workbench动力学分析实例教案.pptx

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1、会计学1workbench动力学分析实例动力学分析实例Workshop Goal and Procedure Goal:Crush an aluminum beverage can and allow Crush an aluminum beverage can and allow it to“springback”it to“springback”Procedure:Create an Explicit Dynamics(ANSYS)Create an Explicit Dynamics(ANSYS)Analysis System ProjectAnalysis System Project

2、Select the units system and define the Select the units system and define the material propertiesmaterial propertiesImport,modify,and mesh the soda can Import,modify,and mesh the soda can geometrygeometryDefine analysis settings,boundary Define analysis settings,boundary conditions,and external load

3、sconditions,and external loadsInitiate the solution(AUTODYN-STR)Initiate the solution(AUTODYN-STR)and review the resultsand review the results第1页/共37页Step 1 Create the Project SchematicStart ANSYS Workbench and follow the sequenced steps using the abbreviations shown below:n nDCDC=Double ClickDouble

4、 Click with Left Mouse with Left Mouse ButtonButtonn nSCSC=Single ClickSingle Click with Left Mouse with Left Mouse ButtonButtonn nRMBRMB=Right Mouse ButtonRight Mouse Button Selection Selectionn nD&DD&D=Drag and DropDrag and Drop=Hold Left =Hold Left Mouse Button down on item while Mouse Button dow

5、n on item while dragging it to new location and then dragging it to new location and then release it(i.e.,Copy or Move)release it(i.e.,Copy or Move)DC1.Create an ANSYS Explicit Dynamics Analysis System Project第2页/共37页Step 2 Specify the Project Units2.a Select MKS for the Project Units from the Units

6、 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).第3页/

7、共37页Step 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

8、 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.DC第4页/共37页DCDCDCStep 3 Define Engineering Data Material.SC3.e Add the following Physical Properties to the material definition:n nDensityDensityn

9、nIsotropic ElasticityIsotropic Elasticityn nBilinear Isotropic Bilinear Isotropic HardeningHardening3.d Make sure the new material is active in order to define its properties第5页/共37页Step 3 Define Engineering Data Material.3.f Enter the following values:Density=Density=27102710 kg kg m-3m-3Youngs Mod

10、ulus=Youngs Modulus=7e107e10 Pa PaPoissons Ratio=Poissons Ratio=0.300.30Yield Strength=Yield Strength=2.9e82.9e8 Pa PaTangent Modulus=Tangent Modulus=0.00.0 Pa PaSince the material is sufficiently defined,the blue question marks and yellow fields are no longer present in the data table.Note:The resu

11、lting stress-strain curve is elastic perfectly plastic.No strain hardening can develop.第6页/共37页Step 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_so

12、da_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.第7页/共37页Step 4 Import and Modify the Geometry4.c Workbench has now identified the geometry file(note green c

13、heckmark 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

14、 11.0 SP1 geometry file named:“soda_can_filled_110.agdb”RMBSC第8页/共37页Step 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 Proj

15、ect via the DM“Save”icon.第9页/共37页Step 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

16、 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.

17、第10页/共37页Step 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:Sti

18、ffness Behavior=RigidMaterial Assignment=Structural Steel第11页/共37页Step 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 Mechanical第12页/共37页Step 6 Set Sizing Controls and Mesh Model6.d Orient the mode

19、l 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 W

20、ith the 8 edges still highlighted,Insert(RMB anywhere on graphics screen)an Edge SizingSCSC第13页/共37页Step 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

21、branch)RMBSCMesh view第14页/共37页Step 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 o

22、nly 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.第15页/共37页Step 7 Define the Analysis Settings.7.c Keep the remaining defaultsNote:There are multiple ways to control

23、 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.第1

24、6页/共37页Step 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 selectionRMBSCSC第17页/共37页Step 8 Apply BCs and External Loads.8.b Displace the Steel PunchInsert a Displacement under Explicit Dynam

25、icsSelect the steel dieApply the selectionRMBSCSC第18页/共37页Step 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 vert

26、ical(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 meters第19页/共37页Step 9 Insert Result Items to Postprocess9.a Insert a Total Deformation plot

27、 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.RMBRMBSCSCSCSCSCSC第20页/共37页Step 9 Insert Result Items to Postprocess.9.c Insert an Equivalent Plastic Strain plot request u

28、nder 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

29、Project again.第21页/共37页Step 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 reac

30、hed”is expected here.SC第22页/共37页Step 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 ve

31、locity after starting from rest第23页/共37页Step 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

32、).SC第24页/共37页Step 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 use

33、s 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.第25页/共37页Step 1

34、1 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

35、a six DOF body can have a complicated contact surface.SC第26页/共37页Step 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 geomet

36、ric strain is 1.50SCSCRMB第27页/共37页Step 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).RMB第28页/共37页Step 12 Review the Output Files.12.c Double click on the file admo

37、del.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.第29页/共37页Step 12 Review the Output Files.12.e The AUTODYN print file also contains the Material Su

38、mmary information and run statistics.The Energy and Momentum are shown on both a material basis and a Part basis(shown here).第30页/共37页Step 12 Review the Output Files.12.f The Energy and Momentum Balance,Mass Scaling,and Run Times are also included in the admodel.prt file.12.g No mass was added to th

39、e model,since the time steps were all above the Minimum CFL Time Step of 1.0e-7 sec set in Step 7.a under Analysis Settings第31页/共37页Step 12 Review the Output Files.12.h Close the admodel.prt file and review the setup.log file in the same directory(F:exp_dynsoda_canempty_soda_can_filesdp0SYSMECH).12.

40、i The setup.log file contains the information pertaining to the transfer of data from the Explicit Dynamics(ANSYS)Analysis System to the AUTODYN Cycle Zero file,which is then run by the AUTODYN solver.12.j Close the file and return to the Mechanical window(i.e.,view the model itself again).第32页/共37页

41、Step 13 Generate a Report 13.a Click on the Solution branch in the Project tree and then click on the Report Preview tab at the bottom of graphics window.ANSYS does the rest!It will now automatically generate a report by going through the entire tree and summarizing the model and the results.第33页/共3

42、7页Step 13 Generate a Report.13.b The model properties are summarized,including volume,mass,centroid,and moment of inertia properties.13.c Loading information is also shown in clear table format.第34页/共37页Step 13 Generate a Report.13.d Even the energy plots are conveniently assembled into the report.第35页/共37页Step 13 Generate a Report.13.e The results data is shown.13.f Finally,SAVE the model and exit ANSYS.第36页/共37页