完整版毕业设计外文翻译9570963Word格式.docx
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Chuantao(C.T.)Wang
GeneralMotorsCorp.ManufacturingEngineering,DieCenter,2000Centerpoint,Pontiac,MI48341
Abstract.Inthepastdecade,sheetmetalforminganddiedevelopmenttransformedtoascience-basedandtechnology-drivenengineeringandmanufacturingenterprisefromatryout-basedcraft.StampingCAE,especiallythesheetmetalformingsimulation,asoneofthecorecomponentsindigitaldiemakinganddigitalstamping,this.Thestampingsimulationtechnologyanditsindustrialapplications,diedevelopments,dieconstructionandtryout,andproductionstamping.ThestampingCAEcommunityofthestampingCAEtechnologyandbusinessdemandsopensevengreateropportunitiesandchallengestostampingCAEcommunityintheareasof:
(1)continuouslyimprovingsimulationaccuracy,drasticallyreducingsimulationtime-in-system,andimprovingoperationalability(friendliness),
(2)resolvingthoseandskidimpactlines),(3)resolvingtotalmanufacturabilityproblemsinlinedieoperationsincludingblanking,drawredraw,trimpiercing,andflanging,and(4)overcomingnewproblemsinformingnewsheetmaterialswithnewformingtechniques.Inthisarticle,theauthorfirstprovidesanoverviewofthestampingCAEtechnologyadventuresandachievements,andindustrialapplicationsinthepastdecade.Thentheauthorpresentsasummaryofincreasingmanufacturabilityneedsfromtheformabilitytototalqualityandtotalmanufacturabilityofsheetmetalstampings.Finally,thepaperoutlinesthenewneedsandtrendsforcontinuousimprovementsandinnovationstomeetincreasingchallengesinlinedieformabilityandqualityrequirementsinautomotivestamping.
INTRODUCTION
Theformingsimulation-basedstampingCAEtechnologyanditsindustrialapplications,diedevelopments,dieconstructionandtryout,andproductionstampinginthepastdecade[1].SincetheNumiSheetConferencestartedin1991,stampingCAEcommunityfundamentalunderstandingofsheetmetalformability,formingmechanics,numericalmethods,butalsothemostsignificantly,thefruitfulindustrialapplicationsinawiderangeofbusinesssegments.
TheautomotivedieandstampingindustrybenefitmostfromthestampingCAE.Thetechnologyadvancementspeedsupainautomotivediedevelopmentandstampingfromatryout-basedcrafttoascience-basedandtechnologydrivenengineeringandmanufacturingenterprise.StampingCAE,especiallythesheetmetalformingsimulation,thistransition[1].InGeneralMotors,thestampingCAEtechnologyextensivelyusedinmanywaystosignificantlyimpactonvariousbusinesssegmentsofvehicleandtoolingdevelopmentprocesses.Theapplicationsandbenefitsaresummarizedasfollowing:
•StampingCAEisusedasaDFMtool(DesignforManufacturability)toassessandvalidatetheproductstylingsurfacedesignstoensuresamanufacturablesheetproductdesignforagoodstartofvehicleprogram.
•Itisusedasadieengineeringtoolinstampinglinediedevelopmentstovalidateandreshapebinderandaddendumoneverynewlineofdies(blanking,draw,trim,flanging,andspringbackresolutions).
•Itisusedasatryouttooltoreplacesofttoolsandassociatedtryoutsandtoshorten)dietryouttosignificantlyreducediecostandlead-time.
•Itisusedasaproductiontooltoprovideproductionstampingconditions(beadspecifications,lube,bindertonnage,pressload,blankgaging,diesurfacerelief,gripperlocationsforautomation,etc.).
•Itisusedasaproblemsolvingtoolforproductiontroubleshootingtoreproducemanufacturingproblems,toidentifytherootcausesandtoprovidesolutionsforprocesscontrolimprovements.
•Itisusedasasimulation-basedmanufacturingguidetousetheCAEoutputtodriveconsistencyamongdieengineering,dieconstruction,andproductionstamping.
•Finally,thestampingCAEisusedasalearningtooltoexploreandgainnewknowledgeandapplicationguidancefornewformingtechniques(tubesheetapplicationsjustafewshortyears.
AsmorestampingCAEapplicationdomainsareexplored,themoretechnicallimitationsandinadequaciesarediscovered.Inturn,therecomeapplication-driventechnologydevelopmentandadvancement.Inthispaper,theauthorreviewstheevolutionsofstampingCAEtechnologyanditsindustrialapplicationsinautomotiveproductdesign,diedevelopmentandproductionstamping.Theindustrialneedsfortechnologyimprovementsaredescribed.Thelimitationsofcurrenttechnologyareidentifiedandtheneedsfortechnologydevelopmentsarereviewed.
EVOLUTIONSOFSTAMPINGCAE
StampingCAEtechnologydevelopmentandindustrialapplicationsevolvinginthreemainstages,namely,thefundamentalresearchandlabworkin1970s-1980s,pioneerindustrialtrialsinearlier1990s,andthemassproductionapplicationsaftermid1990sto2000s.
