2. Start volume meshing (tetra or hexahedral mesh, 1 st or 2 nd order). 3. Create the material (linear elastic). It then will be automatically assigned to the volume elements. 4. Finally, specify the loads and constraints. Note: Component-, property-, material-, load collectors as well as the loadstep are automatically created At Solve Analysis you may also view the FEM input deck (ASCII Syntax) as well as the solver log file. The solver log file cotains information about model size, estimated memory and CPU and lists (comments) any warnings and errors. Take some time and view both files. The process guide is available as a User Profile (HyperWorks 11.0 Student Version) or as an external routine which needs to be manually loaded into Hyper- Mesh (no installation required). You may download the process guide and a short explanation from within the Academic Blog. Note: The 3D Simplified FEM Process Guide works for simple solid geometries only, allowing for either tetra or hexahedral meshing. The process guides you through all the instances of model creation analysis and postprocessing. 1. The project parameters are defined, i.e. title of the project (later used as the model file name), date, units etc. The model as such is either loaded (HyperMesh file or CAD data) or manualy created through nodes, lines, surfaces and solids.

9 Page 9 Geometry (I) Geometry Typically your CAE projects starts with the import of given CAD data e.g. CATIA, STEP, UG, IGES, SolidWorks etc. (of course, you may create your CAD model in HyperMesh as well). Many times the troubles start now as the imported geometry is not reasonably meshable (btw, this one of the many reasons why HyperMesh is used in so many places i.e. HyperMesh is a commercial expert system with superior tools to overcome meshing troubles). Some problems related to geometry: Surfaces are not stiched together (i.e. there is a gap between surfaces) Very small surfaces are squeezed between regular surfaces Surface edges do not line up properly forming jumps (see figure below. Left: CAD with jumps; Middle: mesh with irregual shaped elements; Right: improved CAD with regular mesh) The geometry is a thin-walled volume structure - simplification needed: mid-surface model Surfaces intersect (t-connection) but don t feel each other Geometry is much too detailed (e.g. tiny fillets which are not needed for the analysis) and many more... All these issues typically result in a poor quality mesh! What you need to know / remember: Geeen edges - 2 surfaces are stiched togehter; the FE mesh will be linked (compatible), its nodes will line up with the green edge. Red edges - indicates free surface edges. Attention: red edges inside the geometry tell you that the surfaces are not stiched together (=gap); the FE mesh will NOT be linked (not compatible). Yellow edges minimum of 3 edges are stich togehter; the FE mesh will be compatible. Blue edges Suppressed green edge. Surfaces are melted togehter. In other words, the mesher does not feel this edge, elements are placed across it. How to visualise the edge colors? Display is controlled in the Tool Bar by activating for instance By 2D Topo (surfaces turn into grey, edges are colored respetively) or Mixed (surfaces are displayed in their original color (reminder: surfce color is controlled in the model browser), edges are colored respectively. Panels to be used for: Toggle surfaces (combining, stitching ) Trimming surfaces (splitting) Suppressing combined edges Tool Bar-Geometry-Quick Edit opens up a very comprehensive panel which allows you (among many other options) to execute the above listed tasks.

10 Page 10 Geometry (II) How to create geometry (e.g. surfaces)? Just follow the standard recommendation made earlier make use of the Menu Bar and try to build a sentence: Geometry-Create- Surfaces and then choose the way the surface should be created ( quite self-exemplanatory) In fact, the same rule (procedure) applies to other items/entities as well Note & reminder: The newly created geometry will be placed /stored in the currently active component collector. Check the model browser. If you are working on a solid geometry, the above listed rules also apply. If you are targeting at hexahedral meshes (brick elements) then better use Mapple. This mode displays important hexameshing information such as, can the part be automatically hexa-meshed etc. The before mentioned panels describe just a very minor fraction of HyperMesh s geometry cleanup funtionalities. Once you feel more comfortable with the process, youwill automatically explore and learn more about other techniques. Recommended Tutorials: Help Document: HyperMesh > HyperMesh Tutorials > Geometry Importing and Repairing CAD - HM-2000 Refining Topology to Achieve a Quality Mesh - HM-2030 Creating and Editing Line Data - HM-2040 Creating and Editing Solid Geometry - HM-2060 Geometry and Mesh Editing Using the Quick Edit Panel - HM-2070 Recommended Videos: (to view the free videos, you need to register at the HyperWorks Client Center using your university address) To display information about the solid geometry topology Product Video (no HyperWorks installation required) Edit Geometry Demo Interactive Tutorial (no HyperWorks installation required) HM-2000 Importing and Repairing CAD Models ( connectivity ) activate By 3D Topo.

