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1、Engineeringmechanics(II)(material)13springonlineassignment314,spring13,"engineeringmechanics(material)"13springonlineassignment3Examtime:100testtime:SingletopicselectionMultiplechoiceTrueorfalse(10questionsintotal,40points.)Theneutralaxisandtheexternalforceofthec
2、rosssectionoftheeccentricpullbarareattheoppositesideofthe().A.axisofsymmetrySectioncenterPrincipalinertiaaxisD.ThemaininertiaaxisFullmarks:4Thefollowingconclusionaboutthegeneralperformanceofmaterialmechanicsis().Thetensilestrengthofbrittlematerialislowerthanitsab
3、ilitytoresistpressureThetensilestrengthofbrittlematerialissuperiortoitsabilitytoresistpressureC.plasticmaterialsaremoreresilientthantheyareThetensilestrengthoftheD.PlasticmaterialissuperiortoitsshearingabilityFullmarks:4Themaximumpositivestressinthecrosssectionof
4、thebeamis().OntheneutralaxisOntheaxisofsymmetryC.OnthefaredgeoftheneutralaxisFullmarks:4Thethrustbearingofthespaceforceisbinding().A.twoB.threeC.fourD.sixFullmarks:4Inastaticsystem,therearethreeredundantconstraints,andthesystemisinanindefinitenumberoftimes().A.th
5、reetimes6B.1C.NotsureFullmarks:46.TwosamerootlengthanddensityofhangingrodcrosssectionalareaA1andA2,respectively,setN1,N2,sigma1,sigma2respectively,themaximumaxialforceandstressintwoshots,is().A.N1=N2,sigma1=sigma2N1doesnotequalN2,sigma1isequaltosigma2C.N1=N2,sigm
6、a1isnotsigma2D.N1doesnotequalN2,sigma1doesnotequalsigma2Fullmarks:4Eccentricstretchingrod,thestressstateofallpointsexceptneutralaxisincrosssectionis().A.one-wayB.twotoThreetoC.D.DependingonthesituationFullmarks:43mainstresssigma1=24MPa,sigma2=0MPa,sigma3=-36mpa,m
7、aterialpoissonratio?Isequalto0.25,whichisthesumofthestresssigmar2is()MPa.A.33B.24C.-36D.60Fullmarks:4TheAnglebetweenthetwomainplanesofaflatstressstateis().A.45degreesB.90degreesC.60degreesD.180degreesFullmarks:4Intheformulaofthebendingandpositivestressofthebeam,E
8、Idenotes()TorsionalstiffnessPressurestiffnessFlexuralrigidityD.Fullmarks:414,spring13,"engineeringmechanics(material)"13springonlineassignment3Nouploadhomework