R212ABAQUS资料IABSW03QNonlinearStaticsWord文档格式.docx

R212ABAQUS资料IABSW03QNonlinearStaticsWord文档格式.docx

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Introduction

InthisworkshopyouwillmodeltheplateshowninFigureW3–1.Itisskewedat30°

totheglobalX-axis,built-inatoneend,andconstrainedtomoveonrailsparalleltotheplateaxisattheotherend.Youwilldeterminethemidspandeflectionwhentheplatecarriesauniformpressure.Youwillmodifythemodeltoincludealternatenodalandmaterialdirectionsaswellasnonlineareffects.

Figure 

W3–1.Sketchofskewedplate

Preliminaries

1.Entertheworkingdirectoryforthisworkshop

../abaqus_solvers/interactive/skew

2.Runthescriptws_solver_skew_plate.pyusingthefollowingcommand:

abaquscaestartup=ws_solver_skew_plate.py.

TheabovecommandcreatesanAbaqus/CAEdatabasenamedSkewPlate.caeinthecurrentdirectory.Amodelnamedlinearincludesthegeometry,meshandmaterialdefinitionsfortheplate.Youwillfirstaddthenecessarydatatocompletethelinearanalysismodel.Youwilllaterperformthesimulationconsideringbothgeometricallyandmaterialnonlineareffects.Inasubsequentworkshoparestartanalysiswillbeperformedtostudytheunloadingoftheplate.

Definingthelocalmaterialdirections

Theorientationofthestructureintheglobalcoordinatesystemisshownin

FigureW3–1.TheglobalCartesiancoordinatesystemdefinesthedefaultmaterialdirections,buttheplateisskewedrelativetothissystem.Itwillnotbeeasytointerprettheresultsofthesimulationifyouusethedefaultmaterialdirectionsbecausethedirectstressinthematerial1-direction（i.e.,globalX-direction）,σ11,willcontaincontributionsfromboththeaxialstress,producedbythebendingoftheplate,andthestresstransversetotheaxisoftheplate.Itwillbeeasiertointerprettheresultsifthematerialdirectionsarealignedwiththeaxisoftheplateandthetransversedirection.Therefore,alocalrectangularcoordinatesystemisneededinwhichthelocalx-directionliesalongtheaxisoftheplate（i.e.,at30º

totheglobalX-axis）andthelocaly-directionisalsointheplaneoftheplate.

Youwilldefinethedatumcoordinatesystem（CSYS）andthenassignthematerialorientation.

1.SwitchtothePropertymoduleanddefinearectangulardatumcoordinatesystemasshowninFigureW3–2usingtheCreateDatumCSYS:

2Linestool

.

a.Notethesmallblacktrianglesatthebaseofthetoolboxicons.Thesetrianglesindicatethepresenceofhiddeniconsthatcanberevealed.ClicktheCreateDatumCSYS:

3Pointstool

butdonotreleasethemousebutton.Whenadditionaliconsappear,releasethemousebutton.

b.SelecttheCreateDatumCSYS:

.Itappearsinthetoolboxwithawhitebackgroundindicatingthatyouselectedit.

c.IntheCreateDatumCSYSdialogbox,namethedatumCSYSSkew,selecttheRectangularcoordinatesystemtype,andclickContinue.MakethenexttwoselectionsasindicatedinFigureW3–2.

W3–2.Datumcoordinatesystemusedtodefinelocaldirections

2.Assignthematerialorientationstotheplate.

a.Inthetoolbox,clicktheAssignMaterialOrientationtool

.

b.Selecttheentirepartastheregiontobeassignedalocalmaterialorientation.

c.Clickmousebutton2intheviewportorclickDoneinthepromptareatoconfirmtheselection.

d.ClickDatumCSYSListinthepromptarea.

e.IntheDatumCSYSListdialogbox,selectskewandclickOK.Inthematerialorientationeditor,selectAxis3forthedirectionoftheapproximateshellnormal.Noadditionalrotationisneededaboutthisaxis.

f.ClickOKtoconfirmtheinput.

Tip:

Toverifythatthelocalmaterialdirectionshavebeenassignedcorrectly,selectTools→Queryfromthemainmenubarandperformapropertyqueryonthematerialorientations.

Oncetheparthasbeenmeshedandelementshavebeencreatedinthemodel,allelementvariableswillbedefinedinthislocalcoordinatesystem.

Prescribingboundaryconditionsandappliedloads

AsshowninFigureW3–1,theleftendoftheplateiscompletelyfixed;

therightendisconstrainedtomoveonrailsthatareparalleltotheaxisoftheplate.Sincethelatterboundaryconditiondirectiondoesnotcoincidewiththeglobalaxes,youmustdefinealocalcoordinatesystemthathasanaxisalignedwiththeplate.Youcanusethedatumcoordinatesystemthatyoucreatedearliertodefinethelocaldirections.

1.IntheModelTree,double-clicktheBCscontaineranddefineaDisplacement/RotationmechanicalboundaryconditionnamedRailboundaryconditionintheApplyPressurestep.

