外文翻译--热挤压模具的优化设计-精品.doc
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StressAnalysisandOptimumDesignofHotExtrusionDies
Abstract:
Athree-dimensionalmodelofahotextrusiondiewasdevelopedbyusingANSYSsoftwareanditsseconddevelopmentlanguage—ANSYSparametricdesignlanguage.Afiniteelementanalysisandoptimumdesignwerecarriedout.Thethree-dimensionalstressdiagramshowsthatthestressconcentrationisrathersevereinthebridgeofthehotextrusiondie,andthatthestressdistributionisveryuneven.Theoptimumdimensionsareobtained.Theresultsshowthattheoptimumheightoftheextrusiondieis89.596mm.Theoptimumradiiofdiffluenceholesare65.048mmand80.065mm.Thestressconcentrationisreducedby27%.
Keywords:
three-dimensionalmethod;modeling;hotextrusiondie;optimumdesign
Introduction
Withthecontinuousimprovementoflivingstandards,betterthermalconductivityofaluminumalloyprofiles.Aluminumcomponentswidelyusedineveryaspectoflife.Therefore,thealuminumalloyextrusionprofiles,profilesofvarioustypesofradiatorshavebeenwidelyusedinelectricalappliances,machinery,andotherindustries.Variableproductsandthegrowingdiversityandcomplexityofhigh-precision,theextrusionprocessisthebasisforextrusiondie.Itnotonlydeterminestheshape,size,accuracyandsurfacestate,butalsoaffecttheperformanceoftheproduct.Soextrusiondieextrusiontechnologyisthekey.
Studiestoimproveextrusiondiequalityandprolongitslifespanusuallyattempttosimplify3-Dfiniteelementmodelto2-D,butitisonlyrightforsimplestructuralshapes.Withouta3-Dfiniteelementanalysis,theresultscannotgivepracticalmanufacturinghelpandofferusefulinformation[3-5].Inthispaper,aluminiumprofileextrusiondiewasmodeledtogetinoptimumdesign[6-8].
1SolidModeling
Figure1showsthemaledieofahotextrusionplanarcombineddie.Itsexternaldiameteris227.000mm,itsheightis80.000mm.OtherparametersareshowninFig.1.Themodelingmethodisasfollows.
1.1CoordinatesofP1andP5
ThecoordinatesofthepointofintersectionbetweenthebeelineL(y=kx+b)andthecirculararc(x2+y2=R2)are
1.2CoordinatesofP2andP6
Thecoordinatesoftheintersectionpoint(P2)betweenbeelineL1(y=kx+b)andbeelineL2(y=S1)are
Thecoordinatesoftheintersectionpoint(P6)betweenbeelineL3(y=kx+b)andbeelineL4(y=S1)are
1.3CoordinatesofP3,P4,P7,andP8
P3andP1aresymmetricaboutthey-axis.P4andP2arealsosymmetricaboutthey-axis.P7andP5aresymmetricaboutthex-axis.P8andP6arealsosymmetric
aboutthex-axis.
1.4Variablesintheequations
InEqs.
(1)-(6),forpointsP1andP2,andR=R1.ForpointsP5andP6,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),z€[0,H].
1.5Sectionshapeatsomeheight
WithlineslinkingP1-P4,P5-P8,withcirculararcfilletingatthepointofintersection(P1-P8),thesectionshapeatsomeheightisobtained.
1.6Sectionshapeateveryheight
Hisdividedtointerfacialnumber(INUM)equalparts(INUMisdecidedbytheprecision,iftheINUMishigher,theprecisionisbetter).ThesectionshapeisdrawnateveryheightasshowninFig.2.
1.7Smoothcurvedsurface
UsingSKINcommandinANSYS,smoothcurvedsurfaceswerebuiltalongthelines.Theyarethesurfacesoftheinfluencehole.UsingtheVA(itgeneratesavolumeboundedbyexistingarea)command,asolidwascreatedfromthosesurfaces.
1.8Symmetryofthedie
ThemainbodyandkernelofthedieweredrawnusingtheBooleanoperationsofadd,subtract,etc.(Fig.3).Thesymmetryofthediewasusedtoacceleratethecomputationsusinga1/4-solidmodelforthefiniteelementanalysis(Fig.4).
2ComputingModel
Aplanardiethatextrudesthealuminiumalloy(6063Al-Mg-Si)wasusedasanexample.TheliquidoidofAlis657℃[9],andthemelttemperatureofAl+Mg2Siis558℃.Takingtheextrusionpressureandtheproductsqualityintoaccount,theworkingtemperaturewasdeterminedtobe450℃.
Thediematerialis4Cr5MoSiV1(H13).Belowthe450℃,itsYoungmodulusandPossionratioare210GPaand0.25,respectively.Itsyieldstrengthis1200MPa.Thefrictioncoefficientis0.3.TheSolid923-Dsolidelementwasusedtocarrythroughthefreemesh.Inordertoloadthefrictionalforcewhileextruding,thesurfaceeffectelementSurf154wasusedtoproducetheregularquadrangles(Fig.5).Forthe1600textruder,theextrusionintensitywascomputedusingEq.(7)[10].ThevaluesareshowninTable1.
Thebridgecollapseo