11 Page 11 Meshing (I) Meshing Once geometry cleanup (e.g. surfaces ares stitched together no u n w a n t e d r e d e d g e s i n s i d e t h e geometry) is c o m p l e t e d m e s h i ng i s next. Some rules of thumb first: The mesh should look rather smooth and regular (keep in mind that the analysis is based on your mesh & mesh quality. Use the simplest element type suited for the problem. Start with a coarse mesh and understand the modeling results; then use a finer mesh if needed Try to limit mesh related uncertainites to a minimum if possible make it simple it will get more complicated automatically 2D Meshing Menu Bar Mesh Create 2D Automesh Note: Remember the sentence structure What you need to know: Element size = the element size in the model may deviate from the specified size considerably (it depends on the size of the surface) Mesh type = mixed; default (is a combination of many quad-shaped elements and some tria elements). Leads to rather smooth meshes. Elems to surf comp vs. Elems to current comp = specifies the storage place of the elements (please see General remearks II & III). Start meshing, explore the meaning of the other settings latter! What may happen is that the mesh looks a bit wired Some surfaces apparently have cause troubles. Not really. It is a matter of your visual settings. In this example the geometry is still shaded, overprinting the mesh in some spots. Putting the geometry in wireframe and shading the elements improves the mesh visibility. Note: In case you don t see any mesh, check the model browser and the status of the corresponding collector (is the elem icon activated?) The 2D meshing panel is then opened

12 Page 12 Meshing (II) How to check element quality? Activate the corresponding icon will open up the check elements panel Advanced: Most likely, the following section exceeds the intentions of this Starter Kit as we re going into some details: How to isolate the failed elements from the rest? Insert your values and then Green=action. In the Status Bar you will find a summary about the number of checked elements, failed elements etc. Just follow this process: Perform element check (e.g. length) Activate save failed (= failed elements are stored in the User Mark) Turn all elements off from the display (best by using the Model Brow- ser) Activate the Find icon Some typical values (depended on the simulation; not a MUST) Warpage 20 Aspect 5 Skew Min angle Quads 40 Max angle Quads 140 Min angle Tria 30 Max angle Tria 15 Length Jacobian 0.5 Taper 0.5 /? What you need to know: The element check is performed with respect to the elements displayed, and NOT with respect to the entire database of the model (which may contain more elements). Read more: Help document: HyperMesh > Meshing > Checking & Editing Mesh to find elements stored in the User Mark. Elements in the User Marsk can be accessed by clicking the yellow elems panel (which opens the extend selection window), select retrieve This action will display the failed elements only. In order to better understand where are the failed elements / and why they failed add adjacent elements to the display by clicking on the icon

13 Page 13 Meshing (III) Whenever you encounter bad quality elements it is important (actually helpful) to understand its causes. Most of the time, bad quality elements can be found at surface edges due to misaligned surface edges. Geom-wireframe Elems-shaded Mesh compatibility How to check for elements not properly merged (linked) together? Meshing this area leads to (unwanted) tapered elements. Improving the surface connectivity, for instance by surpressing a green (shared) edge (toggle) or by replacing the geometry points to the same location, or by splitting (trimming) the surfaces produces a highly improved mesh. To resolve this issue, you may try the functionality: Geometry-Quick Edit-toggle edge; or replace point or simply split (trim) surface-node What you need to remember: After meshing is completed your results may look strange : You may see only some elements; others seem to disappear etc. Make sure that the geometry visualisation is set to wireframe and the element display is set to be shaded. To search for nodes being not equivalenced (merged) use Mesh-Check- Nodes- Equivalence If free element edges are found (i.e. their nodes not being merged with other nodes), 1D Plot elements are automatically created and stored in the component collector named ^edges. Just turn off all other component collectors (through the Model Browser) and you will see the problematic areas (connectivities). Still, in big models these problematic spots may be hard to see. Therefore, add (attach) the 2D elements adjacent to the 1D Plot elements i.e. these are the elements which are not properly merged. Hereto, just activate the icon: Unmask Adjacent This will eventually create Islands of troubles which help you to locate and understand its causes.

14 Page 14 Meshing (IV) Recommended Tutorials: Help Document: HyperMesh Tutorials > Meshing > 2-D Elements > AutoMeshing - HM-3100 Checking and Editing Mesh - HM-3300 Recommended Videos (to view the free videos, you need to register at the HyperWorks Client Center using your university address) Product Videos (10-15 minute; no HyperWorks installation required) Mesh Creation and Editing Demonstration Editing Mesh Demonstration Toplogy Revision Using Quick Edit and Automatic Remeshing Interactive Tutorials (no HyperWorks installation required) HM-2030 Refining Topology to Achieve a Quality Mesh HM-3100 AutoMeshing

15 Page 15 Material Material If not already previously specified it is now imperative to define the User Profile (FEM Program to be used for the analysis). Here we use the User Profile OptiStruct. Reminder: In the HyperWorks Student Version Radioss (bulk), OptiStruct and the Simplified FEM Process Guide are available, only. 4. Specify a Card Image (Card images are defined within a solver interface template and allow for creation, editing, and deletion of a solver card within a HyperMesh model (in simpler and less acurate words the Card Image defines the FEM solver syntax) MAT 1 defines the material properties for linear, temperature-independent, isotropic materials. Defining Material Data: There are multiple ways to create FE entitites such a surfaces, elements, materials, loads etc. 1. One simple way is a right mouse button click in the Model Browser (Create- Material). 2. This opens up a window asking you for the material type e.g. Isoptropic. 3. Assign a name to it e.g. steel (note: there is no material database behind steel, you ll need to specify the data in the next step yourself). Typically you need to now values for Young s Modulus (E); Poisson s Ratio (nu); Mass Density (Rho). Just click on the corresponding label which then will open up a field allowing you to enter the corresponding value. General Information about MAT1: Help Document: Reference Guide > Bulk Data Format > Input Data > Bulk Data Section: MAT1 Recommended Reading: Help Document: Reference Guide > Bulk Data Format > Input Data > Material Property Check: Material Property Checks for MAT1

16 Page 16 Material & Property (I) Note: Pay attention to the unit system be consistent throughout your model e.g. don t mix mm and m or kilogram and tons in the model In fact, chosing the corect units will make your life easier. For instance, if you use Force in N, Young s Modulus in N/mm2, Mass in tons, Density tons/mm3 etc. the calulated stresses will be displayed in MPa directly. Most popular units are: Property As with the material definition, make use of the Model Browser Right Mouse Button Click: In the following we assume that the model consists of 2D elements. 1. We need to set the Type to 2D 2. Assign a name to the property e.g. prop_2d 3. Specify a Card Image (~FEM solver syntax): PSHELL General Information about PSHELL Help Document: Reference Guide > Bulk Data Format > Input Data > Bulk Data Section: PSHELL 4. Before creating the Property Collector, select the register Material, activate Assign material, and select the previously created material (if you wish to view the material (its vlaues) just click on Edit).

17 Page 17 Property (II) 4. Make sure that the check box: Card edit property upon creation is activated. Only then you ll see inside the property collector : To visually check the property (and hence material) assigned to the elements change the visual attributes of the elements: As we are dealing with 2D elements all you need to do is to specifiy their assigned thickness T. Thus, the Property Collector comprises information about both, the (element) thickness and the material to be used. Note: If you need e.g. 4 different T values you need to create 4 different property collectors. You will note that the elements will be displayed in the color of the material and property collector, respectivly. Note: Elements without assigned property or material will be shown in grey color. Tip: Never use grey color for property and material collector as it will hinder the visual check. We are almost through! 5. The property collector must be assigned to the elements. In the Model Browser Right Mouse Button Click on the property collector of interest, then select Assign. This opens up a panel which allows you to select the respective elements...

