已阅读5页,还剩12页未读, 继续免费阅读
版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领
文档简介
OptimizationofDieDesignforForgingaTurbo-ChargerImpellerandaRingGearUsingProcessSimulationJayGunasekera,PhD,DSc,PE,ProfessorofMechanicalEngineering,OhioUniversity,USA,MazyadAl-MoheibandFahadAl-Mufadi,FormerPhDstudentsatOhioUniversity,USASYNOPSIS:Theobjectiveofthisprojectwastooptimizethepreformandfinaldiedesignfortwocomplexautomotiveforgedproducts(aturbineimpellerandaringgear)fortwodifferentforgingcompaniesintheUS.Theturbineimpellerhastohaveaminimumeffectiveplasticstrainof0.5inordertoincreasethetoughnessandresistfractureduetotheveryhighcentrifugalstresses.Itisalsoimportanttodistributethestrainandthegrainsizeasuniformlyaspossiblethroughoutthefinishedforgedpart,soastoachievethebestmechanicalpropertiesfortheAl2618turbinewheel.Optimizationofgrainsizewasperformedbydeterminingoptimaltemperatureandaveragestrainrate(bytheuseofZener-HollomonParameter).ThesecondprojectwastooptimizethediedesignforasteelRingGear,soastoreducethenumberofforgingstagesandalsoreducethematerialwastageduetoexcessiveflash.ThesoftwareusedwasMSC.SuperForge,thepredecessorofSimufact.forming,whichiscapableofcheckingthediefilling,defectformationanddiecontactinthefinalstage.Itcanalsodetermineanddisplayavarietyofusefulparameterssuchas;theeffectiveplasticstrain,effectivestrainrate,effectivestress,materialflow,temperature,force-timerelationshipandfinalshapebyusingSuperforge-FV(FiniteVolume)simulation.Itisconcludedthatthesoftwarecanbeeffectivelyusedtooptimizetheforgingprocesstomaximizethemechanicalstrength,minimizematerialscrap&forgingstagesandhencereducetheoverallcostofmanufacture.1.INTRODUCTION:Theobjectiveofthisprojectwastooptimizethepreformandfinaldiedesignfortwocomplexautomotiveforgedproducts.Thefirstpartisaturbo-chargerimpeller(orturbinewheel)madeofaluminum.Thispartrotatesatveryhighspeed(upto100,000RPM),acceleratesrapidlyfromrestandhasveryhighcentrifugalstresses.Thenewpreformdieshavetobedesigned,sothattheeffectiveplasticstraininthedeadmetalzoneofthispartcanbeincreasedtoavaluegreaterthan0.5.Theyieldstrengthcanalsobeincreasedbytheoptimizationofthenewpreformdiedesignsinceitincreasestheloweffectiveplasticstraininthedeadmetalzone.Thisalsoleadstoanearuniformeffectiveplasticstrainthroughouttheformedproduct.ReferringtoFigure1,itcanbeseenthataflatpreformdiewaspreviouslyusedintheforgedrotatingpartwithalloyAA2618.ReferringtoFigure2,adiewiththefinalcontourwasusedtoobtainaneffectiveplasticstraingreaterthan0.5inthefinalproduct.However,thisdoesnotresultinanoveralluniformplasticstraingreaterthan0.5.AproblemassociatedwiththisproductisthepresenceofloweffectiveplasticstrainwhichisdisplayedinFigures1and2bytheregionsofblueknownasDeadMetalZone(DMZ)1.Figure1StraincontourswithflatdieFigure2FinalstraincontourswithflatdieThegoalistoachievethebestmechanicalpropertiesthroughouttheforgedrotatingpartmadefromAA2618.Themainadvantageofthehotforgingoperationisgainedbydecreasingtheinhomogenitiesoftheworkpiece;porositiesareeliminatedbecauseoffusionofcavities.AnothergoalistheoptimizationoftheZener-Hollomanparameter,Z,bydetermininganoptimaltemperatureandanaveragestrainrate,inordertogetanindicationofthegrainsizeofthematerial.TheZenerHollomanparameterincreaseswithanincreaseintheaveragestrainrateandtheaveragestrainrateincreaseswithanincreaseintheeffectiveplasticstrainordecreaseinforgingtime.Itisalsoincreasedbyadecreaseintheforgingtemperature.Thecoarsecolumnargrainsarereplacedbysmallerequiaxed,recrystallizedgrainsthatgiveanincreaseinductilityandtoughness.Thiswoulddecreasethestrengthinadirectforging,but,apreformwherethemagnitudeofthestrainhasbeenincreasedwouldpreservethestrengthofthematerial.Thesecondpartisaringgear2,andtheobjectiveherewastoreducethenumberofforgingstagesandalsoreduceanymaterialwastage.FEMforwardsimulationhasplayedasignificantroleinpredictingthedeformationflowpatternsandhasimprovedthequalityoftheproduct.However,themainroleofFEMistoverifythediedesignsaccomplishedbyusingempiricalrelationshipsorbasedonengineeringpractice3.Usually,anumberofpreformsareneededinordertoachievethefinalcomplexshapefromtheinitialsimpleshapewiththeoptimalpropertiesandgeometricaltoleranceinmetalformingprocesses.Forgingpreformdesignisdeterminedviabackwarddeformationsimulationsusingaproceduresimilartodiedesignprocedurewherethedieshapesandprocessparametersaredeterminedbasedonthefinalproductshapeaswellasthematerialpropertiesrequirements.Consequently,forgingpre-formdesignprocessusingbackwardsimulationhasaveryimportantfunctioninforgingdiedesignprocess.Optimizingtheentireforgingprocesstoobtainthedesiredforgingpropertiessuchasachievingproperdie-fill,reducingthematerialwaste,reducingthediewear,obtainingfavorablegrainflowandtheloadrequiredcanbefulfilledbyusingadequateandappropriatepre-forms3.UBET(UpperBoundElementTechnique)wasusedforthebackwardsimulationtoobtainanoptimalperformandthenFiniteVolumeMethod(Simufact.formingsoftware)wasusedtodotheforwardsimulationandverifythedesign.UBEThasbeendevelopedandusedbymanyresearchers;forexampleLeeetal.4usedUBETtoanalyzetheforgingload,diefilling,andtheeffectivestrainforforgingswithandwithoutflashgap.Theprogramwasappliedtobothaxisymmetricandnon-axisymmetriccloseddieforgingaswellasplanestraincloseddieforgingwithrib-webtypecavity.Theresultsobtainedfromthisstudywerecomparedwithexperimentalresultsinwhich,agoodagreementwasachieved.Apre-formdesignapproachthatincorporatesbothFEM-basedforwardsimulationsandUBET-basedbackwardsimulationswasdevelopedbyLiu,etal.5.Bramley,6,hasemployedTEUBA,whichisaUBET-basedcomputerprogramfortheprocessofforgingpre-formdesignusingreversesimulations.Thisapproachisbasedonreversingtheflowbystartingfromthedesiredfinalshapewiththedievelocitiesreversedinsuchawaythatthematerialattheendofthedeepestdiecavityisconsideredtohaveafreeboundaryandmaterialflowsbackwarduptocertaintimestepwherethediesareseparatedfromthebillet,whichgivesthepre-formoftheprocess.Afiniteelement-basedinversediecontacttrackingmethodtodesigntheperformdieshapesofagenericturbine-diskforgingprocesswasusedbyZhao,etal.7.Finally,M.MohelibandJ.S.Gunasekera8usedUBETforbackwardsimulationinRingRollingandforforgingaRingGear.TheRingGearprojectisreportedinthispaper.ThetheoryofUBETcanbefoundinanumberofexcellentpublicationsandwillnotberepeatedhere.2.TURBINEWHEELANALYSIS1ThedevelopmentofFiniteElementAnalysis(FEA)techniqueshasprovidedanimportantlinkbetweenadvancesindieandequipmentdesignandanimprovedunderstandingofmaterialsbehavior.InputstotheFEcodesincludethecharacteristicsoftheworkpiecematerial(flowstressandthermalproperties)andthetool/workpieceinterface(frictionandheattransferproperties),aswellasworkpieceandtoolinggeometries.Typicaloutputsincludepredictionsforformingload,strain,strainrateandtemperaturecontourplots,andtoolingdeflections.Themethodofstudyforthismodelis:1.ThemodelsarefirstmadeinCADsoftwaresuchasSOLIDEDGEforthebilletsandforpreform(upsettingdies)aswellascloseddieforginginboththeupperandlowerdies.Thismodelisexportedforthree-dimensionalFEAtechniquessuchasFV(FiniteVolume)analysis(simulation)ofactualdieforgingoftherotatingpartwithSUPERFORGE9tofindflawsinthedesignofthepreform.2.Tofocusonoptimizingthepreformdesign.3.Todefinethebestpreformdesignandfinishedworkpiecebasedonoptimizationresultsandtoverifytheapplicabilityofthismethod.Oneofthemostimportantaspectsoftheclosed-dieforgingprocessisthedesignofpreforms(orblockers)toachieveadequatemetaldistribution.Withtheproperpreformdesign,defect-freemetalflowandcompletediefillcanbeachievedinthefinalforgingoperationandmetallossesintoflashcanbeminimized.Thedeterminationofthepreformconfigurationisanespeciallydifficulttaskinvolvingthoroughmetalflowunderstanding.The3DmodelingsoftwareSolidEdgeisusedtomodelparts,billetsanddies.SolidEdgehasanoptionbywhichvolumeofthemodeledpartcanbefound.SolidEdgeprovidestheoptionofBooleanoperationbywhichaspecificshapecanbesubtractedoraddedtoanothershape.Forthisresearch,lower-dieandupper-diearemodeledwithoutBooleanoperations.SimufactSUPERFORGEisusedtosimulatetheforgingprocess.3.FINITEVOLUMEMETHODThetraditionalfiniteelementmeshdistortswhenaneffortismadetotrackthedeformationofthematerial.However,whenthefinitevolumemethodisused,thecomputationalmeshusesafinitevolumemeshwithanunchangingframeofreferencewhenthematerialofthebilletflowsthroughthemesh.Theenergy,themassandthemomentumofthematerialaretransportedfromonecomponenttoanother.Thegridpointsforthefinitevolumesolverarepresetinspaceandtheelementsarejustpartitionsofthespacedefinedbytheconnectedgridpoints.Thematerialofthebilletbeneathanalysismovesthroughoutthefinit
温馨提示
- 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
- 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
- 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
- 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
- 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
- 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
- 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
最新文档
- 平移与旋转练习题(有标准答案)
- 公共危机管理导论心得
- 《二氧化碳作业设计方案-2023-2024学年科学浙教版2013》
- 《蚕宝宝出生了》导学案-2023-2024学年科学湘科版2001
- 《石头与住房导学案-2023-2024学年科学鄂教版2001》
- 2016秋新版-浙大远程-电子技术基础-离线作业答案-第一篇-第2章习题(文档良心出品)
- 《动物与能量导学案-2023-2024学年科学冀人版》
- 《口语交际-应对作业设计方案-2023-2024学年初中语文统编版五四学制》
- 《寄生虫污染及控制导学案-烹饪营养与安全》
- 《我们的情感世界》导学案-2023-2024学年初中道德与法治统编版
- 云南省2021年《医学综合》专升本真题试卷含答案
- 新标准日本语初级上册练习题与答案详细
- 新版国家自然基金申请代码
- 妇科疾病诊疗指南
- 2019美国冠状动脉非阻塞型心肌梗死科学声明
- FusionCloud私有云最佳实践Region Type I
- 行业类别代码表
- 三年级数学下册苏教版《简单的数据汇总》课件(校际公开课)
- GSP药品批发企业终止妊娠药品管理制度
- DB43∕T 1423-2018 循环运动式育苗设备
- 输油管道同沟敷设光缆设计、施工及验收规范
评论
0/150
提交评论