机械毕业设计英文外文翻译5CAE的技术Word格式文档下载.docx

机械毕业设计英文外文翻译5CAE的技术Word格式文档下载.docx

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slargestfiniteelementanalysissoftwareANSYS,oneoftheUnitedStatesdevelopeditwithmostCADsoftwareinterfacefordatasharingandexchange,suchasPro/Engineer,NASTRAN,Alogor,I-DEAS,AutoCAD,aremodernAdvancedCAEproductdesigntools.

ANSYSfiniteelementpackageisamulti-purposefiniteelementmethodforcomputerdesignprogram,canbeusedtosolvethestructure,fluid,electricity,electromagneticfieldsandcollisionissues.Soitcanbeappliedtothefollowingindustries:

aerospace,automotive,biomedical,bridges,construction,electronics,heavymachinery,micro-electromechanicalsystems,sportsequipment,etc..

FiniteElementAnalysis（FEA，FiniteElementAnalysis）ofthebasicconceptistore-placetherelativelysimpleproblemtosolvecomplexproblemslater.Asitwillsolvethedo-mainiscomposedofmanysmall-calledfiniteelementsubdomaininterconnectioncompone-nts，assumingthateachunitofanappropriate（relativelysimple）approximatesolution，andthenderivedthegeneralsolutionofthedomainsatisfytheconditions（suchasbalancedcon-ditions），thusthesolutionoftheproblem.Thissolutionisnotexactsolutions，butappro-ximatesolution，sincetheactualproblemisrelativelysimpletoreplacetheproblem.Sincemostpracticalproblemsitisdifficulttobeaccuratesolution，whilefiniteelementisnotonlyhighaccuracybutalsotoadapttoavarietyofcomplexshapes，therebybecominganeffectivemeansofengineeringanalysis.

FEMtogetherthosewhoareabletoexpresstheactualdomainforthediscreteelement.Theconceptofthefiniteelementasearlyasseveralcenturiesagoandhavebeenapplied，forexample，polygon（afinitenumberofstraight-lineunit）togetclosetocirclethecir-cumferenceofacircle，butasawaytobemade，itisthemostrecentmatter.Finiteele-mentmethodwasoriginallyknownasthematrixapproximationmethod，thestructuralstrengthofaircraftusedinthecalculation，andbecauseofitsconvenience，practicalityandeffectivenessarisingfromresearchscientiststoengageinmechanicalinterest.Throughtheeffortsofjustafewdecades，withtherapiddevelopmentofcomputertechnologyandthepopularityofthefiniteelementmethodinstructuralengineeringfromtheintensityoftherapidanalysisextendedtoalmostallareasofscienceandtechnology，becomearichandcolorful，practicalandefficientapplicationofawiderangeofnumericalanalysis.

Finiteelementmethodwithothermethodsofsolvingtheboundaryvalueproblemsimil-artothefundamentaldifferenceisthattheapproximationofitislimitedtorelativelysmallsub-domain.60Intheearly20thcenturystructurewasfirstproposedtheconceptofthefiniteelementcalculationofClough（Clough），Professorvividlydescribesas:

"

Thefiniteelementmethod+=RayleighRitzmethodpiecewisefunction"

，thatis，thefiniteelementmethodistheRayleighRitzmethodalocalizedsituation.Differentfromthesolutionof（oftendifficult）tosatisfytheboundaryconditionsofthedefinitionofdomainfunctiontoallowtheRayleighRitzmethod，finiteelementmethodwillbedefinedinasimplefunctionofgeometry（suchastwo-dimensionalproblemofarbitraryquadrilateralortriangle）ontheunitdomain（piecewisefunction），thedefinitiondoesnotconsiderthewholedomainofthecomplexboundaryconditions，thisisthefiniteelementmethodissuperiortoothersimilarmethodsofoneofthereasonswhy.

Differentphysicalpropertiesandmathematicalmodelsoftheproblem，finiteelementmethodtosolvethebasicstepsarethesame，onlythespecificformulatosolveadifferentderivationandcomputation.FiniteElementAnalysisofthebasicstepsareasfollows:

Thefirststep:

thedefinitionoftheproblemandsolutiondomain:

Inaccordancewiththeactualproblemsolvingdomainapproximationtodeterminethephysicalpropertiesandgeometryoftheregion.

Thesecondstep:

Solvingdomaindiscretization:

Theapproximatesolutionofthedomainwithdifferentsizeandshapeofalimitedandlinkedtoeachotherunit，composedofafin-itenumberofdiscretedomains，thehabitofdivisionasthefiniteelementnetwork.Obvio-uslythesmallertheunit（thefinerthenetwork）issimilartothelevelofdiscretedomain，thebetter，themoreaccurateresults，butthecalculationofthevolumeanderrorwillbelarger，sotosolvethediscretedomainisthefiniteelementmethod，oneofthecoretech-nology.

