文献翻译原文在冲压过程模拟产品和工艺设计最新应用Word下载.docx
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(1)tooptimizetheproductdesignbyanalyzingformabilityattheproductdesignstageand
(2)toreducethetryouttimeandcostinprocessdesignbypredictingthedeformationprocessinadvanceduringthediedesignstage.Foreachoftheseobjectives,twokindsofFE-simulationsareapplied.Pam-Stamp,anincrementaldynamic-explicitFEMcodereleasedbyEngineeringSystemsInt'
l,matchesthesecondobjectivewellbecauseitcandealwithmostofthepracticalstampingparameters.FAST_FORM3D,aone-stepFEMcodereleasedbyFormingTechnologies,matchesthefirstobjectivebecauseitonlyrequiresthepartgeometryandnotthecomplexprocessinformation.
Inapreviousstudy,thesetwoFEcodeswereappliedtocomplex-shapedpartsusedinmanufacturingautomobilesandconstructionmachinery.Theircapabilitiesinpredictingformabilityissuesinstampingwereevaluated.ThispaperreviewstheresultsofthisstudyandsummarizestherecommendedproceduresforobtainingaccurateandreliableresultsfromFEsimulations.
Inanotherstudy,theeffectofcontrollingtheblankholderforce(BHF)duringthedeepdrawingofhemispherical,dome-bottomedcupswasinvestigated.Thestandardautomotivealuminum-killed,drawing-quality(AKDQ)steelwasusedaswellashighperformancematerialssuchashighstrengthsteel,bakehardsteel,andaluminum6111.ItwasdeterminedthatvaryingtheBHFasafunctionofstrokeimprovedthestraindistributionsinthedomedcups.
Keywords:
Stamping;
Process;
stimulation;
Processdesign
1.Introduction
Thedesignprocessofcomplexshapedsheetmetalstampingssuchasautomotivepanels,consistsofmanystagesofdecisionmakingandisaveryexpensiveandtimeconsumingprocess.Currentlyinindustry,manyengineeringdecisionsaremadebasedontheknowledgeofexperiencedpersonnelandthesedecisionsaretypicallyvalidatedduringthesofttoolingandprototypingstageandduringharddietryouts.Veryoftenthesoftandhardtoolsmustbereworkedorevenredesignedandremanufacturedtoprovidepartswithacceptablelevelsofquality.
ThebestcasescenariowouldconsistoftheprocessoutlinedinFig.1.Inthisdesignprocess,theexperiencedproductdesignerwouldhaveimmediatefeedbackusingaspeciallydesignsoftwarecalledone-stepFEMtoestimatetheformabilityoftheirdesign.Thiswouldallowtheproductdesignertomakenecessarychangesupfrontasopposedtodownthelineafterexpensivetoolinghasbeenmanufactured.One-stepFEMisparticularlysuitedforproductanalysissinceitdoesnotrequirebinder,addendum,orevenmostprocessconditions.Typicallythisinformationisnotavailableduringtheproductdesignphase.One-stepFEMisalsoeasytouseandcomputationallyfast,whichallowsthedesignertoplay“whatif”withoutmuchtimeinvestment.
Fig.1.Proposeddesignprocessforsheetmetalstampings.
Oncetheproducthasbeendesignedandvalidated,thedevelopmentprojectwouldenterthe“timezero”phaseandbepassedontothediedesigner.Thediedesignerwouldvalidatehis/herdesignwithanincrementalFEMcodeandmakenecessarydesignchangesandperhapsevenoptimizetheprocessparameterstoensurenotjustminimumacceptabilityofpartquality,butmaximumachievablequality.Thisincreasesproductqualitybutalsoincreaseprocessrobustness.IncrementalFEMisparticularlysuitedfordiedesignanalysissinceitdoesrequirebinder,addendum,andprocessconditionswhichareeitherknownduringdiedesignordesiredtobeknown.
Thevalidateddiedesignwouldthenbemanufactureddirectlyintothehardproductiontoolingandbevalidatedwithphysicaltryoutsduringwhichtheprototypepartswouldbemade.Tryouttimeshouldbedecreasedduetotheearliernumericalvalidations.Redesignandremanufacturingofthetoolingduetounforeseenformingproblemsshouldbeathingofthepast.Thedecreaseintryouttimeandeliminationofredesign/remanufacturingshouldmorethanmakeupforthetimeusedtonumericallyvalidatethepart,die,andprocess.
Optimizationofthestampingprocessisalsoofgreatimportancetoproducersofsheetstampings.Bymodestlyincreasingone'
sinvestmentinpresses,equipment,andtoolingusedinsheetforming,onemayincreaseone'
scontroloverthestampingprocesstremendously.Ithasbeenwelldocumentedthatblankholderforceisoneofthemostsensitiveprocessparametersinsheetformingandthereforecanbeusedtopreciselycontrolthedeformationprocess.
