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1、浙江大學(xué)機(jī)械與能源工程學(xué)院博士學(xué)位論文航空薄壁件精密銑削加工變形的預(yù)測理論及方法研究姓名:白萬金申請學(xué)位級別:博士專業(yè):機(jī)械制造及其自動化指導(dǎo)教師:柯映林;董輝躍20081201浙江大學(xué)博士學(xué)位論文關(guān)鍵詞:薄壁件;數(shù)控銑削加工:加工變形;局部彈性變形;有限元模擬;切削力;切削溫度;熱力耦合;加工穩(wěn)定性;殘余應(yīng)力本論文研究得到了國家自然科學(xué)基金重點(diǎn)項(xiàng)目(50435020)及國家863高技術(shù)研究發(fā)展計劃(2006AA042147)的資助Ⅱ摘要ABSTRACTAtpresent,airframesarewidelymadeofmonolithicthin‘walledc
2、omponentsforthesakeofweightreducingandstrengthratioimprovement.However,duetofactorssuch勰cuttingforceinducedflexibledeflection,dynamicvibrationandnon-uniformresidualstressdistributioninduceddistortion,precisionmachiningoftheselow-rigiditythin-walledpartshasbeenprovidingaseriouschalleng
3、eforengineers.Inthisarticle,themodelsandmethodsforpredictingtheprecisionmillingdeformationerrorsaresystematicallyinvestedbymeansoftheoreticanalysis,mechanicsmodeling,fiuiteelementsimulationandexperimentsverification.Firstly,basedonlargedeformationtheoryandvirtualworkprinciple,athree—d
4、imensional(3-D)themao-elastic—plasticcoupledfiniteelementanalysis(FEA)modelisconstructedtoinvestigatethehigh—speedmilling(HSM)processesof7050-T7451aluminumalloy.SeveralkeyFEAtechniques,such弱finiteelementmeshmodel,materialconstitutivemodel,chipseparationcriteria,frictionsonthetool-chip
5、interfaceand3-Dheatconductiongoverningequations,areanalyzedandimplementedtoimprovetheaccuracyandefficiencyoftheFEAsimulation.AHSMcaseissimulatedwiththe3一DFEAmodel.Thedetailedcalculatedresultsarepresentedandanalyzed,includingthechip’Sgeometricshapeanditsevolutionprocesses,thestress,str
6、ain,cuttingforces,andtemperaturedistributionsintheworkpiece,toolandchip,弱well弱theresidualstressesdistributionsonthemachinedsurface.Secondly,basedontwotypicalcuttingforcepredictingmodels,namelytherigidmodelandtheflexiblemodel,anumericalsimulationprocedureisdevelopedtoevaluatecuttingfor
7、cesunderdifferentcuttingconditions.Theprecisionandvalidityofthepredictionmodelsareverifiedbythemillingforceexperimentalmeasurements.Then,asemi—artificialthermocoupledeviceisdevelopedtoexplorethedynamiccuttingtemperaturevariationrulesinhigh—speedmillingofA17050·T7451aluminumalloy.Also,
8、acutt