有限单元法B 实验指导书.docx

有限单元法B 实验指导书.docx

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有限单元法B实验指导书

有限单元法B实验指导书

机械科学与工程学院

机械设计及自动化系

张贵林编

二〇〇九年十一月

目录

目录2

实验0GettingStartedwithANSYS3

实验1平面结构的静力学分析4

实验2空间结构应力场分析18

实验32DPlaneStressBracketExample32

实验4aSteady-StateThermalAnalysis61

实验5aCompressibleFlowAnalysis75

附录1实验报告格式84

注：

仅实验0、1、2为8学时上机实验内容，

实验3、4、5为附加内容。

利于你获得较高成绩！

实验0GettingStartedwithANSYS

TheANSYSprogramhasmanyfinite-elementanalysiscapabilities,rangingfromasimple,linear,staticanalysistoacomplex,nonlinear,transientdynamicanalysis.TheprocessforatypicalANSYSanalysisinvolvesthreegeneraltasks:

●BuildingtheModel

●ApplyingLoadsandObtainingtheSolution

●ReviewingtheResults

0.1.1StartLMTOOLSUtility

TheLMTOOLSutilityisaWindows-onlylicenseadministrationtool.WiththeLMTOOLSutility,youcanstart,stop,andreconfigurethelicensemanager,getinformationsuchashostids,getserverstatus,andmore.

ToactivatethelauncheronWindows,choose

Start>LMTOOLSUtility

SelecttheStart/atop/RereadButton,andstarttheserver.WhentheServerStartSuccessfulappeared,youcanstarttheANSYSLauncher.

0.1.2TheANSYSLauncher

ToactivatethelauncheronWindows,choose

Start>Programs>ANSYS11.0>ANSYSProductLauncher

IfyouselectedaANSYSproduct,youcanspecify:

Workingdirectory（youcreatedonaharddisk）andJobname（youwanttoname）.ThentheANSYSGUIappeared,andyoucandoourexperimentswithGUImethodandCommandorBatchMethod.

ThestandardANSYSGUIisthedefault.ThislayoutshowstheUtilityMenu,StandardToolbar,InputWindow,ANSYSToolbar,MainMenu,GraphicsWindow,StatusArea,andOutputWindow.Youcanresizethetoolbars,theoverallsizeoftheGUI,thefont,andthecolor.

实验1平面结构的静力学分析

2.1.StaticAnalysisofaCornerBracket

2.1.1.ProblemSpecification

ApplicableANSYSProducts:

ANSYSMultiphysics,ANSYSMechanical,ANSYSStructural,ANSYSED

LevelofDifficulty:

easy

InteractiveTimeRequired:

60to90minutes

Discipline:

structural

AnalysisType:

linearstatic

ElementTypesUsed:

PLANE82

ANSYSFeaturesDemonstrated:

solidmodelingincludingprimitives,Booleanoperations,andfillets;taperedpressureload;deformedshapeandstressdisplays;listingofreactionforces;examinationofstructuralenergyerror

ApplicableHelpAvailable:

StructuralStaticAnalysisintheStructuralAnalysisGuide,PLANE82intheElementsReference.

2.1.2.ProblemDescription

Thisisasimple,singleloadstep,structuralstaticanalysisofthecorneranglebracketshownbelow.Theupperleft-handpinholeisconstrained（welded）arounditsentirecircumference,andataperedpressureloadisappliedtothebottomofthelowerright-handpinhole.TheobjectiveoftheproblemistodemonstratethetypicalANSYSanalysisprocedure.TheUSCustomarysystemofunitsisused.

2.1.2.1.Given

Thedimensionsofthecornerbracketareshownintheaccompanyingfigure.ThebracketismadeofA36steelwithaYoung’smodulusof30E6psiandPoisson’sratioof.27.