RESEARCHANDDEVELOPMENT(1970S-1980S)
From1970sto1980s,themajordevelopmentswerethefundamentalstudiesofsheetformingmechanics,numericalmodeling,andcomputationalmethods.Theresearchworkwasprimarilyaccomplishedinacademiaandresearchinstitutions.Reference[3]providesacomprehensivereviewoftheresearchworkduringthatperiod.Theresearchtopicswereconcentratedonnumericalformulationssuchasmembranevs.shell,staticimplicitvs.Dynamicexplicit),toolsheetcontact,materialmodeling(yieldfunctions,workearly1990s,thesheetformingindustry,especiallytheautomotivestamping,attemptedthenumericalsimulationsforlargeandcomplicatedbodypanels.TheBig3sinDetroitledtheworldinthisendeavorbydevelopingtheirproprietarysimulation
toolsforlarge3-dimensionalproblems.Stoughton[8]ofGeneralMotorsdevelopedPanelFormcombiningautomaticmeshgenerationwithmembraneformulationbasedonearlierworkofWangdidwhensametime,Wangledthe
ChryslergroupdevelopedC-FormandTanginFordMotordevelopedMetalForm,andbothcodeswerebasedonshellformulationwithstaticandimplicitsolvers.Othergroupsincludingthecommercialsoftwarevendorsalsodevelopedtheindustrial
orientedsoftware,noticeably,PamstampfromESI(EngineeringSystemsInternational)ofFrance,LSDyna3dfromLSTC(LivermoreSoftwareTechnologyCo.),bothcodesarebasedonshellformulationanddynamicexplicitsolver,andbothPamstampandLSDyna3D–Dyna3D,apublicdomaincodefromLivermoreLaboratory,aUSAgovernmentfundedresearchinstitution.Theprofessionalconferencesinnumericalsimulationsofmetalformingprocessinearlier1990s,especiallytheNumiSheet[13-17]andNumiForm[18-25]greatlyimprovedourunderstandingofallimportantaspectsoffiniteelementsimulationsofsheetmetalforming.TheNumiSheetConferencesprovidedcomprehensiveexamsforthereadinessofthesimulationtechnologyforindustrialproblems.Themajordifficultiesandchallengesdiscoveredforindustrializationduringthatperiodwere
(1)finiteelementmodeling(robustness(time(tools(suchasPamstampandLS-Dyna3D)withfullshellformulationsanddynamicimplicitsolvers.Thefiniteelementcodeswithone-stepmembraneformulationwerealsogotattentionoftheindustrialusersforthecapabilitiesofusingthelargenumberoffinerelementsandshortcomputationtimealthoughtheaccuracyoftheresultswasquestionable.
TheeconomicdownturnsinUSAinearly1990sandtherecoveryeffortsbytheautomotiveindustry,especiallyGeneralMotorsNorthAmericanOperations,pushedtheapplicationsofmath-basedtoolsandprocessindesign,engineeringandmanufacturing.Bythemidof1990s,thestampingCAEemergedasnewengineeringfieldindieandsheetmetalformingindustry.Anewprofession–stampingCAEengineer,createdsincethen.TheNumiSheet1996DearbornMichiganmarkedthebeginningofmassproductionapplicationsofstampingsimulationsworldwide[15].In1996,afterthreeyearintenseintegratedtechnologydevelopmentandproductionization,GMNorthAmericanStampingcompleteditsinapplyingsimulationbaseddigitalvalidationsforalldrawdiesengineeredandconstructedin—1990s,theindustrialapplicationsofstampingCAEtechnologyweremainlyfocusedonformingsimulationsfordrawdiethatistheoneofthelinediesneededtoformanautomotivepanel.ThestampingCAEcommunitymainlyfocusedonpredictingthetraditionalformabilityproblems(splitsandexcessivethinning,wrinkles).GMpredictingformabilityproblemswithverydrawdieforming.Fig.1illustratesexcellentcorrelationsbetweenpredictionsandmeasurementsforanaluminumdecklid.Thethinningwasmeasuredverypreciselyusingthepinpointmicronmeteratthesamelocationsidentifiedinsimulations,andthesurfacestrainsweremeasuredbyconventionalcirclegridsthatnormallybands.Thethinningcorrelationisexcellent,andthepredictedmajorandminorstrainsarewithinthemeasurementbands.
FIGURE1.Thinningandstrainsmeasurements
Thinning
FIGURE2.Thinningcomparison
MajorStrain
FIGURE3.Majorstraincomparison
MinorStrain
FIGURE4.Minorstraincomparison
MASSPRODUCTIONAPPLICATIONSANDCHALLENGES(2000s)
Intoday’sdieandstampingindustry,thestampingCAEfordigitalvalidationsofdiedevelopmentsbeforeproductiontrialsisacriticalbusinessforlead-timereduction,costreductionandqualityimprovements.TheindustryandCAEengineerspushthetechnologyenveloplimitandattempttoapplythesimulationstoalmostallpossibleareasofsheetmetalformingtomaximizethepowerofsimulationanditsfinancialbenefits.Intheautomotivestampingaresummarizedasfollowing.
Increasingpartsizeandshapecomplexitysuchaswholebodysidepanels,andmultipleattac