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《噴丸殘余應力場與三維次表面裂紋應力強度因子求解》由會員上傳分享，免費在線閱讀，更多相關(guān)內(nèi)容在行業(yè)資料-天天文庫。
1、上海交通大學碩士學位論文應力強度因子在數(shù)值上要小于表面裂紋的應力強度因子，即殘余應力場對萌生于材料表面的裂紋擴展速率的影響更為明顯。次表面裂紋靠近有限邊界的前緣對應力變化以及距離邊界的尺寸的變化更為敏感。關(guān)鍵詞：應力強度因子，次表面裂紋，三維權(quán)函數(shù)，殘余應力，噴丸II萬方數(shù)據(jù)上海交通大學碩士學位論文RESIDUALSTRESSESANDTHREEDIMENSIONALSTRESSINTENSITYFACTORSOFSUBSURFACECRACKSFORSHOT-PEENED-MATERIALSABSTRACTAst
2、hemostusefulmethodtoimprovethesurfaceconditionsandincreasethefatiguelifeformaterialsandstructures,shot-peeninghasbeenwidelyusedinthedesignofaerospaceandautomobilecomponents.Themainmechanismofshot-peeningistheintroductionofresidualcompressivestressfield,whichca
3、nchangethecrackinitiationlocationsanddecreasethecrackpropagationrate.Thus,quantitativestudyoftheresidualstressesandthestressintensityfactorsaftershot-peeninghasbeenanimportantsubjectintheoreticalandpracticalfield.Firstly,withthecomparisonbetweenthepredictionsa
4、ndtestresultsofvariousshot-peenedmetals,thecapabilityoffivesolutionsincludingempiricalequations,theoreticalmodelsandFEMmodelsforpredictingthecharacteristicparametersofresidualstressfieldwasproved.TheempiricalequationsofYaohadgoodpredictionsfor40Crsteelandother
5、similarsteels，andtheempiricalequationsofWangwerecapableofvariousmetalswhiletheoreticalmodelsweresuitableformetalswithmediumstrengthandhardeningrate.Thepredictingresultsofsingle-shotFEMmodelsforcalculatingthepeeningdentsdiametersandmulti-shotFEMmodelsforcalcula
6、tingtheresidualstressfieldwereingoodagreementwithtestresultsofvariousmetalswithdifferentshot-peeningcoverage.Inpractice，combinationsofthesemethodswereneeded.Secondly,tostudythebehaviorandthethreedimensionalstressintensityfactorsofsubsurfacecracks,thecrackbodyw
7、asconsideredasellipticalcrackanddecomposedintotwokindsofslips,thatistheIII萬方數(shù)據(jù)上海交通大學碩士學位論文fundamentalslipswithmulti-collinearcracksfeaturesandtheelastic-springslipswitheccentriccracksfeatures.Basedonthethreedimensionalweightfunctiontheory,thethreedimensionalwe
8、ightfunctionsofthesubsurfaceellipticalcrackswereachieved.Finally,onthebasisofthethreedimensionalsubsurfaceweightfunctions,thestressintensityfactorsofthe40Crsteelaftershot-peeningwe
