沖壓工藝中幾何及內(nèi)圓角對(duì)模具應(yīng)力產(chǎn)生的影響-畢業(yè)論文外文翻譯

1、1附錄附錄A外文文獻(xiàn)外文文獻(xiàn)EffectsofgeometryfilletradiusondiestressesinstampingprocessesAbstract:Thispaperdescribestheuseofthefiniteelementmethodtoanalyzethefailureofdiesinstampingprocesses.Fthedieanalyzedinthepresentproblemthecracks

2、atdifferentlocationscanbeattributedtoacoupleofmechanisms.Oneofthemisduetolargeprincipalstressestheotheroneisduetolargeshearstresses.Athreedimensionalmodelisusedtosimulatetheseproblemsfirst.Themodelisthensimplifiedtoanaxi

3、symmetricproblemfanalyzingtheeffectsofgeometryfilletradiusondiestresses.2000ElsevierScienceS.A.Allrightsreserved.Keywds:StampingMetalfmingFiniteelementmethodDiefailure1.IntroductionInmetalfmingprocessesdiefailureanalysis

4、isoneofthemostimptantproblems.Befethebeginningofthisdecademostresearchfocusedonthedevelopmentoftheeticalnumericalmethods.Upperboundtechniques[12]contactimpactprocedures[3]thefiniteelementmethod(FEM)[45]arethemaintechniqu

5、esfanalyzingstampingproblems.WiththedevelopmentofcomputertechnologytheFEMbecomesthedominanttechnique[612].Altancowkers[1314]discussedthecausesoffailureinfgingtoolingpresentedafatigueanalysisconceptthatcanbeappliedduringp

6、rocesstooldesigntoanalyzethestressesintools.Inthesetwopaperstheyusedthepunchingloadastheboundaryfcetoanalyzethestressstatesthatexistinthesduringthefmingprocessdeterminedthecausesofthefailures.Basedontheseconceptstheyalso

7、gavesomesuggestionstoimprovediedesign.Inthispaperlinearstressanalysisofathreedimensional(3D)diemodelispresented.Thestresspatternsarethenanalyzedtoexplainthecausesofthecrackinitiation.Somesuggestionsaboutoptimizationofthe

8、dietoreducethestressconcentrationarepresented.Indertooptimizethedesignofthedietheeffectsofgeometryfilletradiusarediscussedbasedonasimplifiedaxisymmetricmodel.2.Problemdefinition3FthetwomeshesusedinCase1.Themaximumprincip

9、alshearstress(S12)distributionattheregionoffilletareshowninFig.4ab.Theresultsshowthatthestressdistributionpatternsarethesamefthetwodifferentmeshestherefetheconvergenceofthesolutionsisestablished.Altancowkers[14]haveprese

10、ntedthestressanalysisofanaxisymmetricupperdie.Intheirwkwhenthematerialofthewkpieceflowstofillthevolumebetweenthediescollarthecontactsurfaceofthedieisstretched.Attheareaofthetransitionradiustheprincipalstresseschangedirec

11、tionreachhightensilevalues.Accdingtotheiranalysisthefatiguefailureisduetotwofacts:(i)whenthestressexceedstheyieldstrengthofthediematerialalocalizedplasticzonegenerallyfmsduringthefirstloadcycleundergoesplasticcyclingduri

12、ngsubsequentunloadingreloadingthusmicroscopiccracksinitiate(ii)tensileprincipalstressescausethemicroscopiccrackstogrowleadtothesubsequentpropagationofthecracks.TheVonMisesstressdistributionisshowninFig.5a.Veryhighstresso

13、ccurinthehalfmoonfilletregions.Ifthecontactpressurekeepsincreasingplasticzoneswillfmfirstinthesetworegions.Fig.5bshowsthemaximumprincipalstress(SP3)distributionpattern.IndertoshowtheareaofCrackIinitiationFig.5cprovidesaz

14、oomedviewofthearea.Itisclearthatatensileprincipalstress(SP3)concentrationof25.5MPaexistsbetweenthehalfmoonpatternthefreeedgeisthecauseofcrackinitiation.SinceCrackIpropagatesnearlynmaltothe12planethedirectionofthestresses