2.1.2.2.ApproachandAssumptions

Assumeplanestressforthisanalysis.Sincethebracketisthininthezdirection（1/2inchthickness）comparedtoitsxandydimensions,andsincethepressureloadactsonlyinthex-yplane,thisisavalidassumption.

Yourapproachistousesolidmodelingtogeneratethe2-Dmodelandautomaticallymeshitwithnodesandelements.（AnotheralternativeinANSYSistocreatethenodesandelementsdirectly.）

2.1.2.3.SummaryofSteps

Usetheinformationintheproblemdescriptionandthestepsbelowasaguidelineinsolvingtheproblemonyourown.

1.BuildGeometry

2.DefineMaterials

3.GenerateMesh

4.ApplyLoads

5.ObtainSolution

6.ReviewResults

7.ExittheANSYSprogram.

2.1.3.BuildGeometry

ThisisthebeginningofPreprocessing.

2.1.3.1.Step1:

Definerectangles.

ThereareseveralwaystocreatethemodelgeometrywithinANSYS,somemoreconvenientthanothers.ThefirststepistorecognizethatyoucanconstructthebracketeasilywithcombinationsofrectanglesandcirclePrimitives.

Decidewheretheoriginwillbelocatedandthendefinetherectangleandcircleprimitivesrelativetothatorigin.Thelocationoftheoriginisarbitrary.Here,usethecenteroftheupperleft-handhole.ANSYSdoesnotneedtoknowwheretheoriginis.Simplybeginbydefiningarectanglerelativetothatlocation.InANSYS,thisoriginiscalledtheglobalorigin.

1.MainMenu>Preprocessor>Modeling>Create>Areas>Rectangle>ByDimensions

2.Enterthefollowing:

X1=0（Note:

PresstheTabkeybetweenentries）

X2=6

Y1=-1

Y2=1

Applytocreatethefirstrectangle.

3.Enterthefollowing:

X1=4

X2=6

Y1=-1

Y2=-3

4.OKtocreatethesecondrectangleandclosethedialogbox.

2.1.3.2.Step2:

Changeplotcontrolsandreplot.

Theareaplotshowsbothrectangles,whichareareas,inthesamecolor.Tomoreclearlydistinguishbetweenareas,turnonareanumbersandcolors.The"PlotNumberingControls"dialogboxontheUtilityMenucontrolshowitemsaredisplayedintheGraphicsWindow.Bydefault,a"replot"isautomaticallyperformeduponexecutionofthedialogbox.Thereplotoperationwillrepeatthelastplottingoperationthatoccurred（inthiscase,anareaplot）.

1.UtilityMenu>PlotCtrls>Numbering

2.Turnonareanumbers.

3.OKtochangecontrols,closethedialogbox,andreplot.

Beforegoingtothenextstep,savetheworkyouhavedonesofar.ANSYSstoresanyinputdatainmemorytotheANSYSdatabase.Tosavethatdatabasetoafile,usetheSAVEoperation,availableasatoolontheToolbar.ANSYSnamesthedatabasefileusingtheformatjobname.db.IfyoustartedANSYSusingtheproductlauncher,youcanspecifyajobnameatthatpoint（thedefaultjobnameisfile）.YoucancheckthecurrentjobnameatanytimebychoosingUtilityMenu>List>Status>GlobalStatus.Youcanalsosavethedatabaseatspecificmilestonepointsintheanalysis（suchasafterthemodeliscomplete,orafterthemodelismeshed）bychoosingUtilityMenu>File>SaveAsandspecifyingdifferentjobnames（model.db,ormesh.db,etc.）.

Itisimportanttodoanoccasionalsavesothatifyoumakeamistake,youcanrestorethemodelfromthelastsavedstate.YourestorethemodelusingtheRESUMEoperation,alsoavailableontheToolbar.（YoucanalsofindSAVEandRESUMEontheUtilityMenu,underFile.）

4.Toolbar:

SAVE_DB.

2.1.3.3.Step3:

Changeworkingplanetopolarandcreatefirstcircle.

