第1題Thestrength,stiffnessandstabilityofthecomponentarerelatedtothemechanicalpropertiesofthematerialaswellastheshapeandsizeofit.

第1題Accordingtothetwo-forcebalanceprinciple,twoforcesshouldsatisfytheconditions,pointingoutthatoneofthefollowingstatementsiswrong.AIt'sactingonthesamerigidbodyBActionisequaltoreaction,butitactsinacontrarydirectionCAlongthesamelineDThetwoforcesareactionandreaction第2題Theprojectionofaforcealonganaxisandthecomponentofaforcealonganaxis().ABotharevectorsBBotharegenerationquantitiesCProjectionisthenumberofgenerations,andthecomponentforceisthevector.DProjectionisthevector,andthecomponentforceisthenumberofgenerations0.3Introduction3第1題Stiffnessreferstothecapacityofthememberto().AResistancemovement

BResistancetodestructionCResistancetodeteriorationDResistancetodeformation第2題Thethreeelementsthatdeterminetheeffectofaforceonanobjectdonotinclude().AThemagnitudeoftheforceBDirectionofforce

CUnitofforceDActionpointofforce第3題Themomentistheproductofthemagnitudeoftheforceand().AdistanceBlengthCArmofforceDCouplearm0.4Introduction4第1題Thecorrectnumberinthefourcellsshowninthefigureis

().(Theunitofstressinthefigureis

MPa)fontABCD1.1.1FundamentalKnowledgeonStatics第1題Therelationshipbetweenforceandobjectiscorrect().AForcescannotexistindependentlyofobjectsBIngeneral,theforcecannotexistindependentlyfromtheobjectCForcescanbedetachedfromobjects第2題Theelementsthatdeterminetheeffectofforceonanobjectare().AThemagnitudeoftheforceBDirectionofforceCActionpointofforceDTheabovethreeitems第3題Theapplicablescopeofforcebalanceconditionis()AdeformablebodyBtherigidbodysystemCrigidbodyDAnyobjectorsystemofthings1.1.2AxiomsinStatics第1題Inthetwo-forcebalanceaxiom,thereare()objectsinteractingwitheachother.A

OneBTwoCThreeDFour第2題Aslongasahorizontalforceisappliedtoanobjectplacedonahorizontalplane,theobjectwillnotstandstill.第3題Inthetwoforcebalanceaxiom,thereare()objectsinteractingwitheachother.A1B2C3D4第4題Thebalanceofanobjectreferstoitsstaterelativetotheearth().AKeepstillBMoveinastraightlineataconstantspeedCAlloftheabovearetrue第5題thetranslationoftheforcemustbeappliedtotheforceatapointontherigidbody().Aparalleltoanypoint

BarbitrarytoanypointCMovetoanypointalongthelineofactionoftheforceDMoveparalleltoanypointalongthelineofactionoftheforce第6題Intheforceparallelogramshownhere,thegraphofthecombined

forcesandis（

）.Afigure（a）Bfigure（b）Cfigure（c）Dfigure（d）1.1.3Momentofaforce第1題Theprojectionofthemomentofaforceonthepointontheaxismustbeequaltothemomentofforceonthataxis.第2題Coupleandmomentaredifferentconcepts.第3題Twocouplesinthesameplaneareequivalenttoeachotheraslongastheirmomentsareequal.第4題Twoforcesofequalsizemusthaveequalmomentsforanaxle.第5題IftheforceFintersectstheZaxis,thenMz(F)=0.第6題Theconditionthatthemomentisnotzerois().ATheforceisnotzeroBThelineofactionoftheforcedoesnotpassthroughthecenterofmomentCTheforceandarmarenotzero1.2.1Constraintandreactiveforce第1題Thebindingforceonthesmoothfaceoftheobiectactsatthecontactpointinadirectionalongthecommonnormalofthecontactsurface,and().APointattheforceobjectwithconstantforce

BPointatthestressedobject,constantpressureCDerivedfromtheforcebody,constantforceDDeviationfromthebearingbody,constantpressure第2題Thesupportwhichonlyallowsteobjecttomoveinanydiectionanddoesnotrestricttherotationoftheobjectiscalled().AfixedhingesupportBmovablehingesupportCfixedendsupportDSmoothsurface第3題Thecircumference()aroundwhichanobjectactsasarestraintiscalledarestraint.

