workbench动力学分析实例.ppt

WS 2-1ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Workshop 2Simulate the Crushing of an Empty Soda Can Workshop 2.Simulate the Crushing of an Empty Soda CanWS 2-2ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualWorkshop Goal and Procedure Goal:Crush an aluminum beverage can and allow it to“springback”Procedure:Create an Explicit Dynamics(ANSYS)Analysis System ProjectSelect the units system and define the material propertiesImport,modify,and mesh the soda can geometryDefine analysis settings,boundary conditions,and external loadsInitiate the solution(AUTODYN-STR)and review the resultsWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-3ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 1 Create the Project SchematicStart ANSYS Workbench and follow the sequenced steps using the abbreviations shown below:DC=Double Click with Left Mouse ButtonSC=Single Click with Left Mouse ButtonRMB=Right Mouse Button SelectionD&D=Drag and Drop=Hold Left Mouse Button down on item while dragging it to new location and then release it(i.e.,Copy or Move)DC1.Create an ANSYS Explicit Dynamics Analysis System ProjectWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-4ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 2 Specify the Project Units2.a Select MKS for the Project Units from the Units List provided2.b Request that Native Applications in Workbench have their values be Displayed in the Project Units2.c Check those unit systems to Suppress from appearing in the Units List Note:Engineering Data is native in Workbench,but Mechanical is NOT at this time(but will be in the future).Workshop 2.Simulate the Crushing of an Empty Soda CanWS 2-5ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 3 Define Engineering Data Material3.a Edit the Engineering Data cell to add a material to the default library.3.b Select the last slot under Engineering Data to define a new material model.SC3.c Enter material model name:“My_Aluminum”Note:An existing material model in the Explicit Materials library could have been selected,but there are restrictions on element types that can be used with certain material models,which will be discussed later.DCWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-6ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualDCDCDCStep 3 Define Engineering Data Material.SC3.e Add the following Physical Properties to the material definition:DensityIsotropic ElasticityBilinear Isotropic Hardening3.d Make sure the new material is active in order to define its propertiesWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-7ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 3 Define Engineering Data Material.3.f Enter the following values:Density=2710 kg m-3Youngs Modulus=7e10 PaPoissons Ratio=0.30Yield Strength=2.9e8 PaTangent Modulus=0.0 PaSince the material is sufficiently defined,the blue question marks and yellow fields are no longer present in the data table.Note:The resulting stress-strain curve is elastic perfectly plastic.No strain hardening can develop.Workshop 2.Simulate the Crushing of an Empty Soda CanWS 2-8ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 3 Define Engineering Data Material.3.g Return to the Project Schematic3.h Save the Project by selecting the“Save As.”icon and Browse to the directory indicated by your instructor.Use the name“empty_soda_can”for the Project name.Note:Saving the Project saves all of the important files.The Project may also be Archived,in which all of the supporting files are compressed and saved in one file.Workshop 2.Simulate the Crushing of an Empty Soda CanWS 2-9ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 4 Import and Modify the Geometry4.c Workbench has now identified the geometry file(note green checkmark in Geometry cell).It is now OK to Double Click on“Geometry”,as the new default action is to Edit the geometry.Default actions are shown in bold type after RMB selects.RMBSC4.a Import the geometry by the procedure shown.Do NOT Double Click on the“Geometry”cell.4.b Browse to the DesignModeler 11.0 SP1 geometry file named:“soda_can_filled_110.agdb”RMBSCWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-10ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 4 Import and Modify the Geometry.4.d Suppress the solid“Soda”and the surface body“Hole”.RMBSC4.e Generate the changes in the geometry.Although additional modifications could be made,but none are needed.4.f Save the entire Project via the DM“Save”icon.Workshop 2.Simulate the Crushing of an Empty Soda CanWS 2-11ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 5 Edit the Model in Mechanical5.a Edit the model in Workbench Mechanical.Since Edit is the default action,double-clicking on the Model cell is also acceptable here.RMBSC5.b Select the MKS Units systemRecall that Mechanical is not native in Workbench,so the Units here may not match the Project UnitsNote:Although the unit system used for data entry and post-processing is the MKS system,the actual unit system used by the AUTODYN solver is the mm-mg-ms system,because it provides higher accuracy.This will be shown later when the Analysis Settings are discussed.Workshop 2.Simulate the Crushing of an Empty Soda CanWS 2-12ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 5 Edit the Model in Mechanical.Rigid Steel Punch(moved downwards)Flexible Aluminum Soda Can(crushed)Rigid Steel Die(fixed)5.c Define the Aluminum Can properties:Stiffness Behavior=FlexibleThickness=0.00025 metersMaterial Assignment=My_Aluminum5.d Define the Punch and Die properties:Stiffness Behavior=RigidMaterial Assignment=Structural SteelWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-13ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 5 Edit the Model in Mechanical.5.e Review the Contact specificationsKeep contact definition defaults5.f Save the ProjectNote:There is no Save icon in MechanicalWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-14ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 6 Set Sizing Controls and Mesh Model6.d Orient the model to select the 8 edges that define the can circumferences(with the Left Mouse Button).Use the Ctrl key for multiple selections,as needed.6.a Select the Mesh branch 6.b Specify the Mesh Details:Physics Preference=ExplicitElement Size=0.010 meters6.c Choose the Edge selection filterRMB(anywhere)6.e With the 8 edges still highlighted,Insert(RMB anywhere on graphics screen)an Edge SizingSCSCWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-15ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 6 Set Sizing Controls and Mesh Model.6.f Specify the Edge Sizing Details:Type=Number of DivisionsNumber of Divisions=36Behavior=Hard6.g