搜索
OnlineExercises–Lecture822.5914–Fall2014Question1:AluminumBeamAbeamwitharectangularcrosssectionhasdimensionsofb=40andt=20mm.Thebeamismadeof7475-T7351aluminumandissubjectedtoabendingmomentofM=900N.m.a.Ifathrough-thicknessedgecrackoflengtha=4mmispresent,whatisthesafetyfactoragainstbrittlefracture?b.Repeata)foracracklengthof20mm.c.Whatisthecriticalcracklengthforfracture?d.Whatcracklengthcanbeallowedisasafetyfactorof3.0againstbrittlefractureisrequired?e.Forthecracklengthfoundind),whatisthesafetyfactoragainstfullyplasticyielding?Question2:FailureforAluminumThecombinationsofcracklengthandstresscorrespondingtofailureinFigure8.5aregiveninTable1.Table1:Failuredatafor2024-T6DataNumberCracklengthac,mmStressatFractureSg,MPa13.045325.35405310.70342418.43276534.60202662.19142a.Plotthesedata,thelineforσ0=518MPa,andthecurveforKc=66MPa.m0.5,justastheyappearinFigure8.5b.AlsoplotarevisedcurveforKc=66MPa.m0.5wheretheplasticzoneadjustmentisused.c.Commentonthesuccessofcurve(b)inpredictingthebehavior..