AOtherForcesBOtherForceSystemsCOtherobjectsDOthermaterials第4題Asshowninthefigure,suspendtheweightfromtheceilingwitharopewhereFTisthetensionoftheropeagainsttheweight,FTˊ.Thetensionofaheavyobjectagainstarope,ofwhichtheactingandreactingforcesare().A

GandFTBFTandFTˊCGandFTˊD

None第5題Thetranslationtheoremofforceisonlyapplicabletoarigidbody,anditcanonlybeappliedtothesamerigidbody.第6題Foracertainobjecttoplayalimitingrolearound(),calledconstraints.AOtherforcesBOtherforcesystemsCOtherobjectsDOthermaterials第7題Thedirectionoftheconstraintisthesameasthedirectionofdisplacementthattheconstraintcanblock().AidenticalBcontraryCuncertainD

irrelevant1.2.2Forceanalysis第1題Therigidbodyisinequilibriumundertheactionofthreeforces,thentheactionlineofthethreeforces().AmustmeetatoneBmustbeparalleltoeachotherCwillallzerosDmustbeinthesameplane第2題Thethree-hingedrigidframeshowninthefigureissubjectedtohorizontalforceP.Therearefourstatementsasfollows,ofwhichthewrongoneis().AACisthetwo-forcebalancebarmemberBACisthetwo-forcebalancebarmemberCThedirectionofthereactionforceRAandRBpointstoCDThedirectionofRApointstoC,andthedirectionofRBisuncertain第3題Accordingtothediagram(excludingtheweightofthebar),theforcediagramofbarABiscorrect().ABCD第4題

Aforcecanonlymakearigidbodymove.第5題Forcecanmakearigidbodymoveandrotate.第6題Forceistheinteractionbetweenobjects,itseffectcanbedividedintoexternaleffectandinternaleffect.1.3.1Couples第1題Thestatementaboutthecoupleandthemomentofthecouple,where()iscorrect.AOnlytwoforceswithequalmagnitude,oppositedirectionsandparallellinesofactionarecalledcouplesBTheforcecoupleproducesbothrotationalandmovingeffectsontherigidbodyCAforcecouplecanbereducedtoaforceandthereforecanbeequivalenttoaforceDThemomentofthecoupleatanypointisequaltothemomentofthecouple1.4.1Reductionofgeneralcolplanarforcesystem第1題Asshowninthefigure,threepointsA,BandConaplanearerespectivelysubjectedtoforceP,ABCisanequilateraltriangle,thenthisforcesystem()AbalanceBbalanceCResultanttorqueis0DResultantforceis01.4.2Equilibriumofgeneralcoplanarforcesystem第1題Onenecessaryandsufficientconditionfortheequilibriumofplaneintercrossingforcesystemsisthattheresultantforceiszeroandtheforcepolygonclosesitself.第2題Theplaneconfluenceforcesystemcansolveatmost()unknowns.AOneBTwoCThreeDFour1.4.3Equilibriumofgeneralcoplanarforcesystem第1題Theintersectiontheoremofthreeforcesequilibriumisthe()conditionofcoplanarandnonparallelthreeforcesequilibrium.AsufficientBnecessaryCnecessaryandsufficient1.5.1Equilibriumofrigidbodysystems第1題Theforcecanonlymaketherigidbodymove,andthecouplecanonlymaketherigidbodyrotate.第2題Insolvingtheequilibriumproblem,thedirectionoftheunknownconstraintreactionforceintheforcediagramcanbearbitrarilyassumed.Ifthecalculationresultispositive,thentheassumeddirectionistheactualdirectionoftheforce.第3題Theresultantforce(ifanyresultantforceexists)ofanyforcesysteminspacemustbeequaltotheprincipalvectorobtainedwhentheforcesystemissimplifiedtoanyotherdirection.第4題Theforceisdecomposedalongthespatialcoordinateaxisandtheresultshouldberegardedasanalgebraicquantity.第5題TheprojectionofaspaceforceGontheX-axisandthemomenttakenontheX-axishavethefollowingresults,namelyFx=0,Mx(F)=0,fromwhichitisknownthattheforceisperpendiculartotheX-axisandislocatedontheplanepassingthroughtheX-axis.第6題Thenecessaryandsufficientconditionforbalanceofspaceintersectionforcesystemisthattheresultantforceofforcesystemiszero.第7題Sincethereareonlythreeuniqueequationsforthesystemofintersectionforcesinspace,theproblemofbalanceofthissystemofforcesinspacecanonlybesolvedbythreeunknownquantities.第8題Foragivenarbitraryforcesystem,thepositionoftheprincipalvectorandthesimplifiedcenterisdetermined().ARelevantBirrelevantCuncertain1.6.1Slidingfriction第1題Whenapersonwalks,thedirectionoffrictionbetweenthegroundandthesoleis().AforwardBbackwardCUp第2題TheweightofobjectAisQ,placedonthehorizontalsurface,thestaticslidingfrictioncoefficientf=0.32onthecontactsurface,andwhenahorizontaltensionP=0.3Qisappliedtotheobject,thefrictionFonthecontactsurfaceis().AF=0BF=0.3QCF=0.32QDF=Q第3題Generally,themaximumstaticfrictionishigherthanthedynamicslidingfriction

