ANSYS 英文实用培训教程.docx

ANSYS 英文实用培训教程.docx

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ANSYS英文实用培训教程

ENSC895Assignment3Tutorial

Lastupdatedon:

Feb25th,2013

Inthislab,studentswilllearnthebasictechniquesofFEAanalysis.AstaticstructuralanalysiswillbeperformedonaracksystemusingANSYSworkbench.Geometrysimplificationwillbeintroducedtothestudents.Severalmeshtechniqueswillbebrieflyintroducedtothestudents.Howevermappedmeshingisthecorelearningobjective.Thelabwillalsointroducethestudentswithbasicpost-processingtechniquesneededtointerprettheanalysisresults.

Learningobjectives:

Mid-surfacetechnique:

studentshavetolearnhowtoextractthemid-surfacetoproducehighqualitymesh.Theruleofthumbisthataslongasthethicknessis1/5ofthewidthorlength,thebodycanbesimplifiedtosurfacebody.Surfacebodyusesplaneorshellelementssuchassolid186orshell181.However,thestudentsdon’thavetoworryaboutwhichelementstoselectfromsinceANSYSwillautomaticallyselectthem.Therearetwowaystoextractmid-surfaces,seetutorialsfordetails.

Learnbasicdefeaturingtechniques:

Certainunnecessarydetailsshouldberemovedfromtheanalysisinordertoobtainbettermeshingeffects.Forexample,filletsandchamfersthatdon’tplaymajorrolesinFEAanalysisinmanycasescanbeignoredtogeneratebetterlocalmesh.Studentscandoacomparativestudytoseetheeffectiftimepermits.

Numberofdivisionspercycle:

Accordingtocertainindustrystandard,thecirclehastobedividedintoatleast12elements.NormallyANSYSversion14.5willautomaticallydetectanddividethecircleto12elements.Ifnot,onecandoitmanually.Seedetailsfromthetutorials.

BondedcontactwithMPCalgorithm:

Inthisassignmentallcontactswillbeautomaticallygenerated.Butsomegeometricalpreprocessingisneededinordertohaveeffectivecontacts.

Convergencestudy:

Ameshindependentstudyshouldbeperformedonthestructuretoseehowmeshqualitiescanaffectthefinalresults.Withtheimprovementofmeshthestressvalueshouldapproachasteadystatemeaningitsvalueshouldbewithin5%.

Checkreactions:

LearnhowtocheckthereactionsafteraFEAanalysishasbeenperformed.Forexample,three1000Nforcesareaddedondifferentlevelandthereactionatitsboundaryshouldbebalancedforthestructuretobeinequilibrium.

EnteringANSYS

DoubleclickonANSYSworkbench

fromdesktop.

OnceyouhaveenteredANSYSworkbenchdragStaticStructuralfromtheAnalysisSystemtotheblankareacalledontheright.ThendoubleclickonGeometrytoaccessDM（DesignModeler）.

SelectMillimeterasthedesiredlengthunit.

BriefIntroductiontosomefunctionsinDM（DesignModeler）

ThefunctionsbelowintheredboxesarethecommonlyusedfunctionsinANSYSpreprocessing.Thesefunctionsareprimarilyusedforgeometrysimplifications.Geometrysimplificationisoneofthemostimportanttasksinpreprocessing.ProperlysimplifiedgeometrycangreatlyimprovethequalityofmeshandthusresultspredictedbytheFEAanalysis.

Mid-Surface:

Itisusedtoextractthemiddle-surface.Whenabodycanbeconsideredasaplateorshell（itsshortestdimensionisthe1/5ofotherdimensions）,normallyitshouldbesimplified.I

Thin/Surface:

ThisisabackupchoiceforMid-SurfaceasMid-Surfacefailstoworksometimes.Itcanalsobeusedtoachieveothertaskssuchasformingacavity.

FaceDelete:

Thisisusedtodeleteunnecessaryfacesinordertoimprovemeshquality.Unnecessarydetailsoftenimpedeonefromproducinghighqualitymesh.

EdgeDelete:

SameasFaceDelete,butitisforoperationsonedges.

NewPlane:

Userscanestablishnewplanesforallkindsofpurposes.However,inthisexercise,itisprimarilyusedasreferenceplaneforcutting/slicing.

Slice:

Thepurposeofslicingoperationismultiple.InthisanalysisSliceoperationsareneededinordertogeneratemoremappableregions.Withmappableregions,thequalityofmeshshouldbehigher.

Mappableregions:

Mappableregionsarethosesurfaceareasonwhichmappedmeshcanbegenerated.Mappedmeshestypicalhavehighqualityandeffectiveness.Areascoveredbymappedmeshtypicallylooksmoreregularintermsoftheshapeofthemesh.Usemappedsurfacemeshwheneverapplicable.

Doubleclickonengineeringdata.

First,clickonEngineeringDataSources

.ThenclickonGeneralMaterialstoseealistofcommonlyusedengineeringmaterials.ThenmoveontoOutlineofgeneralmaterialsandclickontheaddsign

.AddAluminumAlloyforlateruse.（Steelisdefaultedmaterialwhichyoudon’thavetoadd）GobacktotheDM.

DoubleclickonGeometrytoaccessANSYSDM.

ImportgeometryintoANSYSworkbench:

ClickonfileandselectImportExternalGeometryFile.Thelocationoftheparasolidgeometry（x_t）willbegiventoyou.

