外文翻譯熱擠壓模的壓力分析和優(yōu)化設計.pdf

TSINGHUASCIENCEANDTECHNOLOGYISSN1007-021410/24pp290-293Volume9,Number3,June2004StressAnalysisandOptimumDesignofHotExtrusionDies*SHUAICijun(帥詞俊)*,XIAOGang(肖剛),NIZhengshun(倪正順)CollegeofMechanicalandElectronicEngineering,CentralSouthUniversity,Changsha410083,ChinaAbstract:Athree-dimensionalmodelofahotextrusiondiewasdevelopedbyusingANSYSsoftwareanditsseconddevelopmentlanguageANSYSparametricdesignlanguage.Afiniteelementanalysisandop-timumdesignwerecarriedout.Thethree-dimensionalstressdiagramshowsthatthestressconcentrationisrathersevereinthebridgeofthehotextrusiondie,andthatthestressdistributionisveryuneven.Theopti-mumdimensionsareobtained.Theresultsshowthattheoptimumheightoftheextrusiondieis89.596mm.Theoptimumradiiofdiffluenceholesare65.048mmand80.065mm.Thestressconcentrationisreducedby27%.Keywords:three-dimensionalmethod；modeling；hotextrusiondie；optimumdesignIntroductionWiththestandardoflivingcontinuouslyimproving,aluminiumpartsarewidelyusedineverywalkoflife.Productsarebecomingmoreandmorediverseandcomplicatedandprecisionsarehigherandhigher1,2.Theextrusiondieisthebasisoftheextrusionprocess.Itnotonlydeterminesproductshape,size,precision,andsurfacestate,butalsoaffectsproductperformance.Sotheextrusiondieisthekeytoextrusiontechnology.Studiestoimproveextrusiondiequalityandprolongitslifespanusuallyattempttosimplify3-Dfiniteele-mentmodelto2-D,butitisonlyrightforsimplestruc-turalshapes.Withouta3-Dfiniteelementanalysis,theresultscannotgivepracticalmanufacturinghelpandofferusefulinformation3-5.Inthispaper,aluminiumprofileextrusiondiewasmodeledtogetinoptimumdesign6-8.1SolidModelingFigure1showsthemaledieofahotextrusionplanarcombineddie.Itsexternaldiameteris227.000mm,itsheightis80.000mm.OtherparametersareshowninFig.1.Themodelingmethodisasfollows.1.1CoordinatesofP1andP5ThecoordinatesofthepointofintersectionbetweenthebeelineL(y=kx+b)andthecirculararc(x2+y2=R2)are22221,52()(1)()1kbkbkbRxk+=+(1)1,51,5ykxb=+(2)1.2CoordinatesofP2andP6Thecoordinatesoftheintersectionpoint(P2)betweenbeelineL1(y=kx+b)andbeelineL2(y=S1)areReceived:2003-12-10；selectedfromProceedingsoftheSymposiumonFrontiersandChallengesofMechanicalScienceandTechnologySupportedbytheFundfortheDoctoralProgramofHigherEducationofChina(No.20010533010)Towhomcorrespondenceshouldbeaddressed.E-mail:；Tel:86-731-883685812Sbxk=(3)y2=S1(4)Thecoordinatesoftheintersectionpoint(P6)betweenSHUAICijun(帥詞俊)etal：StressAnalysisandOptimumDesignofHotExtrusionDies291Fig.1SketchmapofthehotextrusiondiebeelineL3(y=kx+b)andbeelineL4(y=S1)arex6=S2(5)y6=kx2+b(6)1.3CoordinatesofP3,P4,P7,andP8P3andP1aresymmetricaboutthey-axis.P4andP2arealsosymmetricaboutthey-axis.P7andP5aresym-metricaboutthex-axis.P8andP6arealsosymmetricaboutthex-axis.1.4VariablesintheequationsInEqs.(1)-(6),forpointsP1andP2,b=2121kTk+andR=R1.ForpointsP5andP6,b=2221kTk+andR=R2.R1,R2,T1,T2,S1,andS2arethechangerulealongtheheight(H)ofthedieexpressedasthefunctionsR1=f1(z),R2=f2(z),T1=f3(z),T2=f4(z),S1=f5(z),andS2=f6(z),z0,H.1.5SectionshapeatsomeheightWithlineslinkingP1-P4,P5-P8,withcirculararcfillet-ingatthepointofintersection(P1-P8),thesectionshapeatsomeheightisobtained.1.6SectionshapeateveryheightHisdividedtointerfacialnumber(INUM)equalparts(INUMisdecidedbytheprecision,iftheINUMishigher,theprecisionisbetter).ThesectionshapeisdrawnateveryheightasshowninFig.2.Fig.2Dielinediagram1.7SmoothcurvedsurfaceUsingSKINcommandinANSYS,smoothcurvedsur-faceswerebuiltalongthelines.Theyarethesurfacesoftheinfluencehole.UsingtheVA(itgeneratesavol-umeboundedbyexistingarea)command,asolidwascreatedfromthosesurfaces.1.8SymmetryofthedieThemainbodyandkernelofthedieweredrawnusingtheBooleanoperationsofadd,subtract,etc.