().ASmallBlarge

CequallyDTwiceasbig1.6.2Equilibriumproblemswithfriction第1題Asshowninthefigure,theweight100NispressedagainsttheverticalwallwithaforceofF=500N,andthefrictioncoefficientf=0.3betweentheobjectandthewallis().

A100NB150NC0Duncertain第2題Whenthebodyisincriticalequilibrium,themagnitudeofstaticfriction().AItisproportionaltothemassoftheobjectBItisproportionaltothegravityoftheobjectinthenormaldirectionofthesupportingsurfaceCItisdirectlyproportionaltothepositivepressurebetweenobjectsincontactDItisdeterminedbytheequilibriumequationoftheforcesystem第3題Themaximumstaticfrictionisproportionaltothevalueof().APositivepressureBgravityCAcomponentofgravity第4題Thewaytoincreasefrictionis().AReducefrictioncoefficientBIncreasefrictioncoefficientCIncreasecontactareaDReducepositivepressure1.6.3Truss第1題Thelineofactionofthetwoforcesactingonthetwobarmustbealongthelineofthetwoactingpoints.1.6.4Spacegeneralforcesystem第1題Iftheforcevectorsaredrawnindifferentorder,theshapeofthefinalforcepolygonwillbedifferent.2.7.1Introduction2第1題Ofthefollowingconclusions,only()istrue.AThetaskofmaterialmechanicsistostudythecompositionofmaterialsBThetaskofmaterialmechanicsistostudythemechanicalpropertiesofvariousmaterialsCThetaskofmechanicsofmaterialsistoprovidethebasictheoryandmethodofanalysisandcalculationfordesigningthestructureofcomponentsundertheprincipleofbothsafetyandeconomyDThetaskofmaterialmechanicsistodesignthestructureofthecomponentundertheprincipleofensuringsafety2.7.2Introduction3第1題Thesafetyfactorofplasticmaterialingeneralmachinerymanufactureatpresent（

）safetyfactorofgeneralbrittlematerials.AlessthanBgreaterthanCequaltoDcannotcompare2.7.3Introduction1第1題

