土木工程专业英语 陈瑛 1.2. determinate and indeterminate structures新_第1页
土木工程专业英语 陈瑛 1.2. determinate and indeterminate structures新_第2页
土木工程专业英语 陈瑛 1.2. determinate and indeterminate structures新_第3页
土木工程专业英语 陈瑛 1.2. determinate and indeterminate structures新_第4页
土木工程专业英语 陈瑛 1.2. determinate and indeterminate structures新_第5页
已阅读5页,还剩47页未读 继续免费阅读

下载本文档

版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领

文档简介

在线教务辅导网HTTP/WWWSHANGFUWANGCOM更多课程配套课件资源请访问在线教务辅导网12DETERMINATEANDINDETERMINATESTRUCTURES静定和超静定结构2018/1/102STATICALLYDETERMINATESTRUCTURESNSTRUCTURESARESAIDTOBESTATICALLYDETERMINATEWHENTHEFORCESANDREACTIONSPRODUCEDBYAGIVENLOADINGCANBECALCULATEDUSINGONLYTHEEQUATIONSOFEQUILIBRIUMSTATICALLYDETERMINATESTRUCTURESTATICALLYDETERMINATESTRUCTURESNTHESIMPLYSUPPORTEDBEAMSHOWNINFIGURE13ISSTATICALLYDETERMINATEWECANSOLVEFORTHETHREEUNKNOWNREACTIONSUSINGTHEEQUATIONSOFEQUILIBRIUMANDTHENCALCULATETHEINTERNALFORCESSUCHASBENDINGMOMENT,SHEARFORCE,ANDAXIALFORCEATANYGIVENLOCATIONALONGTHELENGTHOFTHEBEAMSTATICALLYDETERMINATESTRUCTURESTATICALLYINDETERMINATESTRUCTURESNFOURUNKNOWNREACTIONSNTHREEINDEPENDENTEQUILIBRIUMEQUATIONS,STATICALLYINDETERMINATESTRUCTURESSTATICALLYINDETERMINATEBEAMSATICALLYINDETERMINATEFRAMESATICALLYINDETERMINATECOMPOSITESTRUCTURESFORCEMETHOD力法NTHEFORCEMETHODALSOCALLEDTHEFLEXIBILITYMETHODISUSEDTOCALCULATEINTERNALFORCESANDREACTIONSINSTATICALLYINDETERMINATESTRUCTURESDUETOLOADSANDIMPOSEDDEFORMATIONSFORCEMETHOD力法NTHESTEPSINTHEFORCEMETHOD1DETERMINETHEDEGREEOFSTATICALINDETERMINACYOFTHESTRUCTUREPARAMETERNWILLBEUSEDTODENOTETHEDEGREEOFINDETERMINACYN确定超静定次数FPFPFAXFAYMAX1静定结构AABBCCNTHESTEPSINTHEFORCEMETHOD2TRANSFORMTHESTRUCTUREINTOASTATICALLYDETERMINATESYSTEMBYRELEASINGANUMBEROFSTATICALCONSTRAINTSEQUALTOTHEDEGREEOFSTATICALINDETERMINACY,NFPFPFAXFAYMAX1基本体系AABBCCPRIMARYSYSTEMNTHESTEPSINTHEFORCEMETHODTHISISACCOMPLISHEDBYNRELEASINGEXTERNALSUPPORTCONDITIONSNCREATINGINTERNALHINGESTHESYSTEMTHUSFORMEDISCALLEDTHEPRIMARYSYSTEMNUMBERTHERELEASEDCONSTRAINTSFROM1TONPRIMARYSYSTEMQQQAABBCCLLX1X1B基本体系A一次超静定结构N3FORAGIVENRELEASEDCONSTRAINTJ,INTRODUCEANUNKNOWNREDUNDANTRI5DQNDENTFORCEXJCORRESPONDINGTOTHETYPEANDDIRECTIONOFTHERELEASEDCONSTRAINT多余未知力REDUNDANTFORCE基本体系沿多余未知力方向的位移应与原结构位移相同FPFPFAXFAYMAX1基本体系AABBCCQQQAABBCCLLX1X1X1N4APPLYTHEGIVENLOADINGORIMPOSEDDEFORMATIONTOTHEPRIMARYSYSTEMCALCULATEDISPLACEMENTSDUETOTHEGIVENLOADINGATEACHOFTHERELEASEDCONSTRAINTSINTHEPRIMARYSYSTEMTHESEDISPLACEMENTSARECALLED1P,2P,NP,FPAABBC1PX1ABX11D1111D11X1FPABCEIL/2L/2X1基本体系1B0N5FORAGIVENRELEASEDCONSTRAINTJ,APPLYAUNITLOADXJ1TOTHEPRIMARYSYSTEMCALCULATEDISPLACEMENTSDUETOXJ1ATEACHOFTHERELEASEDCONSTRAINTSINTHEPRIMARYSYSTEMTHESEDISPLACEMENTSARECALLED,ABX11D11FPABCEIL/2L/2X1基本体系1B0FPAABBC1PX111D11X1UNITLOAD单位力,N6SOLVEFORREDUNDANTFORCESX1THROUGHXNBYIMPOSINGTHECOMPATIBILITYCONDITIONSOFTHEORIGINALSTRUCTURETHESECONDITIONSTRANSFORMTHEPRIMARYSYSTEMBACKTOTHEORIGINALSTRUCTUREBYFINDINGTHECOMBINATIONOFREDUNDANTFORCESTHATMAKEDISPLACEMENTATEACHOFTHERELEASEDCONSTRAINTSEQUALTOZERONCALCULATEFORCESATAGIVENLOCATIONINTHESTRUCTUREUSINGNFORCECANBEBENDINGMOMENT,SHEAR,AXIALFORCE,ORREACTIONTHECLASSICALDISPLACEMENTMETHODNTHEFORCEMETHODUNKNOWNSAREFORCEQUANTITIESTHEREDUNDANTFORCESBASEDONGEOMETRICALCONDITIONSCOMPATIBILITYCONDITIONSATTHELOCATIONOFEACHREDUNDANTFORCENTHECLASSICALDISPLACEMENTMETHODUNKNOWNSAREDISPLACEMENTQUANTITIESBASEDONSTATICALCONDITIONSEQUILIBRIUMCONDITIONSZ1R211234134PR2P12234R22R12R11R1PZ2NTHESTEPSINTHECLASSICALDISPLACEMENTMETHOD1FORAGIVENSTRUCTUREANDLOADING,CONSIDERTHEJOINTSTOBEFULLYFIXEDAGAINSTROTATIONPL1234EI常数Z1Z2AB基本结构1234Z1Z2R100PR2NTHESTEPSINTHECLASSICALDISPLACEMENTMETHOD2CALCULATETHEMOMENTSINEACHMEMBEROFTHESTRUCTUREDUETOTHEGIVENLOADS,R1P,R2P,ASSUMINGFULLFIXITYATTHEJOINTSTHESEMOMENTSARECALLEDFIXEDENDMOMENTSN3CALCULATEMOMENTSR11、R12ATTHEENDSOFEACHMEMBERDUETOUNITDISPLACEMENTSOFTHEJOINTSN4EXPRESSTHETOTALMOMENTATEACHENDOFAGIVENMEMBERASTHESUMOFTHEFIXEDENDMOMENTSMP,ANDTHEPRODUCTOFUNKNOWNJOINTDISPLACEMENTSZ1,Z2TIMESTHEMOMENTSM1、M2PRODUCEDBYUNITJOINTDISPLACEMENTSZ1,Z2,CALCULATEDINSTEP3N5GENERATEANEQUATIONOFMOMENTEQUILIBRIUMATEACHJOINT基本结构在荷载等外因和结点位移的共同作用下,每一个附加联系中的附加反力矩或反力都应等于零静力平衡条件。