简介:Themostcriticalissueinthesteelcatenaryriserdesignistoevaluatethefatiguedamageinthetouchdownzoneaccurately.Appropriatemodelingoftheriser-soilresistanceinthetouchdownzonecanleadtosignificantcostreductionbyoptimizingdesign.Thispaperpresentsaplasticitymodelthatcanbeappliedtonumericallysimulateriser-soilinteractionandevaluatedynamicresponsesandthefatiguedamageofasteelcatenaryriserinthetouchdownzone.Utilizingthemodel,numerousriser-soilelementsareattachedtothesteelcatenaryriserfiniteelements,inwhicheachsimulateslocalfoundationrestraintalongtherisertouchdownzone.Theriser-soilinteractionplasticitymodelaccountsforthebehaviorwithinanallowablecombinedloadingsurface.Themodelwillberepresentedinthispaper,allowingsimplenumericalimplementation.Moreimportantly,itcanbeincorporatedwithinthestructuralanalysisofasteelcatenaryriserwiththefiniteelementmethod.Theapplicabilityofthemodelisinterpretedtheoreticallyandtheresultsareshownthroughapplicationtoanoffshore8.625″steelcatenaryriserexample.Thefatigueanalysisresultsofthelinerelasticriser-soilmodelarealsoshown.Accordingtothecomparisonresultsofthetwomodels,thefatiguelifeanalysisresultsoftheplasticityframeworkarereasonableandthehorizontaleffectsoftheriser-soilinteractioncanbeincluded.
简介:Theobjectiveofthisworkistoanalysefatiguereliabilityofdeckstructuressubjectedtocorrelatedcrackgrowth.Thestressintensityfactorsofthecorrelatedcracksareobtainedbyfiniteelementanalysisandbasedonwhichthegeometrycorrectionfunctionsarederived.TheMonteCarlosimulationsareappliedtopredictthestatisticaldescriptorsofcorrelatedcracksbasedontheParis-Erdoganequation.Aprobabilisticmodelofcrackgrowthasafunctionoftimeisusedtoanalysethefatiguereliabilityofdeckstructuresaccountingforthecrackpropagationcorrelation.Adeckstructureismodelledasaseriessystemofstiffenedpanels,whereastiffenedpanelisregardedasaparallelsystemcomposedofplatesandarelongitudinal.Ithasbeenproventhatthemethoddevelopedherecanbeconvenientlyappliedtoperformthefatiguereliabilityassessmentofstructuressubjectedtocorrelatedcrackgrowth.
简介:AmethodofreliabilityanalysisbasedonadirectstrengthcalculationemployingthevonMisesstressfailurecriterionispresentedhere.Theshorttermstraindistributionsofshiphullstructuralcomponentsareidentifiedthroughthestatisticalanalysisofthewave-inducedstrainhistoryandthelongtermdistributionsbytheweightedsummationoftheshorttermstraindistributions.Thewave-inducedlongtermstraindistributioniscombinedwiththestillwaterstrain.Theextremestraindistributionoftheresponsestrainisobtainedbystatisticalanalysisofthecombinedstrains.ThelimitstatefunctionofthereliabilityanalysisisbasedonthevonMisesstressfailurecriterion,includingtherelateduncertaintiesduetothequalityofthematerialandmodeluncertainty.ThereliabilityindexiscalculatedusingFORMandsensitivityanalysisofeachvariablethathaseffectsonthereliabilityisalsodiscussed.
简介:文章阐明了PBL教学法在“船舶强度与结构设计”课程教学中的应用,介绍了其具体实施步骤。实施效果显示,该方法取得了良好的教学效果,具有一定的参考意义。