Thenextstepinthemodelconstructionistocreatethehalfcircleateachendofthebracket.YouwillactuallycreateafullcircleoneachendandthencombinethecirclesandrectangleswithaBoolean"add"operation（discussedinstep5.）.Tocreatethecircles,youwilluseanddisplaytheworkingplane.Youcouldhaveshowntheworkingplaneasyoucreatedtherectanglesbutitwasnotnecessary.

Beforeyoubeginhowever,first"zoomout"withintheGraphicsWindowsoyoucanseemoreofthecirclesasyoucreatethem.Youdothisusingthe"Pan-Zoom-Rotate"dialogbox,aconvenientgraphicscontrolboxyou’lluseofteninanyANSYSsession.

1.UtilityMenu>PlotCtrls>Pan,Zoom,Rotate

2.Clickonsmalldotoncetozoomout.

3.Closedialogbox.

4.UtilityMenu>WorkPlane>DisplayWorkingPlane（toggleon）

NoticetheworkingplaneoriginisimmediatelyplottedintheGraphicsWindow.ItisindicatedbytheWXandWYsymbols;rightnowcoincidentwiththeglobaloriginXandYsymbols.NextyouwillchangetheWPtypetopolar,changethesnapincrement,anddisplaythegrid.

5.UtilityMenu>WorkPlane>WPSettings

6.ClickonPolar.

7.ClickonGridandTriad.

8.Enter.1forsnapincrement.

9.OKtodefinesettingsandclosethedialogbox.

10.MainMenu>Preprocessor>Modeling>Create>Areas>Circle>SolidCircle

Besuretoreadpromptbeforepicking.

11.Pickcenterpointat:

WPX=0（inGraphicsWindowshownbelow）

WPY=0

12.Movemousetoradiusof1andclickleftbuttontocreatecircle.

13.OKtoclosepickingmenu.

14.Toolbar:

SAVE_DB.

Note

Whileyouarepositioningthecursorforpicking,the"dynamic"WPXandYvaluesaredisplayedintheSolidCircularAreadialogbox.Also,asanalternativetopicking,youcantypethesevaluesalongwiththeradiusintothedialogbox.

2.1.3.4.Step4:

Moveworkingplaneandcreatesecondcircle.

Tocreatethecircleattheotherendofthebracketinthesamemanner,youneedtofirstmovetheworkingplanetotheoriginofthecircle.ThesimplestwaytodothiswithoutenteringnumberoffsetsistomovetheWPtoanaveragekeypointlocationbypickingthekeypointsatthebottomcornersofthelower,rightrectangle.

1.UtilityMenu>WorkPlane>OffsetWPto>Keypoints

2.Pickkeypointatlowerleftcornerofrectangle.

3.Pickkeypointatlowerrightofrectangle.

4.OKtoclosepickingmenu.

5.MainMenu>Preprocessor>Modeling>Create>Areas>Circle>SolidCircle

6.Pickcenterpointat:

WPX=0

WPY=0

7.Movemousetoradiusof1andclickleftbuttontocreatecircle.

8.OKtoclosepickingmenu.

9.Toolbar:

SAVE_DB.

2.1.3.5.Step5:

Addareas.

Nowthattheappropriatepiecesofthemodelaredefined（rectanglesandcircles）,youneedtoaddthemtogethersothemodelbecomesonecontinuouspiece.YoudothiswiththeBooleanaddoperationforareas.

1.MainMenu>Preprocessor>Modeling>Operate>Booleans>Add>Areas

2.PickAllforallareastobeadded.

3.Toolbar:

SAVE_DB.

2.1.3.6.Step6:

Createlinefillet.

1.UtilityMenu>PlotCtrls>Numbering

2.Turnonlinenumbering.

3.OKtochangecontrols,closethedialogbox,andautomaticallyreplot.

4.UtilityMenu>WorkPlane>DisplayWorkingPlane（toggleoff）

5.MainMenu>Preprocessor>