冲孔复合模-英文翻译

沈阳工业大学工程学院毕业设计（论文）外文翻译毕业设计（论文）题目：冲孔复合模模具设计与虚拟制造外文题目：Diedesignforstampinganotebookcasewithmagnesiumalloysheets译文题目：笔记本上盖外壳的镁合金薄板冲压模具设计系（部）：机械系专业班级：材料成型及控制工程学生姓名：董渊博指导教师：张国宏2011年10月30日DiedesignforstampinganotebookcasewithmagnesiumalloysheetsContentSummaryInthepresentstudy，thestampingprocessformanufacturinganotebooktopcovercasewithLZ91magnesium–lithiumalloysheetatroomtemperaturewasexaminedusingboththeexperimentalapproachandthefiniteelementanalysis.Afour-operationstampingprocesswasdevelopedtoeliminateboththefractureandwrinkledefectsoccurredinthestampingprocessofthetopcovercase.Inordertovalidatethefiniteelementanalysis，anactuafour-operationstampingprocesswasconductedwiththeuseof0.6mmthickLZ91sheetastheblank.Agoodagreementinthethicknessdistributionatvariouslocationsbetweentheexperimentaldataandthefiniteelementresultsconfirmedconfirmedtheaccuracyandefficiencyoftheementanalysis.ThesuperorformabilityofLZ91sheetatroomtemperaturewasalsodemonstratedinthepresentstudybysuccessfulmanufacturingofthenotebooktopcovercase.Theproposedfouroperationprocesslendsitselftoanefficientapproachtoformthehingeinthenotebookwithlessnumberofoperationalproceduresthanthatrequiredinthecurrentpractice.ItalsoconfirmsthatthenotebookcovercasescanbeproducedwithLZ91magnesiumalloysheetbythestampingprocess.Itprovidesanalternativetotheelectronicsindustryintheapplicationofmagnesiumalloys.Keywords:Notebookcase；LZ91magnesium–lithiumalloysheet；stamping；Multi-operation；Formability1.IntroductionDuetoItslightweightandgoodperformanceinEMIresistance,magnesiumalloyhasbeenwidelyusedforstructuralcomponentsintheelectronicsindustry,suchascellularphonesandnotebookcases.Althoughtheprevailingmanufacturingprocessofmagnesiumalloyproductshasbeendiecasting，thest-ampingofmagnesiumallsheethasdrawninterestsfromindustrybecauseofitscompetitiveproductivityandperformanceintheeffectiveproductionofthin-walledstructuralcomponents.Asforstampingprocess，AZ31magnesiumalloy(aluminum3%,zinc1%)sheethasbeencommonlyusedfortheformingprocessatthepresenttime,eventhoughitneedstobeformedatelevatedtemperatureduetoitshexagonalclosedpacked(HCP)crystalstructureRecently,themagnesium–lithium(LZ)alloyhasalsobeensuccessfullydeve-lopedtoimprovetheformabilityofmagnesiumalloyatroomtemperature.Theductilityofmagnesiumalloycanbeimprovedwiththeadditionoflithiumthatdevelopstheformationofbodycentered-cubic(BCC)crystalstructure(Takudaetal.,1999a,b;Drozdetal,2004).Inthepresentstudy,thestampingprocessofanotebooktopcovercasewiththeuseofLZsheetwasexamined.Theformingofthetwohingesinthetopcoverofanotebook,asshowninFig.1(aandb),isthemostdifficultoperationinthestampingprocessduetothesmalldistancebetweentheflangesandthesmallcornerradiiattheflanges,asdisplayedinFig.1(c).Thisgeometricomplexitywascausedbyadramaticchangeinthecornerradiuswhentheflangeofgetstooclosetthenotebook,whichwouldeasilycausefracturedefectaroundtheflangeofhingeandrequireamulti-operationstampingprocesstoovercomethisproblem.Inthepresentstudy,theformabilityofLZmagnesiumalloysheetswasinvest-igatedandanoptimummulti-operationstampingprocesswasdevelopedtoreducethenumberofoperationallprocedusingboththeexperimentapproachandthefiniteelementanalysis.Fig.1–Flangeofhingesatnotebooktopcovercase.(a)Hinge,(b)topcovercaseand(c)flangesofhinge.2.Mechanicalpropertiesofmagnesiumcontentoflithiumincreases.ItisalsoobservfromFig.2(a)thatthecurvesofLZ91sheetatroomtemperatureandAZ31sheetat200,Careclosetoeachother.LZ101sheetatroomtemperatureexhibitsevenbetterductilitythanLZ91andAZ31doat200,C.Sincethecostoflithiumisveryexpensive,LZ91sheet,insteadofLZ101sheet,canbeconsideredasasuitableLZmagnesiumalloysheettorenderfavorableformabilityatroomtemperature.Forthisreason,thepresentstudyadoptedLZ91sheetastheblankforthenotebooktopcovercaseandattemptedtoexaminetheformabilityofLZ91atroomtemperature.Inordertodetermineifthefracturewouldoccurinthefiniteelementanalysis,theforminglimitdiagramforthe0.6mmthickLZ91sheetwasalsoestablishedasshowninFig.2(b).alloysheetsThetensiletestswereperformedformagnesium–lithiumalloysheetsofLZ61(lithium6%,zinc1%),LZ91,andLZ101atroomtemperaturetocomparetheirmechanicalpropertiestothoseofAZ31sheetsatelevatedtemperatures.Fig.2(a)showsthestress–strainrelationsofLZsheetsatroomtemperatureandthoseofAZ31sheetsatbothroomtemperatureand200?C.Itisnotedthatthestress–straincurvetendstobelower.Fig.2–Mechanicalpropertiesofmagnesiumalloy.(a)Thestress–strainrelationsofmagnesiumalloy;(b)forminglimitdiagram(FLD)ofLZ91sheet.3.ThefiniteelementmodelThetoolinggeometrieswereconstructedbyaCADsoftware,PRO/E,andwereconvertedintothefiniteelementmesh,asshowninFig.3(a),usingthesoftwareDELTAMESH.Thetoolingwastreatedasrigidbodies,andthefour-nodeshellelementwasadoptedtoconstructthemeshforblank.Themateriallpropertiesandforminglimitdiagramsobtainedfromtheexperimentswereusedinthefiniteelementsimulations.Theothersimulationparametersusedintheinitialrunwere:punchvelocityof5mm/s,blank-holderforceof3kN,andCoulombfrictioncoefficientof0.1.ThefiniteelementsoftwarePAMSTAMPwasemployedtoperformtheanalysis,andthesimul