()aretwobasicphysicalquantitiesinmechanicsATorqueandCoupleTorqueB

ForceandcoupleCMassandweightDForcesandtorques2.7.4Introduction4第1題Withregardtothegeneralmechanicalpropertiesofmaterials,pleasedecidewhichoneiscorrect().AThetensilestrengthofAbrittlematerialislowerthanitscompressivestrengthBThetensilestrengthofabrittlematerialishigherthanitscompressivestrengthCThetensilestrengthofaplasticmaterialishigherthanitscompressivestrengthDThetensilestrengthofabrittlematerialisequaltoitscompressivestrength2.8.1Internalforcesofaxiallyloadedmembers第1題Thesectionmethodisgenerallyapplicabletouniformandvariablesectionbars(straightandcurved),elasticandplasticdeformation,basicdeformationandcombineddeformation.2.8.2Internalforcesofaxiallyloadedmembers第1題Thereisonlynormalstressandnoshearstressinthememberunderaxialtension(compression).第2題Whenthelowcarbonsteelspecimensyieldintension,asliplineabout45°directionwiththeaxisappearsonthesurface,whichisrelatedtothemaximumshearstress2.8.3Deformationofarodintensionorcompression第1題Thetwoendsofastraightbarareactedonbyapairofforcesequalinvalueandoppositeinthelongitudinalplaneofsymmetry,andthestraightbarwillproduce(

).AtensionandcompressiondeformationBsheardeformationCbendingdeflectionDtorsionaldeformation2.8.4Mechanicalpropertiesofmaterials（1）第1題Forbrittlematerial,plasticyieldfailurewillnotoccur.

第2題Ifthestressinacertaindirectioniszero,thestraininthatdirectionmustbezero.2.8.5Mechanicalpropertiesofmaterials（2）第1題Theultimatestressasabrittlematerialis().AElasticlimitBYieldlimitCStrengthlimitDProportionalLimit

第2題Theelongationoftheplasticmaterialshall().A<5%B=5%

CThereisnofixedstandardD>5%2.9.1TorsionExternalcouplemoment，internaltorqueandinternaltorquediagram第1題Thehigherthespeedoftheshaft,thegreaterthetorqueonthecrosssectionoftheshaft.

2.9.2TorsionCirculartubeintorsion第1題Whenthecircularaxisistorsional,theshearstressonthesamecircumference().AExactlythesameBcompletelydifferentCpartsofthesameDUnabletodetermine2.9.3TorsionStressofCircularShaft（I）第1題Whenonecircularaxisistwisting,therearebothnormalstressandshearstressonthecrosssection.第2題Whentheconstantsectionstraightbaristwisted,thecrosssectionofthebarremainsflatafterdeformation,anditsshapeandsizeremainunchanged.第3題Theresultsshowthatthecastironroundbarwillfractureatthemaximumtensilestresssurfacewhenitisundertorsionandaxialtension第4題Thecrosssectionandthelongitudinalsectionofacircularrodremainplanewhenitistwisted2.9.4TorsionStressofCircularShaft（II）第1題Ifthediameterofthesecondshaftistwicethatofthefirstshaftunderthesametorqueactionoftwocircularshaftsofthesamelength,thentheratioofthemaximumshearstressbetweenthefirstshaftandthesecondshaftis().A2:1B4:1C8:1D16:12.9.5StrengthenConditionofCircularShaftinTorsion第1題Theinnerandouterdiametresofthehollowcircularaxisaredandd,andtheratiooftheinnerandouterdiametresisd/D=α.Thecorrectexpressionsforthepolarmomentofinertiaandthetorsionalsectioncoefficientofthecrosssectionshouldbe（）AIp=πD4/64(1-α4),WP=πD3/32(1-α3)BIp=πD4/32(1-α4),WP=πD3/16(1-α3)CIp=π/32（D4-α4）,WP=π/16(D3-α3)DIp=πD4/32(1-α4),WP=πD3/16(1-α4)2.9.6DeformationandStiffnessConditionofCircularShaft第1題Castironroundrodswillfractureatthesurfaceofmaximumtensilestressinbothtorsionandaxialtension.2.10.1Shearstressandstrain第1題WhentheshearforceofasectionFQ=0().AThereisAsuddenchangeinbendingmomentonthissectionBThebendingmomentonthissectionhasanextremevalueCThebendingmomentonthissectionmustbethemaximumofthebeamD

Thebendingmomentonthissectionmustbezero2.10.2Practicalcalculationofbearing第1題Thecompressionstrengthoftheboltcanbeimprovedbyplacingawasherbetweentheplateandthetensionboltasshowninthefigure.第2題Thehingeconnectionoftwopartswithcylindricalpincannotonlylimittherelativemovementoftwoparts,butalsolimittherelativetransmissionoftwoparts.2.11.1Bendingbeamintroduction1第1題Thebasicformsofstationarybeamsare().ASimplesupportedbeam

BExtendingbeamCcantileverbeamDTheabovethreeitems第2題Inplanebending,theexternalforces(orcouples)actingonthebeam().AOnaxis

B

LongitudinalsymmetryinplaneCInsideShaftFace

2.11.2Internalforcesofbeamshearforceandbendingmoment第1題Forbeam’sdeformation,theangleofrotationisthelargestwherethebendingmomentisthelargest,andtheangleofrotationisalsozerowherethebendingmomentiszero.

2.11.3ForceandBendingMomentEquationsShearforceandbendingmomentDiagram第1題Theinternalforcesoftherodsinastaticallyindeterminatestructuredonotcausedeformation.2.11.4ShearForceandBendingMomentEquationsShearforceandbendingmomentDiagram4第1題Theultimatestressofplasticmaterialsisgenerally（）.AyieldlimitBultimatestrengthCproportionallimit

Delasticlimit2.11.5Relationsamongloadshearforceandbendingmoment第1題Forbeam’sdeformation,apositivemomentwillproduceapositiveangleofrotationandanegativemomentwillproduceanegativeangleofrotation.

第2題Thecrosssectionwiththelargestbendingmomentonthebeamhasthelargestdeflection,andwherethebendingmomentiszero,theangleofrotationiszero.第3題Themaximumbendingmomentmustoccuratthecrosssectionwithzeroshearforce.2.12.1PropertiesofPlaneArea-1第1題Themomentofforcecoupleism,andthediameterisDaccordingtothestrengthcondition.Whentheexternalforcecouplemomentincreasesto2m,thediametershouldincreaseto()A1.89B1.26C1.414D22.12.2Propertiesofplanearea-2第1題Forhollowandsolidcircularshaftswiththesamematerialandcross-sectionalarea,thetorsionalstiffnessoftheformermustbethesameasthatofthelatter.AlessthanBequaltoCgreaterthanDcan'tcompare2.13.1Stressofpurebending-1第1題

Incaseofpurebendingofthebeam,theinternalforceonthesectionis()Abendingmoment

BtorqueCshearforceDAxialforceEshearingforceandbendingmoment第2題Whenaplaneisbending,theneutralaxisisperpendiculartotheloadingsurface.第3題Forpurebending,theaxisofthebeamafterdeformationisacirculararc.第4題Inplanebending,theneutralaxisisperpendiculartotheloadingsurface.2.13.2Normalstressofpurebending-2第1題ForcastironbeamswithTsection,themaximumtensilestressalwaysoccursatthecrosssectionwiththemaximumpositivebendingmoment.

2.13.3Normalstressofbeaminpurebending第1題Forpurebending,hecrosssectionremainsflatafterdeformation,anditsshapeandsizewillnotchange.

第2題Accordingtotheequation,thebendingmomentMisaconstantiftheshearstress

ofonebeam’scrosssectionmeets.

2.13.4Shearstressinbending4第1題IfonlyoneconcentratedforceF

isappliedonthesimplebeam,thenthemaximumshearstressofthebeamsatisfies

andthemaximumbendingmomentofthatbeamsatisfies

wherel

beingthelengthofthebeam.

2.13.5StrengthProblemsofBeam5第1題Theouterdiameterofahollowsteelshaftandasolidaluminumshaftisthesame.Bycomparingthetorsionalsectioncoefficientofthetwo,wecanknow（

）AhollowsteelshaftislargerBthesolidaluminumshaftislargerCit'sthesamevalueDitsmagnitudeisrelatedtotheshearmodulusoftheshaft3.14.1Basicconceptsofbendingdeformation第1題Whenabeamisbentinaplane,itscrosssectionrotatesabout().AAxisofbeamBThelongitudinalaxisofsymmetryinacrosssectionCLineofintersectionbetweentheneutrallayerandthelongitudinalplaneofsymmetryDtheneutralaxis3.14.2Approximatedifferentialequationofdeflectioncurve第1題Themaximumnormalstressinbendingofthebeamis().ANeutralshaft

BOntheaxisofsymmetryCOntheedgefurthestfromtheneutralaxis3.14.3Calculationofbeamdeformationbyintegralmethod第1題Whentheloadonthebeamisonlyconcentrated,thebendingmomentisshownas().AHorizontalLineBCurveCObliqueLine3.14.4Calculationofbendingdeformationbysuperpositionmethod第1題Whenabeamissubjectedtoseveralforcesatthesametime,thedeflectionandangleofrotationofonecrosssectionareequaltothealgebraicsumofthedeflectionandangleofrotationofthatcrosssectionundereachforce.

3.14.5Stiffnessofabeam第1題Inthefollowingfourcases,()iscalledpurebending.ATheloadisactedonthelongitudinalsymmetryplaneofthebeamBOnlybendingoccursinthebeam,withouttorsionandtensiondeformationCWhentheplaneisbent,thereisonlybendingmomentbutnoshearforceoneachsectionofthebeamDWhentheplaneisbent,therearebendingmomentsandshearingforcesoneachsectionofthebeam3.14.6StaticallyIndeterminateBeams第1題Tosolvethestaticallyindeterminatestructure,itisnecessarytoestablishthedeformationcoordinationequation,thatis,thegeometricrelationshipbetweenthedeformationsofeachbar.

3.15.1Abriefintroductiontothestressstate1第1題IntheInternationalSystemofUnits,thebasicunitofstressis().

APa［帕］Bkg［千克］

CkN［千牛］DN［牛頓］第2題Thereisnoyieldorneckingphenomenoninbrittlematerialspecimensduringtension.第3題Thesuperpositionofonetwo-dimensionalstressstateandanothertwo-dimensionalstressstateresultsintwo-dimensionalstressstate.3.15.2Descriptionofthestressstateatonepoint2第1題

Onebidirectionalstressstateissuperimposedonanotherbidirectionalstressstate,andtheresultisstillabidirectionalstressstate.

3.15.3Stressanalysisinanarbitraryinclinedcrosssection3第1題Thetaskofstudyingthestateofstressatapointis().AUnderstandthestressvariationatdifferentsectionsBUnderstandthechangeofstressonasectionwithexternalforceCThetensilestrengthofaplasticmaterialishigherthanitscompressivestrengthDFindoutthestresschangeruleofapointatdifferentazimuthsection3.15.4Principalstress,principalsurfaceandmaximumshearingstress4第1題Theactingsurfaceofthemaximumorminimumnormalstressmustbethemainplane.第2題Intheelement,theremustbenonormalstressintheplanewherethemaximumshearstressresides.第3題Theactionsurfaceofthemaximumorminimumnormalstressmustbetheprincipalplane第4題Intheelementbody,theremustbenonormalstressintheplaneofthemaximumshearstress3.15.5Mainreasonsforthecollapseofmaterials5第1題Whenthetensilelowcarbonsteelspecimenyields,asliplineappearsonitssurfaceinthedirectionofabout45°withtheaxis,whichisrelatedtothemaximumshearstress.3.15.6Analysisoftheplanarstressstate-graphicmethod第1題Regardingthestress,()iscorrectinthefollowingconclusion.AStressisdividedintonormalstressandshearstress.BStressistheaveragevalueofinternalforces.C

Thenormalstressateachpointonthesamesectionisthesame.D

Thedirectionofshearstressateachpointonthesamesectionisthesame.3.15.7Stress-strainrelationinthecomplexstressstate第1題Ifthestressofthebarinacertaindirectioniszero,thenthestraininthatdirectionmustalsobezero.

第2題Theaxialforce,cross-sectionalareaandlengthofthetworodsareallthesame,butthematerialisdifferent,sothestressonthecross-sectionofthetworodsisthesameandthestrainisdifferent.第3題Thenormalstressesonthetwomutuallyperpendicularsectionsofthetwo-directionstressstateelementbodyhavethesamemagnitudeandoppositesign.

3.15.8Criterionofstrength第1題Accordingtothesecondstrengththeory,cast-ironcomponentsaresaferinbiaxialstretchthaninuniaxialstretch.3.15.9Applicationexamplesofthetheoryofstrength第1題

Nomatterwhichstateofstressaplasticmaterialisin,thethirdorfourththeoryofstrengthshouldbeappliedinsteadofthefirstorsecondtheoryofstrength.第2題Theresultsshowthatthefractureofcastironisalongthecrosssectionduringtensiletest().ATorsionfailure

BTensilefailure

CShearfailure

DCrushingfailure第3題Theresultsshowthatthelowcarbonsteelspecimensfracturealongthecrosssectionintorsion().ATorsionfailure

BTensilefailure

CShearfailureDCrushingfailure第4題Whenthecastironspecimenistwisted,thespiralsurfacewith45°angletotheaxiswillfracture().ATorsionfailure

BTensilefailure

CShearfailure

DCrushingfailure第5題Thereasonforfailureoflowcarbonsteelspecimeninuniaxialtensiletestisthat().ATorsionfailure

BTensilefailureCShearfailureDCrushingfailure第6題Thereasonforthefailureofcastironspecimeninuniaxialcompressiontestisthat().ATorsionfailure

BTensilefailure

CShearfailureDCrushingfailure第7題Thesumofthenormalstressesonthetwomutuallyperpendicularsectionsoftheelementbodyinthetwo-dimensionalstressstateisconstant第8題Theequivalentandinversesignofshearstressontwomutuallyperpendicularsectionsofelementbodyintwo-dimensionalstressstate.第9題Thefailureofplasticmaterialmustbecausedbyplasticyielding第10題Thethreeprincipalstressesontheelementare50MPa,0and-50MParespectively.Thevalueoftheequivalentstressofthethirdstrengththeoryis().A100MPaB0MPa

C50MPaD-50MPa第11題Thethreeprincipalstressesontheelementbodyare60MPa,10MPaand-50MParespectively,andthemaximumshearstressoftheelementis().A55MPa

B0MPaC60MPaD50MPa

3.16.1Compositedeformation1第1題Thereisnormalstressbutnoshearstressintheaxialtension(compression)specimen.3.16.2Compositedeformation2第1題Thesectionmethodisgenerallyapplicabletobarswithconstantandvariablesections(straightandcurved),elasticandplasticdeformation,basicdeformationandcombineddeformation第2題Eccentricstretchingisacombineddeformationofstretchingandbending.第3題Thecircularcross-sectionrod()isobliquelybent.Aimpossible

BcertainCuncertain

第4題Theforcecharacteristicofobliquebendingdeformationisthattheactinglineofexternalforcepassesthroughthecentroidofthesection,butdoesnotcoincidewiththeaxisofsymmetryofthesection.3.16.3Compositedeformation3第1題Forconstantsectionbeam,themaximumnormalstress

mustappearatthecrosssectionwhichhasthem