N6SOLVETHESYSTEMOFEQUATIONSFORTHEUNKNOWNJOINTDISPLACEMENTSN7CALCULATETHEMEMBERENDMOMENTSUSINGTHEEXPRESSIONSDERIVEDINSTEP4ANDTHEVALUESOFJOINTDISPLACEMENTSCALCULATEDINSTEP6R11Z1R12Z2R1P0R21Z1R22Z2R2P0R11Z1R12Z2R1P0R21Z1R22Z2R2P0R1R11R12R1P0R2R21R22R2P0N8CALCULATEALLREMAININGFORCESINTHESTRUCTURESHEARFORCESANDAXIALFORCESNFORCEMETHODCANSOLVEALLSTATICALLYINDETERMINATESTRUCTURESCOMPUTATIONALCOMPLEXITYPROHIBITIVEFORSTRUCTURESWITHMORETHANTHREEUNKNOWNFORCESNCLASSICALDISPLACEMENTMETHODALLOWSASOLUTIONBASEDONAMEMBERBYMEMBERPROCEDURE,RATHERTHANONETHATREQUIRESCONSIDERATIONOFTHESTRUCTUREASAWHOLEBASEDONTHEPRESOLUTIONOFSTANDARDCASESOFINTERMEDIATE媒介物LOADANDDISPLACEMENTREDUCETHENUMBEROFUNKNOWNSINAGIVENSOLUTIONMOMENTDISTRIBUTIONMETHOD力矩分配法NTHEMOMENTDISTRIBUTIONMETHODISUSEDFORSTATICALLYINDETERMINATEBEAMSANDFRAMESBYSIMPLEHANDCALCULATIONSNTHISISBASICALLYANITERATIVE5ITERETIV迭代的PROCESSNTHEPROCEDUREINVOLVESARTIFICIALLYRESTRAININGTEMPORARILYALLTHEJOINTSAGAINSTROTATIONANDWRITINGDOWNTHEFIXEDENDMOMENTSFORALLTHEMEMBERSRESTRAINALLTHEJOINTSAGAINSTROTATIONWRITEDOWNTHEFIXEDENDMOMENTSNTHEJOINTSARETHENRELEASEDONEBYONEINSUCCESSIONSEK5SEFEN连续ATEACHRELEASEDJOINTTHEUNBALANCEDMOMENTSAREDISTRIBUTEDTOALLTHEENDSOFTHEMEMBERSMEETINGATTHATJOINTNACERTAINFRACTIONOFTHESEDISTRIBUTEDMOMENTSARECARRIEDOVERTOTHEFARENDSOFMEMBERSTHERELEASEDJOINTISAGAINRESTRAINEDTEMPORARILYBEFOREPROCEEDINGTOTHENEXTJOINTNTHESAMESETOFOPERATIONSARECARRIEDOUTATEACHJOINTTILLALLTHEJOINTSARECOMPLETEDTHISCOMPLETESONECYCLEOFOPERATIONSTHEPROCESSISREPEATEDANUMBEROFTIMESORCYCLESTILLTHEVALUESOBTAINEDAREWITHINTHEDESIREDACCURACYMEMBERDISTRIBUTIONFACTOR弯矩分配系数NGIVENAUNITMOMENTAPPLIEDTOJOINTA,WHATMOMENTSAREPRODUCEDINEACHOFTHEMEMBERSFORAUNITROTATIONTHEMOMENTINEACHMEMBERATJOINTAISJUSTITSSTIFFNESSJOINTSTIFFNESSMEMBERDISTRIBUTIONFACTORNDISTRIBUTIONFACTOROFMEMBERIATJOINTAMEMBERDISTRIBUTIONFACTORMEMBERSTIFFNESS/JOINTSTIFFNESSNTHECENTERJOINTISFIXEDTHEROTATIONISSETTOZEROWHICHGIVESTHESOCALLEDFIXEDENDMOMENTSOLUTIONFORBEAMONTHERIGHTANDNORESPONSEINTHEBEAMONTHELEFTTHIS

温馨提示

  • 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
  • 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
  • 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
  • 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
  • 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
  • 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
  • 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

评论

0/150

提交评论