Thethirdstep:

todeterminethestatevariablesandcontrolmethod:

aspecificphysicalproblemcanusuallybehandledbyagroupofstatevariablesincludetheissueofboundaryconditionsthatthedifferentialequationsforthefiniteelementforsolvingdifferentialequa-tionsareusuallytranslatedintothefunctionalequivalentformsof.

Stepfour:

unitderived:

ontheunittoconstructasuitableapproximatesolution，thatisderivedoutofthefiniteelementtype，includingareasonablechoiceofcoordinatesystemunits，theestablishmentofunittestfunction，toonewayoranotherunitofthestateva-riablesgiventhediscreterelationstoformtheunitmatrix（thestructureofsaidmechani-calstiffnessorflexibilitymatrixarray）.

Inordertoensuretheconvergenceofproblemsolving，therearemanyprinciplesde-rivedunitstofollow.Intermsofengineeringapplications，itisimportanttopayatten-tiontoeachunitofproblem-solvingperformanceandconstraints.Forexample，theunitshouldbebasedontherulesforshape，anddeformednotonlylow-precision，butalsotheriskofmissingrank，willresultinfailuretosolve.

Stepfive:

Solutionassembly:

assemblytoformadiscreteunitofthetotaldomainmatrixequation（Jointequations），reflectingtheapproximatesolutionofthediscretedomaintherequestdomain，thatis，thecontinuityoffunctionmodulestomeettheconditionsforcer-tain.Assemblyunitintheadjacentnode，thestatevariablesandtheirderivatives（ifpossib-le）toestablishcontinuityinthejunctionpoint.

Sixthstep:

solvingsimultaneousequationsandtheresultsoftheinterpretation:

thefiniteelementmethodeventuallyleadtosimultaneousequations.Simultaneousequationscanbeusedtosolvethedirectmethod，theelectionlawandtherandomgenerationmethod.Solv-ingaresult，thestateDepartmentunitnodeapproximationvariables.Theresultsforthequalityanddesignguidelineswillbeprovidedtoallowvaluestoevaluateanddeterminetheneedfordouble-counting.

Inshort，thefiniteelementanalysiscanbedividedintothreestages，pre-treatment，processingandpost-processing.Pre-processingfiniteelementmodelisbuilttocompletetheunitmesh;

post-processingistheacquisitionandprocessingtheresultsoftheanalysis，a-lowsuserstoextractinformationeasytounderstandresults.

Inpractice，thefiniteelementmethodisusuallycomposedofthreemainsteps:

1，pre-processing:

theuserobjecttobeanalyzedtoestablishpartofthemodel，inthismodel，thegeometryofthepartbeingcutintoseveraldiscretesub-region-otherwiseknownas"

modules."

Insomeofthemodulesreferredtoas"

nodes"

ofthediscretepointsconnectedwitheachother.Someofthesenodesarefixeddisplacement，whiletheremainingloadsaregiven.Preparesuchamodelcouldbeextremelytime-consumingprocessiswhythecommercialcompetitionbetweenthelies:

howtousethemostfriendlygraphicalinter-faceofthe"

pre-processingmodule"

，tohelpuserscompletethetediousworkofboring.Somepre-processingmoduleasacomputerizeddrawingandanintegralpartofthede-ignprocess，canbepre-existingCADfilegridcoverage，whichcanbeeasilycompletedbyFiniteElementAnalysis.

2，Analysis:

thepre-processingmoduleprepareddataintofiniteelementprogram,andthusconstitutesasolutionoflinearornonlinearsystemofalgebraicequationsthat

Kij*Uj=Fi

Whereuandf，respectively，foreachnodeofthedisplacementandtheroleofexternalforces.MatrixformofKdependonthetypeofproblemsolving，themodulewilloutlinethetrusswiththelinearelasticstressanalysis.Businessproceduresmaycarryaverylargelibrary，thedifferenttypesofunitsapplicabletoawiderangeofvariousproblems.Finiteelementmethodisoneofthemainadvantagesof:

Manydifferenttypesofproblemsareavailabletodealwiththesameprocedure，thedifferenceisonlyspecifiedfromthecelllibraryfortheproblemindifferentcelltypes.

3，post-processing:

Intheearlyfiniteelementanalysis，usersneedtocarefullystudytheproceduresforcomputingalargenumberoffiguresafter，thatis，themodelsetoutinthediscretepositionofthedisplacementandstress.Thismethodiseasytomissimportanttrendsandhotspots，andthelatestgraphicsprocessingtobeusetohelptheusercom-putingtheresultsofdirectobservation.Typicalpost-processingmodulecandisplaythemodelacrossthecolorlinegraphofstressfordifferentstresslevels，indicatingtheentirestressfieldissimilartotheimagesorPhotoelasticitymoireresults.

附录C.中文翻译

CAE的技术种类有很多，其中包括有限元法,边界元法,有限差法等。

每一种方法各有其应用的领域，