机械毕业设计英文外文翻译5CAE的技术.docx

机械毕业设计英文外文翻译5CAE的技术.docx

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机械毕业设计英文外文翻译5CAE的技术

附录B.英文文献

TherearemanytypesofCAEtechnology,includingthefiniteelementmethod,boundaryelementmethod,finitedifferencemethod.Eachmethodhasitsownapplicationareas,ofwhichtheapplicationoffiniteelementmethodmoreandmoreareas,hasbeenusedinstructuralmechanics,structuraldynamics,thermodynamics,fluidmechanics,circuittheory,electromagnetismandsoon.

   ANSYSsoftwareisthefinancialstructure,fluid,electricfield,magneticfield,acousticfieldanalysisinonelarge-scalefiniteelementanalysissoftware.Bytheworld'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，