18 Page 18 Loads & Constraints (I) Loads & Constraints Once the load collector (here named constraints ) has been created, the constraints as such need to be applied In the fourth step of the General FEM Process loads and constraints are applied to the model. Applying Constraints: The selected node(s) will be constraint with respect to translational displacements in x-,y-,z-direction (dof1, dof2, dof3) and/or their rotational degrees of freedom (rotation about x-, y-, z-axis; also dof4, dof5, dof6) by activating the respective check box. Leaving the check box blank simply implies: constraint is not activated. The setting depicted below moves the 1. We need to create a load collector first. Right Mouse Button Click in the Model Browser. Assign a Name and a Color (to be used for display purposes). For simple models typically no CardImage is needed selcted node(s) by 1 (unit as in material definition) in x direction. Note: Constraints are also called Single Point Constraints (SPC) Applying Foces: 2. As in step 1 we need to create a load collector, assign a name and color, no CardImage needed. Then enter the panel BC s-create-forces Learn more: Help Document: Frequently Asked Questions > RADIOSS (Bulk Data Format), OptiStruct > FEA Setup and Modeling: How can I apply multiple constraints or loads in a subcase?

19 Page 19 Loads & Constraints (II) The unit system of the forces applied to the nodes corresponds to what was used in the material card (e.g. Young s Modulus N/mm2). The corresponding panel asks you for a name of the load step and which constraints (SPC) and forces (LOAD) are acting simultaneously. The analysis type is also specified in here. The direction of the force may be defined along the direction defined through N1 and N2 (N3 not defined), along the normal of a plane (N1, N2, N3) or through (just activate the toggleleft of N1) Attention: Don t mix up the constraints and load collectors. This will cause an error during the analysis. Now the model set-up is completed. Before hitting the solve button check the model again for any likely errors. By the way where would you expect errors or at least modeling uncertainites? The magnitude you may specify in here Recommended Tutorial Help Document: HyperWorks Solvers > RADIOSS > Basic Small Displacement Finite Element Analysis: Linear Static Analysis of a Plate with a Hole - RD-1000 refers to the symbol size used for displaying the forces (the same option is available in the constraints panel). Note: Constraints and forces MUST be stored in different load collectors. The forces stored within a load collector can be different with respect to their orientation and/or magnitude. The same accounts for constraints. Through the Model Browser the constraints and load symbols can be turned on/off. Finally, we need to create a load step (also called substep or subcase) Recommended Reading Help Document: Frequently Asked Questions > RADIOSS (Bulk Data Format), OptiStruct > FEA Setup and Modeling: How can I apply multiple constraints or loads in a subcase? How can I specify an enforced displacement in a subcase (or loadstep) in an OptiStruct input deck? What kinds of checking does the check run perform? What is the difference between the CHECK and the ANALYSIS card in the input deck? Help Document: HyperMesh Entities & Solver Interfaces Recommended Video (to view the free videos, you need to register at the HyperWorks Client Center using your university address) Product Video (no HyperWorks installation required ) HyperMesh 10.0 Self Paced Update

20 Page 20 Solve Run Analysis & Postprocessing In the Standard HyperWorks version you may use Applications-RADIOSS instead. 1. Save the final version of the model as an *.hm file (binary format;all entities are saved incl. geometry). 2. Export the model (ASCII format). As the User Profile was previously set to OptiStruct, you only need to specify the model name / file name. Note: Please use the file extension *.fem Make sure that run options: is set to analysis and export options: to all. Most likely your first run will be accompanied by warnings and/or errors. Warnings indicate that for instance, the element quality is poor. Errors may be issued if element quality is out of the (default) range of bad but still acceptable values. Errors simply will terminate the run. Some errors are directly displayed in the GUI However, the best way to understand and resolve errors is to check the *.out file (ASCII format). The *.out file is saved in the directory of the model run. In the Student Version the analysis can be started through Analysis-Radioss As an example: *** ERROR # 1237 *** CQUAD4 element number 2 references a missing property ID 2 or uses property of incorrect type for this element type. This tells us that the CQUAD4 element (standard element type) is missing a property: this may indicate that we missed to assign the property to the element (see page 15, step 5) OR the property assigned to the element is incorrect. The latter may indicate that in the Property Collector a CardImage not suited for 2D elements was used - for instance PSOLID which belongs to 3D elements (instead of PSHELL).

