appendix_e-The Essence of Result Post-Processing

TheEssenceofResultPost-ProcessingMSC.Nastran120ExerciseWorkbookE-1APPENDIXEObjectives:■Manuallycreatethegeometryforthetensioncouponusingthegivendimensionsthenapplyfiniteelements.■Manuallydefinematerialandelementproperties.■Applysymmetricboundaryconstraints.■Applyedgepressuretomodel.■RuntheanalysisandreadtheresultsbackintoMSC.Patran.■GenerateafringeplotofXstresstensorandcompareresults.E-2MSC.Nastran120ExerciseWorkbookAPPENDIXETheEssenceofResultPost-ProcessingMSC.Nastran120ExerciseWorkbookE-3ModelDescription:FigureE.1isaschematicofaplatewithacircularholeatthecenter.Thedimensionsandloadsareindicated.Thefiniteelementmodelwillbesimplifiedbycreatingthe1/4tensioncouponmodelwithtwosimplesurfacesasshowninFigureE.2.Theplateis0.125inchesthick;thereforeitwillbemodeledwithshellelements.ThetensioncouponwillhavethepropertiesofTableE.1.TheresultingfiniteelementmodelwillhaveX-andY-symmetryconstraintswithanadditionalconstraintfortranslationintheZ-direction.Theuniformedgepressureloadof100psiwillbeappliedtotherightedge.SincethePatranedgepressureconventionisintermsoflb/in,100psimustbeconvertedtoarunningloadbymultiplyingthepressurebythethicknessoftheplate.TableE.1-TensionCouponPropertiesElasticModulus:10E+06psiPoissonRatio0.3PlateThickness:0.125in100psi10.”4.”XYZ1.”FigureE.1-PlatewithCircularHole100psiXYZ1.”2.”5.”FigureE.2-SimplifiedModelwithDimensions12E-4MSC.Nastran120ExerciseWorkbookSuggestedExerciseSteps:■Createthenecessarycurvesandsurfacesofthetensioncoupongeometryandmeshthegeometrytocreateafiniteelementmodel.■Definesymmetricboundaryconstraintsandapplyauniformpressuretooneedge(TENSION_LOAD).■Definematerial(MAT_1)andelementproperties(PSHELL).■PreparethemodelforaLinearStaticAnalysis.■GenerateandsubmitaninputfiletoMSC.Nastran.■Generateafringeplotofσxx.■Reviewtheresults.APPENDIXETheEssenceofResultPost-ProcessingMSC.Nastran120ExerciseWorkbookE-5ExerciseProcedure:1.Openanewdatabasecalledappendix_e.db.IntheNewModelPreferenceformsetthefollowing:Createthenecessarygeometryfortheplatemodel.NOTE:Wheneverpossible,toggleoffthe❑AutoExecuteoptionbyleftclickingthecheckbox.2.Constructcirculararcstorepresenttheoutlineofthemodel.BecausethemappedsurfacesinMSC.Patrancanhaveupto4edges,thearcwillbecreatedin2steps.◆File/New...NewDatabaseNameappendix_EOKTolerance◆DefaultAnalysiscode:MSC/NASTRANOK◆GeometryAction:CreateObject:CurveMethod:2DArcAnglesRadius1.0StartAngle0.0EndAngle45.0ApplyRadius1.0StartAngle45.0EndAngle90.0ApplyE-6MSC.Nastran120ExerciseWorkbook3.Referringtothemodeldimensions(seeFigureE.2),theouteredgesofthegeometryarecreatedthroughthefollowingsteps:Firstthetopright.Tocreatethetopedge:4.Createtwosurfacesusingthecurvesmadeintheprevioussteps.FigureE.3-SurfaceandCurveLocations◆GeometryAction:CreateObject:CurveMethod:XYZVectorCoordinatesList0,2,0OriginCoordinatesList[5,0,0]ApplyVectorCoordinatesList-5,0,0OriginCoordinatesList[5,2,0]ApplyCurve4Surface2Curve3Curve1Surface1Curve2APPENDIXETheEssenceofResultPost-ProcessingMSC.Nastran120ExerciseWorkbookE-7Completethesurfacemodel.5.CreateaFiniteElementModelbymeshingthesurface.Itisessentialtoknowthedirectionofeachofthecurvesandlines.Thedirectionwilldeterminethebiasratio(L2/L1)ofthemeshseeds.Insteps2to4,thegeometryofthismodelwascreatedsothatthedirectionofthelines,curvesandsurfacescoincidewithFigureE.4.Simplyfollowingthenextstepwillindicatethecurvesandlinesdirections.FigureE.4◆GeometryAction:CreateObject:SurfaceMethod:CurveStartingCurveList:Curve1EndingCurveList:Curve3ApplyStartingCurveList:Curve2EndingCurveList:Curve4Apply123412a)CurveandLineDirectionsb)MeshSeedsandBiasRatio6elem1:43elem1:16elem4:1E-8MSC.Nastran120ExerciseWorkbookFirsttheelementswithmeshseedratios.Changethebiasratio(L2/L1).Finally,theuniformmeshseed.◆FiniteElementsAction:CreateObject:MeshSeedType:OneWayBias◆NumElemsandL2/L1Number=6L2/L1=4CurveListSurface1.1(Selectthebottomedge)ApplyNumber=6L2/L1=0.25CurveListCurve2(Selectthetophalfofarc)Apply◆FiniteElementsAction:CreateObject:MeshSeedType:Uniform◆NumElemsandL2/L1Number=3CurveListCurve1(Selectthebottomhalfofarc)ApplyAPPENDIXETheEssenceofResultPost-ProcessingMSC.Nastran120ExerciseWorkbookE-9Meshthesurface.Beforecontinuing,equivalencetheentiremodeltodeleteanyduplicatenodescreatedwhenmeshing.Themodelshouldappearasbelow.FigureE.5-CompletedModelwithFiniteElementMesh.◆FiniteElementsAction:CreateObject:MeshType:Surface◆IsomeshSurfaceListSurface1,2Apply◆FiniteElementsAction:EquivalenceObject:AllType:ToleranceCubeApplyE-10MSC.Nastran120ExerciseWorkbook6.Creatematerialpropertiesfortheplate.7.Defineelementproperties.8.ApplytheboundaryconditionstothemodelusingLoads/BCs.Thismodelwillhavethreedifferentcontraintssets.◆MaterialsAction:CreateObject:IsotropicMethod:ManualInputMaterialNamemat_1InputProperties...ElasticModulus=10E6PoissonRatio=0.3OKApply◆PropertiesAction:CreateDimension:2DType:ShellPropertySetNameplateInputProperties...MaterialNamem:mat_1Thickness0.125OKSelectMembersSurface1,2AddApplyAPPENDIXETheEssenceofResultPost-ProcessingMSC.Nastran120ExerciseWorkbookE-11FigureE.6-BoundaryConditi