航空薄壁件精密铣削加工变形的预测理论及方法研究

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1、浙江大学机械与能源工程学院博士学位论文航空薄壁件精密铣削加工变形的预测理论及方法研究姓名：白万金申请学位级别：博士专业：机械制造及其自动化指导教师：柯映林;董辉跃20081201浙江大学博士学位论文关键词：薄壁件；数控铣削加工：加工变形；局部弹性变形；有限元模拟；切削力；切削温度；热力耦合；加工稳定性；残余应力本论文研究得到了国家自然科学基金重点项目(50435020)及国家863高技术研究发展计划(2006AA042147)的资助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，

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