Thegeometrywilllooklikethisifitisimportedcorrectly.

ExtractingMiddleSurfaces

Mid-surfacecommandwillbeusedtoextractmiddlesurfaceofthesheetmetal.Selectfacepairsbyclickingonthefrontandbacksideofthecolumnbar.Aftersuccessfullyselected,itwillbehighlightedinpurple.

However,inordertoselectasmanylegitimatesurfacebodiesaspossible,onecanexploititsauto-selectioncapabilitybychangingtheselectionmethodfrommanualtoautomatic.Noteyoushouldclickon“Findingsurfacepairsnow”onceinorderforthistowork.Thenallavailablesurfacebodieswillbeselectedallatoncewhichwillsaveyouconsiderableamountoftime.

ThereareoccasionsthatMid-surfacewillfailtoworkduetothecomplexityofthegeometry.Fortunately,thereisanothermethodwecanuseinordertobypassthisissue.Thin/SurfacecanbeusedasatooltoextractsurfacebodywhileMid-surfacefailstowork.Clickonthesurfacebodieswhileholdingthectrlkeythisallowsyoutoselectasmanysurfaceasyoumightneed.ChangetheSelectionTypetoFacestoKeepasindicatedbelow.Sincethebottomplateshavethicknessof3mm,inordertoserveasmiddlesurfacesthefaceoffsetshouldbehalfofitwhichis1.5mm.

Defeaturing

NormallygeometriesimportedfromCADsoftwarearetoocomplicatedandhavetoomanydetailstocapture.AsaFEAanalyst,youhavetoknowhowtoremoveunnecessarydetailsasitwillimprovethequalityofmesh.

Surface-deleteisatechniquetodeleteunwantedsurfaces.Forexample,inmanycasesfilletsandchamfersdon’tplayamajorroleinstressanalysisandthuscanbedeleted.

Edge-deleteissimilartoSurface-deleteinwhichitremovesunnecessaryedgesinsteadofsurfaces.

Settingupthethickness:

WhenThin/Surfaceisusedtoextractmiddlesurfaceitwillloseinformationonitsthickness.GotoANSYSDesignSimulation（DS）bydoubleclickingonModel.All“part3”arebottomholdingplates,itshouldbenotedthat“part3”arewithquestionmarksbeforesetup.Selectallof“part3”andsetthethicknessto3mm.

Thenextstepisquitecrucialforgeneratinghighqualitymesh.Inordertoproducehighqualitymesh,thegeometryshouldbemadetobemappable（SometimesSweepableinthecaseofsolids）.Inordertohaveasmanymappableregionaspossible,Slicefunctionisusedtoseparatethegeometrytosimplershapesandthusmorelikelytobemappable.

Slicecanbeperformedundertheconditionthatthegeometryorapartofthatgeometryisfrozen.WhilethegeometryisfirstimportedtotheDM,itisdefaultedtobefrozen.Thereforeslicecanbeappliedtoeachbodydirectly.

Thereareseveralslicingmethods.Commonlyusedinthisexercisearetwo:

1）SlicebySurface;2）Slicebyplane.

SlicebySurface:

Selectthesurfacethatyouwanttouseasatoolsurface.ClickonSliceandchangeSliceTypetoSlicebySurfaceandapply.Asindicatedbelow,thegeometrywillbeslicedaboutthetoplevelsurface.Dothisrepeatedlyfor3differentlevels.

SlicebyPlane:

Inorderforthisslicingmethodtowork,anewcoordinatesystemneedstobeconstructed.Clickon

tocreateanewcoordinatesystem.Thenewcoordinatesystemwillbeestablishedonthecorner.

Inorderforslicingplanetowork,onehastore-orientthecoordinatesystemsuchthattheredandgreenaxisformingtheplaneofslicing.Inotherwords,slicingplanewillbeperpendiculartotheblueaxis.

Thenewcoordinatesystemwillbeshown.ChangeTypetoFromPointandNormal.Aspoint-normalmethodwillbethemostconvenientwaytoconstructacoordinate.

Basepointwillbetheoriginofthecoordinatesystemandclickonthevertexasindicatedbelow.ClickonNormalDefinedbyandthengotogeometrytoclickanaxisthatyouwanttospecifyasthenormalaxis.Abigredarrowwillbeshowninthescreentoindicatethedirectionyourselectednormalline.Itdoesn’tmatterastowhatdirectionthebluearrowispointingat,aslongastheredandgreenaxesformtheplaneofcuttingitshouldbeworkingcorrectly.

Thenextstepistousethecoordinatesystemthatyoujustcreatedasareferencetoslicetheplane.

SelectSlicefunctionandchoosetheSliceTypeasSlicebyPlanethistime.ChangetheBasePlanetotheplanethatyouwanttosliceabout.（Normallyifyouhavejustcreatedacoordinatesystem,itwillbedefaultedtoBasePlane.Clickongeneratetoseetheeffect（youcanpressF5aswell）.

Createacoordinatesystemagainforanothercornerthistime.Justrepeattheproceduredescribedaboveuntilall4sideshavebeencovered.

Andthenuseslicebasedonthecoordinatesystemjustcreated.

Thisiswhatitlookslikewhenyouhaveslicedtwosides.

If4sidesareslicescorrectly,youshouldgeometryshouldresembletheoneshownbelow.

Createanewcoordinatesystemasshown.

Slicebasedonthecoordinatejustcreated.

Ifyouhavedoneit