材料力学智慧树知到期末考试答案章节答案2024年山东科技大学

材料力学智慧树知到期末考试答案+章节答案2024年山东科技大学

答案:(a)>(b)>(c);Theyieldingstressesfortwolow-carbonsteeltensilespecimenswithlengthof50mmand100mmareS1andS2,respectively,elongationsare5and10respectively，then（）

答案:S1S2，510.Thecross-sectionalareaofapistonisA=2000mm2,whenthecylinderisfired,thepistonrodissubjectedtothemaximumaxialloadof400kN;Wheninhaling,themaximumaxialpressureis200kNdeterminetheaveragestress,stressamplitudeandcyclecharacteristicsofthepistonrod（）

答案:m=50MPa,a150MPa,r2;

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答案:WhenthetorqueTonthecross-sectionofaroundshaftremainsunchangedandthediameterisreducedbyhalf,theratioofthemaximumshearstressonthecross-sectiontotheoriginalmaximumshearstressis（）times.

答案:8

答案:Thecross-sectionalareaofapistonisA=3000mm2,whenthecylinderisfired,thepistonrodissubjectedtothemaximumaxialloadof600kN;Wheninhaling,themaximumaxialloadis120kN,theaveragestress,stressamplitudeandcyclecharacteristicsofthepistonrodareasfollows（）

答案:m=80MPa,a120MPa,r5

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答案:6Fa/(4EA)Asshowninthefigure,astraightrodABwithaconstantcrosssection,itslengthis3a,young’smodulusisEandthecrosssectionalareaisA.LoadingconditiononrodABisasshowninthefigure,thentheverticaldisplacementofthemiddlesectionis:（）

答案:Fa/(EA);

答案:4(ab)P/(ad2);

答案:m2=8m1.Thetensilestress-straincurvesofa,bandcareshowninthefigurebelow.Material___withthemaximumtensilestrength,material______withthegreateststiffness,material________withthebestplasticity.（）

答案:a，c，c;

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答案:DisplacementofSectionDisPl/(2EA);Thefollowingfigureshowsdifferentstresselements(units:MPa),whichfiguregives1Dstressstate（）

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答案:Solidcircularshaft1andhollowcircularshaft2,theircross-sectionalareaisthesame,subjecttothesametorque,τmax1andτmax2arethemax