(Fig.3).Thesymmetryofthediewasusedtoacceleratethecomputationsusinga1/4-solidmodelforthefiniteelementanalysis(Fig.4).2ComputingModelAplanardiethatextrudesthealuminiumalloy(6063Al-Mg-Si)wasusedasanexample.TheliquidoidofAlis6579,andthemelttemperatureofAl+Mg2Siis558.Takingtheextrusionpressureandtheprod-uctsqualityintoaccount,theworkingtemperaturewas292TsinghuaScienceandTechnology,June2004,9(3):290293)determinedtobe450.Thediematerialis4Cr5MoSiV1(H13).Belowthe450,itsYoungmodulusandPossionratioare210GPaand0.25,respectively.Itsyieldstrengthis1200MPa.Thefrictioncoefficientis0.3.TheSolid923-Dsolidelementwasusedtocarrythroughthefreemesh.Inordertoloadthefrictionalforcewhileextruding,thesurfaceeffectelementSurf154wasusedtoproducetheregularquadrangles(Fig.5).Forthe1600textruder,theextrusionintensitywascomputedusingEq.(7)10.ThevaluesareshowninTable1.12zztdzzd()(PPPRTTTRTT=+=+(7)Fig.5FrictionalforceloadedTable1IntensityofeachpartinthedieFig.3DiesolidmodelFig.4Onequarterofthesolidmodel(MPa)RzTzTtTdzRzTdTP83.4227.41222.7219.53191.8053.2314.38612.54Thebridgecollapseoftentakesplaceinthedie.Anditsstrengthisdeterminedbytheheightandthedistri-butionofthediffluenceholes.Inthispaper,theheight(H)andtheradii(R1andR2)ofthediffluenceholeswereusedasdesignvariablesandthemaximumequivalentpressure(max)wasusedasthegoalfunc-tion.ThedesignvariablerangesarelistedinTable2.Table2DesignvariablerangeR1/mmR2/mmH/mm1/()2/()65.000-85.00080.000-98.00060.000-90.00020.000-40.00020.000-40.0003ComputedResultsFigure6istheequivalentstressdiagram.FromFig.6wecanseethatthestressislargestatthebridge,asex-pected24maximumequivalentstressvaluesarelistedinTable3fromlargetosmall.Thedatashowsthatthenodalmaximumequivalentstressis1066.5MPa,whichis14.5%higherthanthesecondone(912.0MPa),andthatthestressconvergenceisverysevereinthebridge,thispartisapttoproducecrack.Fig.6MaximumequivalentstressTable3NodesstressvaluesNodecode97152871969839507141156702727710723700r/MPa1066.5912.0832.7811.6804.4795.3789.9778.8775.8769.0763.6763.5Nodecode7397087067317591778704747690743694696r/MPa759.3756.8755.9739.8739.1736.0734.3715.9706.4700.3700.1695.6SHUAICijun(帥詞俊)etal：StressAnalysisandOptimumDesignofHotExtrusionDies293TheinitialvalueofthedesignvariablesR1,R2,H,1,and2were75.000mm,88.000mm,80.000mm,30.000,and30.000,respectively,andthemaximumequivalentstressmax=1066.5MPa.Inthe21itera-tions,theoptimumiterationwastheeighteenth.ThedesignvariablevalueswereR1=65.048mm,R2=80.065mm,H=89.596mm,1=30.642,2=20.045.Themaximumequivalentstressmax=723.1MPa,whichis27%less.TheoptimumresultsareshowninTable4.Table4OptimizationprocessIterationtimes1234567891011R1/mm75.00081.94377.35880.85567.24980.44167.36565.59165.18465.17265.067R2/mm88.00088.22995.26190.47889.53589.98393.66182.79193.75380.60480.153H/mm80.00071.64060.10080.85489.68474.32781.40965.29761.47884.95588.6271/()30.00033.84729.38221.40032.63336.08531.81637.64439.47433.86134.0522/()30.00030.75126.40626.94623.01836.72921.26720.32524.74020.11320.058max/MPa1066.51167.41323.21229.7882.51241.7882.4866.8943.9756.0749.7Iterationtimes12131415161718192021R1/mm65.04865.04765.04865.04865.04765.04865.04865.04365.04265.042R2/mm80.07080.06393.50683.63384.98780.07080.06580.04580.04480.045H/mm65.80885.14188.11687.94588.97889.59889.59689.86766.84089.8391/()30.58532.45635.41427.78633.23123.14430.64230.25027.55631.3412/()23.47922.21420.04435.94120.04620.04520.04520.04220.04220.042max/MPa780.0769.6760.4788.0769.0795.8723.1741.3821.3751.34Conclusions1)BasedonANSYSsoftware,itsseconddevelop-mentlanguageAPDLwasusedtodevelopa3-Dmodelofthehotextrusiondiethatextrudesaluminiumprofilehasbeenobtained.2)The3-Dstressdistributionwasveryuneven,withseverestressconcentrationsinthebridgeofthehotex-trusiondie.Theoptimalgeometricdesignhad27%lowermaximumstress,Abetterdiewillnotonlyre-ducedienumberbutalsoreducetimelostchangingdies,whichwillgreatlyheightenproductivity.References1YinJianhua.Structuraladjustmentorientationfordomesticlarge-scaledaluminumprocessingenterprisesintermsofimportsituationofaluminummaterialinrecentyears.TheWorldNon-FerrousMetal,2001,10:37-42.(inChinese)2LiYi.Forecastondomesticaluminummaterialconsump-tionandadvicesonoptimizingdomesticaluminummate-rialindustryconstitution.JournalofSouthernInstituteofMetallurgy,2002,4:305-308.(inChinese)3YiMiao,LiuFang.Thecontributingfactorsanalysisaboutthelifespanoftheextrusiondie.LightAlloyProcessTechnology,2000,28: