缺口件振動(dòng)疲勞壽命分析的名義應(yīng)力法.pdf

1、南京航空航天大學(xué)碩士學(xué)位論文缺口件振動(dòng)疲勞壽命分析的名義應(yīng)力法姓名：李德勇申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：飛行器設(shè)計(jì)指導(dǎo)教師：姚衛(wèi)星201101缺口件振動(dòng)疲勞壽命分析的名義應(yīng)力法IIAbstractFengineeringstructuresofaerospacetransptationwhichbearvibrationloadingfatiguefailureisoneofthemainfailuretypes.Thestressconce

2、ntrationatnotchrootiscriticalinantifatiguedesignofstructure.Thusthestudyofvibrationfatiguelifefnotchcomponentshasimptanttheeticalsignificancepracticalvalue.Thefrequencydomainanalysisofvibrationfatiguehasbeenreviewedsyste

3、maticallyinthisthesis.Twodynamicstressconcentrationfactsweredefinedinthisthesis.Thestaticmodalfrequencyresponseromvibrationanalysisofnotchcomponentswereaccomplished.Thenthedefinitioncalculationfmulaofdynamicstressconcent

4、rationfactwereproposedaccdingtothepeakofpowerspectraldensityatthemostdangerouspoint.Thedefinitioncalculationfmulaofthemeansquarestressconcentrationfactwereproposedbasedontherootmeansquareofstressofhotpoint.Twoexampleswer

5、ecarriedouttheresultsprovedthatthesefmulascoulddescribethestressconcentrationofnotchcomponentsundervibrationloadconditionswell.Anominalstressapproachwaspresentedtopredictthevibrationfatiguelifeofnotchedcomponentsinthisth

6、esis.Basedonthebasicmechanismoffatiguethedistributionacteristicsofstressstressmeansquarevaluearoundnotchofgroovenotchedplateswerestudied.Consideringdistributionacteristicsofstressmeansquarevalueindangerousregionaroundthe

7、notchthefmulasfnotchfatiguefactunderdifferentdistributionacteristicsweregivenseparatelyusingmeanstressmodel.Consequentlythenominalstressapproachflifepredictionofnotchedcomponentsundervibrationloadingwasobtained.Throughtw

8、otypicalexamplesitcanbeshownthattheproposedmethodinthisthesiswascompetentenoughtopredictthevibrationfatiguelifeofnotchedcomponents.Keywds:vibrationfatiguefrequencydomainmethodtheeticalstressconcentrationfactmeansquarestr