Generate the Mesh(RMB on either Mesh branch or Edge Sizing branch)RMBSCMesh viewWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-16ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 7 Define the Analysis Settings 7.a Specify the Analysis Settings:End Time=6.0e-4 secondsAutomatic Mass Scaling=YesMinimum CFL Time Step=1.0e-7 secSC7.b Set the Solve Units=mm,mg,msNote:The mm,mg,ms unit system is the most accurate in most simulations,so it is the only one currently available.Although more solver unit systems will be available in the future,any unit system in the drop-down list may be used to enter data and/or display the results.Workshop 2.Simulate the Crushing of an Empty Soda CanWS 2-17ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 7 Define the Analysis Settings.7.c Keep the remaining defaultsNote:There are multiple ways to control the erosion of an element.In this case,the element will only fail when the geometric strain reaches 150%.7.d Use the default number of data sets to save during the solution.Depending on the analysis,this number may need to be increased,but that requires additional disk space,so be judicious here.Workshop 2.Simulate the Crushing of an Empty Soda CanWS 2-18ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 8 Apply BCs and External Loads 8.a Fix the Steel Die(base):Select the Body filterInsert a Fixed Support under Explicit DynamicsSelect the steel dieApply the selectionRMBSCSCWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-19ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 8 Apply BCs and External Loads.8.b Displace the Steel PunchInsert a Displacement under Explicit DynamicsSelect the steel dieApply the selectionRMBSCSCWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-20ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 8 Apply BCs and External Loads.Note:The punch speed and abrupt change in direction are unrealistic,but sufficient for demonstration purposes.Normally,the movement would be prescribed according to a SINE wave function.8.c Specify the vertical(Y)displacement to be a Tabular load and set both the X and Z displacements to be zero.8.d Ramp the Y displacement as follows:Time=0.0 sec Y=0.0 meters Time=5e-4 sec Y=-0.060 meters Time=6e-4 sec Y=-0.030 metersWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-21ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 9 Insert Result Items to Postprocess9.a Insert a Total Deformation plot request under the Solution branch.9.b Insert an Equivalent(von-Mises)Stress plot request under the Solution branch.The rigid bodies(i.e.,the punch and die)will not show stress.RMBRMBSCSCSCSCSCSCWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-22ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 9 Insert Result Items to Postprocess.9.c Insert an Equivalent Plastic Strain plot request under the Solution branch.RMBSCSCSCNote:Even though a single time point(at the end of the run)is specified,the complete set of results can be viewed,including animations.Recall that the default output controls(20 equally spaced time points)was retained under the Analysis Settings branch.9.d Save the Project again.Workshop 2.Simulate the Crushing of an Empty Soda CanWS 2-23ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 10 Run the AUTODYN Simulation10.a Select Solver Output under Solution Information and Solve the simulation.The Solver Output shows the run statistics,including the estimated clock time to completion.Any errors or warnings are also noted.Termination due to“wrapup time reached”is expected here.SCWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-24ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 10 Run the AUTODYN Simulation.10.b Select Energy Summary under Solution Information to review the global statistics.Note the abrupt changes in kinetic energy due to the unrealistic loading scenario.TIME=5.0e-4 seconds occurs around 3200 cycles into runConstant velocity after starting from restWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-25ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 11 Review the Results11.a Select Total Deformation and Show the Elements under True Scale.The maximum deformation(-0.060 m)exceeds the punch value due to the momentum involved(i.e.,an excessive punch speed was used to reduce the required computer run time).SCWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-26ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 11 Review the Results.11.b Animate the results by setting the controls as shown below and then pressing the Animation button.For transient dynamics,the default Distributed mode is inadequate,as it linearly interpolates between saved results.The Result Sets mode is optimal,as it uses the actual saved data.To review a static result,just click on the desired Time or Value from the Tabular Data and use the RMB to pick Retrieve This Result.The given state will then be shown.RMBPick these 2 firstThen pick thisPick this to save the animationTo retrieve a given result.Workshop 2.Simulate the Crushing of an Empty Soda CanWS 2-27ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 11 Review the Results.11.c Repeat the procedure,if desired,for the von-Mises equivalent stress results.Note:No stress can develop in a rigid body.The punch and die are each condensed out to a mass at their respective centers of gravity with six DOFs active.Contact is based on the exterior surface,so a six DOF body can have a complicated contact surface.SCWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-28ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 11 Review the Results.11.d Repeat the procedure one last time for the equivalent plastic strain results.11.e.Hide the Punch and Die for a better view of the results.Per the Analysis Settings,erosion does not occur until the geometric strain is 1.50SCSCRMBWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-29ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 12 Review the Output Files12.a Pick Files under the View menu to access the Project files12.b Select Open Containing Folder via the RMB option for the AUTODYN print file(admodel.prt).RMBWorkshop 2.Simulate the Crushing of an Empty Soda CanWS 2-30ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved.February 27,2009Inventory#002665Training ManualStep 12 Review the Output Files.12.c Double click on the file admodel.prt 12.d As noted earlier,the solver units system was mm-mg-ms in order to maximize the accuracy.After the Simulation is done,the results are converted back into the current Mechanical units system.Workshop 2.Simulate the Crushing of an Empty Soda CanWS 2-31ANSYS,Inc.Proprietary 2009 ANSYS,Inc.All rights reserved