外文翻译--拉中拉深壁起皱的分深模设计析 原文.pdf

INTJADVMANUFTECHNOL200219253–2592002SPRINGERVERLAGLONDONLIMITEDANANALYSISOFDRAWWALLWRINKLINGINASTAMPINGDIEDESIGNFKCHENANDYCLIAODEPARTMENTOFMECHANICALENGINEERING,NATIONALTAIWANUNIVERSITY,TAIPEI,TAIWANWRINKLINGTHATOCCURSINTHESTAMPINGOFTAPEREDSQUARECUPSANDSTEPPEDRECTANGULARCUPSISINVESTIGATEDACOMMONCHARACTERISTICOFTHESETWOTYPESOFWRINKLINGISTHATTHEWRINKLESAREFOUNDATTHEDRAWWALLTHATISRELATIVELYUNSUPPORTEDINTHESTAMPINGOFATAPEREDSQUARECUP,THEEFFECTOFPROCESSPARAMETERS,SUCHASTHEDIEGAPANDBLANKHOLDERFORCE,ONTHEOCCURRENCEOFWRINKLINGISEXAMINEDUSINGFINITEELEMENTSIMULATIONSTHESIMULATIONRESULTSSHOWTHATTHELARGERTHEDIEGAP,THEMORESEVEREISTHEWRINKLING,ANDSUCHWRINKLINGCANNOTBESUPPRESSEDBYINCREASINGTHEBLANKHOLDERFORCEINTHEANALYSISOFWRINKLINGTHATOCCURREDINTHESTAMPINGOFASTEPPEDRECTANGULARCUP,ANACTUALPRODUCTIONPARTTHATHASASIMILARTYPEOFGEOMETRYWASEXAMINEDTHEWRINKLESFOUNDATTHEDRAWWALLAREATTRIBUTEDTOTHEUNBALANCEDSTRETCHINGOFTHESHEETMETALBETWEENTHEPUNCHHEADANDTHESTEPEDGEANOPTIMUMDIEDESIGNFORTHEPURPOSEOFELIMINATINGTHEWRINKLESISDETERMINEDUSINGFINITEELEMENTANALYSISTHEGOODAGREEMENTBETWEENTHESIMULATIONRESULTSANDTHOSEOBSERVEDINTHEWRINKLEFREEPRODUCTIONPARTVALIDATESTHEACCURACYOFTHEFINITEELEMENTANALYSIS,ANDDEMONSTRATESTHEADVANTAGEOFUSINGFINITEELEMENTANALYSISFORSTAMPINGDIEDESIGNKEYWORDSDRAWWALLWRINKLE；STAMPINGDIE；STEPPEDRECTANGULARCUP；TAPEREDSQUARECUPS1INTRODUCTIONWRINKLINGISONEOFTHEMAJORDEFECTSTHATOCCURINTHESHEETMETALFORMINGPROCESSFORBOTHFUNCTIONALANDVISUALREASONS,WRINKLESAREUSUALLYNOTACCEPTABLEINAFINISHEDPARTTHEREARETHREETYPESOFWRINKLEWHICHFREQUENTLYOCCURINTHESHEETMETALFORMINGPROCESSFLANGEWRINKLING,WALLWRINKLING,ANDELASTICBUCKLINGOFTHEUNDEFORMEDAREAOWINGTORESIDUALELASTICCOMPRESSIVESTRESSESINTHEFORMINGOPERATIONOFSTAMPINGACOMPLEXSHAPE,DRAWWALLWRINKLINGMEANSTHEOCCURRENCECORRESPONDENCEANDOFFPRINTREQUESTSTOPROFESSORFKCHEN,DEPARTMENTOFMECHANICALENGINEERING,NATIONALTAIWANUNIVERSITY,NO1ROOSEVELTROAD,SEC4,TAIPEI,TAIWAN10617EMAILFKCHENL50560W3MENTUEDUTWOFWRINKLESINTHEDIECAVITYSINCETHESHEETMETALINTHEWALLAREAISRELATIVELYUNSUPPORTEDBYTHETOOL,THEELIMINATIONOFWALLWRINKLESISMOREDIFFICULTTHANTHESUPPRESSIONOFFLANGEWRINKLESITISWELLKNOWNTHATADDITIONALSTRETCHINGOFTHEMATERIALINTHEUNSUPPORTEDWALLAREAMAYPREVENTWRINKLING,ANDTHISCANBEACHIEVEDINPRACTICEBYINCREASINGTHEBLANKHOLDERFORCE；BUTTHEAPPLICATIONOFEXCESSIVETENSILESTRESSESLEADSTOFAILUREBYTEARINGHENCE,THEBLANKHOLDERFORCEMUSTLIEWITHINANARROWRANGE,ABOVETHATNECESSARYTOSUPPRESSWRINKLESONTHEONEHAND,ANDBELOWTHATWHICHPRODUCESFRACTUREONTHEOTHERTHISNARROWRANGEOFBLANKHOLDERFORCEISDIFFICULTTODETERMINEFORWRINKLESOCCURRINGINTHECENTRALAREAOFASTAMPEDPARTWITHACOMPLEXSHAPE,AWORKABLERANGEOFBLANKHOLDERFORCEDOESNOTEVENEXISTINORDERTOEXAMINETHEMECHANICSOFTHEFORMATIONOFWRINKLES,YOSHIDAETAL1DEVELOPEDATESTINWHICHATHINPLATEWASNONUNIFORMLYSTRETCHEDALONGONEOFITSDIAGONALSTHEYALSOPROPOSEDANAPPROXIMATETHEORETICALMODELINWHICHTHEONSETOFWRINKLINGISDUETOELASTICBUCKLINGRESULTINGFROMTHECOMPRESSIVELATERALSTRESSESDEVELOPEDINTHENONUNIFORMSTRESSFIELDYUETAL2,3INVESTIGATEDTHEWRINKLINGPROBLEMBOTHEXPERIMENTALLYANDANALYTICALLYTHEYFOUNDTHATWRINKLINGCOULDOCCURHAVINGTWOCIRCUMFERENTIALWAVESACCORDINGTOTHEIRTHEORETICALANALYSIS,WHEREASTHEEXPERIMENTALRESULTSINDICATEDFOURTOSIXWRINKLESNARAYANASAMYANDSOWERBY4EXAMINEDTHEWRINKLINGOFSHEETMETALWHENDRAWINGITTHROUGHACONICALDIEUSINGFLATBOTTOMEDANDHEMISPHERICALENDEDPUNCHESTHEYALSOATTEMPTEDTORANKTHEPROPERTIESTHATAPPEAREDTOSUPPRESSWRINKLINGTHESEEFFORTSAREFOCUSEDONTHEWRINKLINGPROBLEMSASSOCIATEDWITHTHEFORMINGOPERATIONSOFSIMPLESHAPESONLY,SUCHASACIRCULARCUPINTHEEARLY1990S,THESUCCESSFULAPPLICATIONOFTHE3DDYNAMIC/EXPLICITFINITEELEMENTMETHODTOTHESHEETMETALFORMINGPROCESSMADEITPOSSIBLETOANALYSETHEWRINKLINGPROBLEMINVOLVEDINSTAMPINGCOMPLEXSHAPESINTHEPRESENTSTUDY,THE3DFINITEELEMENTMETHODWASEMPLOYEDTOANALYSETHEEFFECTSOFTHEPROCESSPARAMETERSONTHEMETALFLOWCAUSINGWRINKLESATTHEDRAWWALLINTHESTAMPINGOFATAPEREDSQUARECUP,ANDOFASTEPPEDRECTANGULARPARTATAPEREDSQUARECUP,ASSHOWNINFIG1A,HASANINCLINEDDRAWWALLONEACHSIDEOFTHECUP,SIMILARTOTHATEXISTINGINACONICALCUPDURINGTHESTAMPINGPROCESS,THESHEETMETALONTHEDRAWWALLISRELATIVELYUNSUPPORTED,ANDISTHEREFORE254FKCHENANDYCLIAOFIG1SKETCHESOFAATAPEREDSQUARECUPANDBASTEPPEDRECTANGULARCUPPRONETOWRINKLINGINTHEPRESENTSTUDY,THEEFFECTOFVARIOUSPROCESSPARAMETERSONTHEWRINKLINGWASINVESTIGATEDINTHECASEOFASTEPPEDRECTANGULARPART,ASSHOWNINFIG1B,ANOTHERTYPEOFWRINKLINGISOBSERVEDINORDERTOESTIMATETHEEFFECTIVENESSOFTHEANALYSIS,ANACTUALPRODUCTIONPARTWITHSTEPPEDGEOMETRYWASEXAMINEDINTHEPRESENTSTUDYTHECAUSEOFTHEWRINKLINGWASDETERMINEDUSINGFINITEELEMENTANALYSIS,ANDANOPTIMUMDIEDESIGNWASPROPOSEDTOELIMINATETHEWRINKLESTHEDIEDESIGNOBTAINEDFROMFINITEELEMENTANALYSISWASVALIDATEDBYOBSERVATIONSONANACTUALPRODUCTIONPART2FINITEELEMENTMODELTHETOOLINGGEOMETRY,INCLUDINGTHEPUNCH,DIEANDBLANKHOLDER,WEREDESIGNEDUSINGTHECADPROGRAMPRO/ENGINEERBOTHTHE3NODEAND4NODESHELLELEMENTSWEREADOPTEDTOGENERATETHEMESHSYSTEMSFORTHEABOVETOOLINGUSINGTHESAMECADPROGRAMFORTHEFINITEELEMENTSIMULATION,THETOOLINGISCONSIDEREDTOBERIGID,ANDTHECORRESPONDINGMESHESAREUSEDONLYTODEFINETHETOOLINGGEOMETRYANDFIG2FINITEELEMENTMESHARENOTFORSTRESSANALYSISTHESAMECADPROGRAMUSING4NODESHELLELEMENTSWASEMPLOYEDTOCONSTRUCTTHEMESHSYSTEMFORTHESHEETBLANKFIGURE2SHOWSTHEMESHSYSTEMFORTHECOMPLETESETOFTOOLINGANDTHESHEETBLANKUSEDINTHESTAMPINGOFATAPEREDSQUARECUPOWINGTOTHESYMMETRICCONDITIONS,ONLYAQUARTEROFTHESQUARECUPISANALYSEDINTHESIMULATION,THESHEETBLANKISPUTONTHEBLANKHOLDERANDTHEDIEISMOVEDDOWNTOCLAMPTHESHEETBLANKAGAINSTTHEBLANKHOLDERTHEPUNCHISTHENMOVEDUPTODRAWTHESHEETMETALINTOTHEDIECAVITYINORDERTOPERFORMANACCURATEFINITEELEMENTANALYSIS,THEACTUALSTRESS–STRAINRELATIONSHIPOFTHESHEETMETALISREQUIREDASPARTOFTHEINPUTDATAINTHEPRESENTSTUDY,SHEETMETALWITHDEEPDRAWINGQUALITYISUSEDINTHESIMULATIONSATENSILETESTHASBEENCONDUCTEDFORTHESPECIMENSCUTALONGPLANESCOINCIDINGWITHTHEROLLINGDIRECTION0ANDATANGLESOF45AND90TOTHEROLLINGDIRECTIONTHEAVERAGEFLOWSTRESSH9268,CALCULATEDFROMTHEEQUATIONH9268H11005H92680H110012H926845H11001H926890/4,FOREACHMEASUREDTRUESTRAIN,ASSHOWNINFIG3,ISUSEDFORTHESIMULATIONSFORTHESTAMPINGSOFTHETAPEREDSQUARECUPANDALSOFORTHESTEPPEDRECTANGULARCUPALLTHESIMULATIONSPERFORMEDINTHEPRESENTSTUDYWERERUNONANSGIINDIGO2WORKSTATIONUSINGTHEFINITEELEMENTPROGRAMPAMFSTAMPTOCOMPLETETHESETOFINPUTDATAREQUIREDFIG3THESTRESS–STRAINRELATIONSHIPFORTHESHEETMETALDRAWWALLWRINKLINGINASTAMPINGDIEDESIGN255FORTHESIMULATIONS,THEPUNCHSPEEDISSETTO10MSH110021ANDACOEFFICIENTOFCOULOMBFRICTIONEQUALTO01ISASSUMED3WRINKLINGINATAPEREDSQUARECUPASKETCHINDICATINGSOMERELEVANTDIMENSIONSOFTHETAPEREDSQUARECUPISSHOWNINFIG1AASSEENINFIG1A,THELENGTHOFEACHSIDEOFTHESQUAREPUNCHHEAD2WP,THEDIECAVITYOPENING2WD,ANDTHEDRAWINGHEIGHTHARECONSIDEREDASTHECRUCIALDIMENSIONSTHATAFFECTTHEWRINKLINGHALFOFTHEDIFFERENCEBETWEENTHEDIMENSIONSOFTHEDIECAVITYOPENINGANDTHEPUNCHHEADISTERMEDTHEDIEGAPGINTHEPRESENTSTUDY,IEGH11005WDH11002WPTHEEXTENTOFTHERELATIVELYUNSUPPORTEDSHEETMETALATTHEDRAWWALLISPRESUMABLYDUETOTHEDIEGAP,ANDTHEWRINKLESARESUPPOSEDTOBESUPPRESSEDBYINCREASINGTHEBLANKHOLDERFORCETHEEFFECTSOFBOTHTHEDIEGAPANDTHEBLANKHOLDERFORCEINRELATIONTOTHEOCCURRENCEOFWRINKLINGINTHESTAMPINGOFATAPEREDSQUARECUPAREINVESTIGATEDINTHEFOLLOWINGSECTIONS31EFFECTOFDIEGAPINORDERTOEXAMINETHEEFFECTOFDIEGAPONTHEWRINKLING,THESTAMPINGOFATAPEREDSQUARECUPWITHTHREEDIFFERENTDIEGAPSOF20MM,30MM,AND50MMWASSIMULATEDINEACHSIMULATION,THEDIECAVITYOPENINGISFIXEDAT200MM,ANDTHECUPISDRAWNTOTHESAMEHEIGHTOF100MMTHESHEETMETALUSEDINALLTHREESIMULATIONSISA380MMH11003380MMSQUARESHEETWITHTHICKNESSOF07MM,THESTRESS–STRAINCURVEFORTHEMATERIALISSHOWNINFIG3THESIMULATIONRESULTSSHOWTHATWRINKLINGOCCURREDINALLTHREETAPEREDSQUARECUPS,ANDTHESIMULATEDSHAPEOFTHEDRAWNCUPFORADIEGAPOF50MMISSHOWNINFIG4ITISSEENINFIG4THATTHEWRINKLINGISDISTRIBUTEDONTHEDRAWWALLANDISPARTICULARLYOBVIOUSATTHECORNERBETWEENADJACENTWALLSITISSUGGESTEDTHATTHEWRINKLINGISDUETOTHELARGEUNSUPPORTEDAREAATTHEDRAWWALLDURINGTHESTAMPINGPROCESS,ALSO,THESIDELENGTHOFTHEPUNCHHEADANDTHEDIECAVITYFIG4WRINKLINGINATAPEREDSQUARECUPGH1100550MMOPENINGAREDIFFERENTOWINGTOTHEDIEGAPTHESHEETMETALSTRETCHEDBETWEENTHEPUNCHHEADANDTHEDIECAVITYSHOULDERBECOMESUNSTABLEOWINGTOTHEPRESENCEOFCOMPRESSIVETRANSVERSESTRESSESTHEUNCONSTRAINEDSTRETCHINGOFTHESHEETMETALUNDERCOMPRESSIONSEEMSTOBETHEMAINCAUSEFORTHEWRINKLINGATTHEDRAWWALLINORDERTOCOMPARETHERESULTSFORTHETHREEDIFFERENTDIEGAPS,THERATIOH9252OFTHETWOPRINCIPALSTRAINSISINTRODUCED,H9252BEINGH9280MIN/H9280MAX,WHEREH9280MAXANDH9280MINARETHEMAJORANDTHEMINORPRINCIPALSTRAINS,RESPECTIVELYHOSFORDANDCADDELL5HAVESHOWNTHATIFTHEABSOLUTEVALUEOFH9252ISGREATERTHANACRITICALVALUE,WRINKLINGISSUPPOSEDTOOCCUR,ANDTHELARGERTHEABSOLUTEVALUEOFH9252,THEGREATERISTHEPOSSIBILITYOFWRINKLINGTHEH9252VALUESALONGTHECROSSSECTIONM–NATTHESAMEDRAWINGHEIGHTFORTHETHREESIMULATEDSHAPESWITHDIFFERENTDIEGAPS,ASMARKEDINFIG4,AREPLOTTEDINFIG5ITISNOTEDFROMFIG5THATSEVEREWRINKLESARELOCATEDCLOSETOTHECORNERANDFEWERWRINKLESOCCURINTHEMIDDLEOFTHEDRAWWALLFORALLTHREEDIFFERENTDIEGAPSITISALSONOTEDTHATTHEBIGGERTHEDIEGAP,THELARGERISTHEABSOLUTEVALUEOFH9252CONSEQUENTLY,INCREASINGTHEDIEGAPWILLINCREASETHEPOSSIBILITYOFWRINKLINGOCCURRINGATTHEDRAWWALLOFTHETAPEREDSQUARECUP32EFFECTOFTHEBLANKHOLDERFORCEITISWELLKNOWNTHATINCREASINGTHEBLANKHOLDERFORCECANHELPTOELIMINATEWRINKLINGINTHESTAMPINGPROCESSINORDERTOSTUDYTHEEFFECTIVENESSOFINCREASEDBLANKHOLDERFORCE,THESTAMPINGOFATAPEREDSQUARECUPWITHDIEGAPOF50MM,WHICHISASSOCIATEDWITHSEVEREWRINKLINGASSTATEDABOVE,WASSIMULATEDWITHDIFFERENTVALUESOFBLANKHOLDERFORCETHEBLANKHOLDERFORCEWASINCREASEDFROM100KNTO600KN,WHICHYIELDEDABLANKHOLDERPRESSUREOF033MPAAND198MPA,RESPECTIVELYTHEREMAININGSIMULATIONCONDITIONSAREMAINTAINEDTHESAMEASTHOSESPECIFIEDINTHEPREVIOUSSECTIONANINTERMEDIATEBLANKHOLDERFORCEOF300KNWASALSOUSEDINTHESIMULATIONTHESIMULATIONRESULTSSHOWTHATANINCREASEINTHEBLANKHOLDERFORCEDOESNOTHELPTOELIMINATETHEWRINKLINGTHATOCCURSATTHEDRAWWALLTHEH9252VALUESALONGTHECROSSSECTIONFIG5H9252VALUEALONGTHECROSSSECTIONM–NFORDIFFERENTDIEGAPS256FKCHENANDYCLIAOM–N,ASMARKEDINFIG4,ARECOMPAREDWITHONEANOTHERFORTHESTAMPINGPROCESSESWITHBLANKHOLDERFORCEOF100KNAND600KNTHESIMULATIONRESULTSINDICATETHATTHEH9252VALUESALONGTHECROSSSECTIONM–NAREALMOSTIDENTICALINBOTHCASESINOR