用OpenSees進(jìn)行截面彎矩

用OpenSees進(jìn)行截面彎矩-曲率分析,分析結(jié)果可用于SAP2000自定義鉸屬性MomentCurvatureExampleFromOpenSeesWikiThisnextexamplecoversthemoment-curvatureanalysisofarectangularreinforcedconcretesection.InthisexampleaZeroLengthelementwiththefiberdiscretizationofthecrosssectionisused.Inadditiontoprovidingunderstandingastothecreationofafibersection,theexampleintroducesTcllanguagefeaturessuchasvariableandcommandsubstitution,expressionevaluationandtheuseofprocedures.Hereisthefile:MomentCurvature.tclNOTE:Thelinesinthedashedboxesarelinesthatappearintheinputfile.alllinesthatbeginwith#arecomments,theyareignoredbytheprogram(interpreter)butareusefulfordocumentingthecode.Whencreatingyourowninputscriptsyouarehighlyencouragedtousecomments.TclBasicsInthetclscriptthatistobepresented,variables,expressionsandproceduresareused.Avariableisasymbolicnamegiventosomeknownorunknownquantityorinformation,forthepurposeofallowingthenametobeusedindependentlyoftheinformationitrepresents.InTclavariableonceset(withthesetcommand)canthenbesubsequentlyusingthesyntaxof$variable.Thefollowingtclexamplesetsthevariablevtobe2.0,andthenprintstothescreenamessagesayingwhatthevalueofvis.setv3.0puts"vequals$v"Expressionscanbeevaluatedusingtheexprcommand.Whenusingtheexprcommand,mostmathematicalfunctionsfoundinanyprogramminglanguagecanbeused,e.g.sin(),cos(),max(),min(),abs(),...Itisalsotypicaltocombineanexpressioncommand,withasetcommand.Todothis,theexprcommandisenclosedinsquarebrackets[]'s.Thefollowingexampledemonstratesthesettingofavariablevtobe3.0,thesettingofanothervariablesumtobetheresultofaddingwhateverthevalueofthevariablevisto2.0,andfinallytheprintingtothescreenofamessagesayingwhatthecurrentvalueofsumis.Typically,theresultofanexpressionisthensettoanothervariable.Asimpleexampletoadd2.0toaparameterandprinttheresultisshownbelow:setv3.0setsum[expr$v+2.0]puts"sumequals$sum";#printthesumMomentCurvature.tclScriptThefilecontains2parts.ThefirstpartcontainsaprocedurenamedMomentCurvature,andthesecondpartcontainsthecreationofthesectionandthesubsequentcallingoftheprocedure.NOTES:1.TypicallyusefulproceduressuchasMomentCurvaturewouldbeplacedinaseparatefile.Thisisdonesothatotherscripts

canalsousethem.Itisonlyplacedinthesamefileheretolimitthenumberofdownloadsforthereaderofthisarticle.2.Inthereferencedfile,theprocedureproceedsthecallingoftheprocedure.Itmustalwaysbethus.Inthisarticlewediscussthesectiongenerationfirst.SectionDefinitionForthezerolengthelement,asectiondiscretizedbyconcreteandsteeliscreatedtorepresentthebehaviour.UniaxialMaterialobjectsarecreatedwhichdefinethefiberstress-strainrelationship's.Thereisconfinedconcreteinthecore,unconfinedconcreteinthecoverregion,andreinforcingsteel.thefigure.Thesectionthereis1.5inchcoverz-axis.ThesectionisThedimensionofthesectionareasshownindepthis24inches,thewidth15inches,andallaround.Strongaxisbendingisabouttheseparatedintoconfinedandunconfinedconcreteregions,forwhichseparatediscretizationswillbegenerated,Reinforcingsteelisplacedaroundtheboundaryofththefigure.Thesectionthereis1.5inchcoverz-axis.Thesectionisfilewhichare"sourced""bythemainscript.Thefollowingarethecommandsthatgeneratethesectionandperformthemomentcurvatureanalysis.ThemodelandanalysiscommandsarecontainedintheMomentCurvatureprocedure.Thesearecontainedinaseperate#units:kip,in#Removewipeexistingmodel#CreateModelBuilder(withtwo-dimensionsand3DOF/node)modelBasicBuilder-ndm2-ndf3DefinematerialsfornonlinearcolumnsCONCRETEtagf,