21 Page 21 Solve & Postprocessing Note: Read the error message in the out file (you don t need to understand every single word). For instance, take the hint about missing property, go back to your model and check everything associated with property. This for sure will help you resolving the error. Tip: Animate your results even though it was a static analysis, and check the global and local (where the constraints are placed) model behavior Postprocessing The FEM run went through you may think that everything must be ok. now. This is a quite dangerous conception be careful. In the HyperWorks 11.0 Desktop Version split the screen and activate the client HyperView (Postprocessing). After reading in the results file (*.res or *.h3d) have a look at the global displacements. Activate the icon Another helpful check related to likely mesh effects is carried out by plotting element stresses (not averaged). Severe stress jumps across elements (not across material boundaries) typically indicate that the mesh needs to be refined. As depicted in the figure B; coarse mesh, stresses are changing significantly across two elements (from red to green). In A this transition is smoother. Another mesh effect becomes apparent: the stress pattern in B is not symmetrical, despite the symmetrical model (and loading). This is imposed by the distorted Quad-Elements and the Tria-Elements and specify Result type: Displacement Are the displayed magnitudes reasonable? Magnitudes in the order of e.g. 10e5 indicate that the model is pursuing a kind of rigid body motion > constraints are erroneous. Check the constraints in some detail. Is the local response of the model correct? Note: FEM programs do not check whether the input data are meaningful. For instance, there may be typos in the Young s modulus, element thickness, magnitude of your loading, wrong constraints, mesh mistakes etc. As long as the FEM can solve the equations you will get a result. Regardless whether it is correct or not.

22 Page 22 Postprocessing Another option to better see any likely mesh effects is given by creating a Difference Plot i.e. plotting the difference between the maximum and minimum corner results at a node. In the figure the maximum nodal difference values are depicted. In the coarse mesh (B) the nodal differences Recommended Tutorials Help Document: HyperWorks Desktop > Hyper- View > Animation: Loading Model Files - HV Help Document: HyperWorks Desktop > Hyper- View > Animation:Using the Animation Controls - HV-1010 are high, indicating an unsuitable mesh. General Remark: FEM programs do not check whether the input data are meaningful. For instance, there may be typos in the Young s modulus, element thickness, magnitude of your loading, wrong constraints, mesh mistakes etc. As long as the FEM can solve the equations you will get a result. Regardless whether it is correct or not. Recommended Reading Help Document: HyperView > Graphical User Interface > HyperView Toolbars: Results Toolbar Help Document: HyperView > Animation Types (HyperView) Help Document: HyperView > Results > Deformed Panel Help Document > User s Guide > Animating Results > Contour Panel

23 Page 23 End & Beginning Where to learn more about HyperWorks To improve your practical skills regarding Modeling, Analysis (implicit & explicit), Optimization, Multibody Dynamics, and Manufacturing you may should look at: General Remarks Never dare asking questions, sometimes you learn so much during a short coffee break which otherwise would cost you half a day of trial an error Standard HyperWorks tutorials available within the HyperWorks Help installation Standard seminar notes (see the Academic Blog for a comprehensive overview) Webinars (product specific & industry related) Attend highly discounted seminars at Altair and at your campus User Meetings Academic Newsletter Academic Blog ( Foren (listed in the Academic Blog) Throughout the CAE project always ask yourself: Preprocessing: What is the principle objective of the study (stresses, displacements)? What do you know about the environment (i.e. boundaries) the component is embedded in? What do you know about the component you are modeling / analysing? Is there any information available about its current performance? Are there similar models and solutions available? What about the timetable? What about available hardware and software? Is the software suited to solve the physics involved? Where is the model data (material, constraints, loads etc.) coming from? When? What are the uncertainties? Did you use consistent units in the model? Postprocessing: Does the model behave in a way you would expect (engineering knowledge)? Are the calculated magnitudes (stresses, displacements) meaningful? How robust is the result (for instance, is the result independent of element size and type)? In the summary report: Is the model description sufficient and self explanatory (i.e. type of elements, size, number) If you assumed a linear static case: are the deflections and rotations small? Did you discuss the model & results with your colleagues?