BycontrollingtheblankholderforceasafunctionofpressstrokeANDpositionaroundthebinderperiphery,onecanimprovethestraindistributionofthepanelprovidingincreasedpanelstrengthandstiffness,reducedspringbackandresidualstresses,increasedproductqualityandprocessrobustness.Aninexpensive,butindustrialqualitysystemiscurrentlybeingdevelopedattheERC/NSMusingacombinationofhydraulicsandnitrogenandisshowninFig.2.UsingBHFcontrolcanalsoallowengineerstodesignmoreaggressivepanelstotakeadvantagetheincreasedformabilitywindowprovidedbyBHFcontrol.
Fig.2.BlankholderforcecontrolsystemandtoolingbeingdevelopedattheERC/NSMlabs.
Threeseparatestudieswereundertakentostudythevariousstagesofthedesignprocess.Thenextsectiondescribesastudyoftheproductdesignphaseinwhichtheone-stepFEMcodeFAST_FORM3D(FormingTechnologies)wasvalidatedwithalaboratoryandindustrialpartandusedtopredictoptimalblankshapes.Section4summarizesastudyofthediedesignstageinwhichanactualindustrialpanelwasusedtovalidatetheincrementalFEMcodePam-Stamp(EngineeringSystemsInt'
l).Section5coversalaboratorystudyoftheeffectofblankholderforcecontrolonthestraindistributionsindeepdrawn,hemispherical,dome-bottomedcups.
2.Productsimulation–applications
TheobjectiveofthisinvestigationwastovalidateFAST_FORM3D,todetermineFAST_FORM3D'
sblankshapepredictioncapability,andtodeterminehowone-stepFEMcanbeimplementedintotheproductdesignprocess.FormingTechnologieshasprovidedtheirone-stepFEMcodeFAST_FORM3DandtrainingtotheERC/NSMforthepurposeofbenchmarkingandresearch.FAST_FORM3Ddoesnotsimulatethedeformationhistory.Insteaditprojectsthefinalpartgeometryontoaflatplaneordevelopablesurfaceandrepositionsthenodesandelementsuntilaminimumenergystateisreached.ThisprocessiscomputationallyfasterthanincrementalsimulationslikePam-Stamp,butalsomakesmoreassumptions.FAST_FORM3Dcanevaluateformabilityandestimateoptimalblankgeometriesandisastrongtoolforproductdesignersduetoitsspeedandeaseofuseparticularlyduringthestagewhenthediegeometryisnotavailable.
InordertovalidateFAST_FORM3D,wecompareditsblankshapepredictionwithanalyticalblankshapepredictionmethods.Thepartgeometryusedwasa5
in.deep12
in.by15
in.rectangularpanwitha1
in.flangeasshowninFig.3.Table1liststheprocessconditionsused.Romanovski'
sempiricalblankshapemethodandthesliplinefieldmethodwasusedtopredictblankshapesforthispartwhichareshowninFig.4.
Fig.3.RectangularpangeometryusedforFAST_FORM3Dvalidation.
Table1.ProcessparametersusedforFAST_FORM3Drectangularpanvalidation
Fig.4.Blankshapedesignforrectangularpansusinghandcalculations.
(a)Romanovski'
sempiricalmethod;
(b)sliplinefieldanalyticalmethod.
Fig.5(a)showsthepredictedblankgeometriesfromtheRomanovskimethod,sliplinefieldmethod,andFAST_FORM3D.Theblankshapesagreeinthecornerarea,butdiffergreatlyinthesideregions.Fig.5(b)–(c)showthedraw-inpatternafterthedrawing
process
oftherectangularpanassimulatedbyPam-Stampforeachofthepredictedblankshapes.Thedraw-inpatternsforallthreerectangularpansmatchedinthecornersregionsquitewell.Thesliplinefieldmethod,though,didnotachievetheobjective1
in.flangeinthesideregion,whiletheRomanovskiandFAST_FORM3Dmethodsachievedthe1
in.flangeinthesideregionsrelativelywell.Further,onlytheFAST_FORM3Dblankagreesinthecorner/sidetransitionregions.Moreover,theFAST_FORM3DblankhasabetterstraindistributionandlowerpeakstrainthanRomanovskiascanbeseeninFig.6.
Fig.5.VariousblankshapepredictionsandPam-Stampsimulationresultsfortherectangularpan.
(a)Threepredictedblankshapes;
(b)deformedsliplinefieldblank;
(c)deformedRomanovskiblank;
(d)deformedFAST_FORM3Dblank.
Fig.6.ComparisonofstraindistributionofvariousblankshapesusingPam-Stampfortherectangularpan.
(a)DeformedRomanovskiblank;
(b)deformedFAST_FORM3Dblank.
Tocontinuethisvalidationstudy,anindustrialpartfromtheKomatsuLtd.waschosenandisshowninFig.7(a).WepredictedanoptimalblankgeometrywithFAST_FORM3DandcompareditwiththeexperimentallydevelopedblankshapeasshowninFig.7(b).Asseen,theblanksaresimilarbuthavesomedifferences.
Fig.7.FAST_FORM3Dsimulationresultsforinstrumentcovervalidation.
(a)FAST_FORM3D'
sfo