Inthisexampleyouwillassignboundaryconditionstosetsratherthantoregionsselecteddirectlyintheviewport.Thus,whenpromptedfortheregionstowhichtheboundaryconditionwillbeapplied,clickSetsinthepromptareaoftheviewport.

2.FromtheRegionSelectiondialogboxthatappears,selectthesetPlate-1.EndB.ToggleonHighlightselectionsinviewporttomakesurethecorrectsetisselected.Therightedgeoftheplateshouldbehighlighted.ClickContinue.

3.IntheEditBoundaryConditiondialogbox,click

tospecifythelocalcoordinatesysteminwhichtheboundaryconditionwillbeapplied.Intheviewport,selectthedatumCSYSPlate-1.Skew.Thelocalx-directionisalignedwiththeplateaxis.

NotethatPlate-1.Skewistheassembly-leveldatumCSYSgeneratedbythepart-leveldatumCSYSSkew.

4.IntheEditBoundaryConditiondialogbox,fixalldegreesoffreedomexceptforU1bytogglingthemonandenteringavalueof0foreach.

Therightedgeoftheplateisnowconstrainedtomoveonlyinthedirectionoftheplateaxis.Oncetheplatehasbeenmeshedandnodeshavebeengeneratedinthemodel,allprintednodaloutputquantitiesassociatedwiththisregion（displacements,velocities,reactionforces,etc.）willbewritteninthislocalcoordinatesystem.

5.CreateanotherboundaryconditionnamedFixleftendtofixalldegreesoffreedomattheleftedgeoftheplate（setPlate-1.EndA）.Usethedefaultglobaldirectionsforthisboundarycondition.

6.DefineauniformpressureloadnamedPressureacrossthetopoftheshellintheApplyPressurestep.Selectbothregionsofthepartusing[Shift]+Click,andchoosethetopsideoftheshell（Brown）asthesurfacetowhichthepressureloadwillbeapplied.Youmayneedtorotatetheviewtomoreclearlydistinguishthetopsideoftheplate.Specifyaloadmagnitudeof2.0E4Pa.

Runningthejobandpostprocessingtheresults

1.CreateajobnamedSkewPlatewiththefollowingdescription:

LinearElasticSkewPlate,20kPaLoad.

2.Saveyourmodeldatabasefile.

3.Submitthejobforanalysisandmonitorthesolutionprogress.

Whentheanalysisiscomplete,usethefollowingproceduretopostprocesstheanalysisresults.

4.IntheModelTree,clickmousebutton3onthejobSkewPlateandselectResultsfromthemenuthatappearstoopenthefileSkewPlate.odbintheVisualizationmodule.

5.ClickthePlotDeformedShapetool

toplotthedeformedshape.

6.UsethetheQueryinformationtool

toprobethevalueofthemidspandeformation.

a.IntheQuerydialogbox,selectProbevaluesintheVisualizationModuleQueriesfield.

b.Changethedisplayedfieldvariabletothedisplacementalongthe3-direction.IntheProbeValuesdialogbox,click

tochangethedefaultfieldoutputvariabletoU3.IntheFieldOutputdialogboxthatappears,selectUastheoutputvariableandU3asthecomponentandclickOK.

c.IntheProbeValuesdialogbox,selectNodesastheitemtoprobe.

d.Clickonanode（asindicatedinFigureW3–3）alongthemidespantoprobeitsdisplacementalongthe3-direction.Enterthisvalueinthe“Linear”columnofTableW3–1.

FigureW3–3.Midspannode

Addinggeometricnonlinearity

Nowperformthesimulationconsideringgeometricallynonlineareffects.Copythemodelnamedlineartoanewmodelnamednonlinear.Youwilladdgeometricnonlinearityintothemodelnonlinear;

thechangesrequiredforthismodelaredescribednext.

7.IntheModelTree,expandtheStepscontaineranddouble-clickApplyPressuretoeditthestepdefinition.

a.IntheBasictabbedpageoftheEditStepdialogbox,toggleonNlgeomtoincludegeometricnonlinearityeffectsandsetthetimeperiodforthestepto1.0.

b.IntheIncrementationtabbedpage,settheinitialincrementsizeto0.1.

Notethatthedefaultmaximumnumberofincrementsis100;

Abaqusmayusefewerincrementsthanthisupperlimit,butitwillstoptheanalysisifitneedsmore.

Youmaywishtochangethedescriptionofthesteptoreflectthatitisnowanonlinearanalysisstep.

8.CreateajobnamedNlSkewPlateforthemodelnonlinearandgiveitthedescriptionNonlinearElasticSkewPlate.Saveyourmodeldatabasefile.

9.Submitthejobforanalysisandmonitorthesolutionprogress.

TheJobMonitorisparticularlyusefulinnonlinearanalyses.Itgivesabriefsummaryoftheautomatictimeincrementationusedintheanalysisforeachincrement.Theinformationiswrittenassoonastheincrementiscompleted,soyoucanmonitortheanalysisasitisrunning.Thisfacilityisusefulinlarge,complexproblems.TheinformationgivenintheJobMonitoristhesameasthatgiveninthestatusfile（NlSkewPlate.sta）.

10.Whenthejobisc