cec0f,cuecuCoreconcrete(confined)uniaxialMaterialConcrete011-6.0-0.004-5.0-0.014Coverconcrete(unconfined)uniaxialMaterialConcrete012-5.0-0.0020.0-0.006STEELReinforcingsteelsetfy60.0;#YieldstresssetE30000.0;#Young'smodulustagfyE0buniaxialMaterialSteel013$fy$E0.01setsomeparamaterssetcolWidth15setcolDepth24setcover1.5setAs0.60;#areaofno.7barssomevariablesderivedfromtheparameterssety1[expr$colDepth/2.0]setz1[expr$colWidth/2.0]Definecross-sectionfornonlinearcolumnssectionFiber1(filewhichare"sourced""bythemainscript.#units:kip,in#RemovewipeexistingmodelCreatetheconcretecorefiberspatchrect1101[expr$cover-$y1][expr$cover-$z1][expr$y1-$cover][expr$z1-$cover]Createtheconcretecoverfibers(top,bottom,left,right)patchrect2101[expr-$y1][expr$z1-$cover]$y1$z1patchrect2101[expr-$y1][expr-$z1]$y1[expr$cover-$z1]patchrect221[expr-$y1][expr$cover-$z1][expr$cover-$y1][expr$z1-$cover]patchrect221[expr$y1-$cover][expr$cover-$z1]$y1[expr$z1-$cover]Createthereinforcingfibers(left,middle,right)layerstraight33$As[expr$y1-$cover][expr$z1-$cover][expr$y1-$cover][expr$cover-$z1]layerstraight32$As0.0[expr$z1-$cover]0.0[expr$cover-$z1]layerstraight33$As[expr$cover-$y1][expr$z1-$cover][expr$cover-$y1][expr$cover-$z1]}Estimateyieldcurvature(Assumingnoaxialloadandonlytopandbottomsteel)setd[expr$colDepth-$cover];#d--fromcovertorebarsetepsy[expr$fy/$E];#steelyieldstrainsetKy[expr$epsy/(0.7*$d)]#Printestimatetostandardoutputputs"Estimatedyieldcurvature:$KySetaxialloadsetP-180setmu15;#TargetductilityforanalysissetnumIncr100;#NumberofanalysisincrementsCallthesectionanalysisprocedureMomentCurvature1$P[expr$Ky*$mu]$numIncrMomentCurvatureProcedureTheTclproceduretoperformthemoment-curvatureanalysisfollows.Theproceduretakesasinputthetagofthesectiontobeanalyzed,theaxialload,P,tobeapplied,themaxcurvaturetobeevaluatedandthenumberofiterationstoachievethismaxcuravature.Theprocedurefirstcreatesthemodelwhichconsistsoftwonodes,boundaryconditions,andaZeroLengthSectionelement.Adepictionofthegeometryisasshowninthetopmostfigureabove.Theimageontheleftshowsanedgeviewoftheelement,withlocalz-axiscomingoutofthepage.Node1iscompletelyrestrained,withtheappliedloadsactingatNode2.Anaxialload,P,isappliedtothesectionduringthemomentcurvatureanalysis.Afterthemodelhasbeencreated,theanalysisisperformed.Asingleloadstepisfirstperformedfortheaxialload,thentheintegratorischangedtoDisplacementControltoimposenodaldisplacements,whichmapdirectlytosectiondeformations.Areferencemomentof1.0isdefinedinaLineartimeseries.Forthisreferencemoment,theDisplacementControlintegratorwilldeterminetheloadfactorneededtoapplytheimposeddisplacement.Anoderecorderisdefinedtotrackthemomentcurvatureresults.Theloadfactoristhemoment,cMomentCurvature(secTagaxialLoadmaxK(numIncr100}}(#Definetwonodesat(0,0)node10.00.0node20.00.0Fixalldegreesoffreedomexceptaxialandbendingfix1111fix2010DefineelementtagndIndJsecTagelementzeroLengthSection112$secTagCreaterecorderrecorderNode-filesection$secTag.out-time-node2-dof3dispDefineconstantaxialloadpatternPlain1"Constant"(load2$axialLoad0.00.0}DefineanalysisparametersintegratorLoadControl0.0systemSparseGeneral-piv;#Overkill,butmayneedthepivoting!testNormUnbalance1.0e-910numbererPlainconstraintsPlainalgorithmNewtonanalysisStaticDooneanalysisforconstantaxialloadanalyze1DefinereferencemomentpatternPlain2"Linear"(load20.00.01.0}ComputecurvatureincrementsetdK[expr$maxK/$numIncr]Usedisplacementcontrolatnode2forsectionanalysisintegratorDispla