简介：Thestiffenedcylindricalshelliscommonlyusedforthepressurehullofsubmersiblesandthelegsofoffshoreplatforms.Therearevariousfailuremodesbecauseofuncertaintywiththestructuralsizeandmaterialproperties,uncertaintyofthecalculationmodelandmachiningerrors.Correlationsamongfailuremodesmustbeconsideredwiththestructuralreliabilityofstiffenedcylindricalshells.However,thetraditionalmethodcannotconsiderthecorrelationseffectively.Theaimofthisstudyistopresentamethodofreliabilityanalysisforstiffenedcylindricalshellswhichconsidersthecorrelationsamongfailuremodes.Firstly,thejointfailureprobabilitycalculationformulaoftworelatedfailuremodesisderivedthroughuseofthe2Djointprobabilitydensityfunction.Secondly,thefullprobabilityformulaofthetandemstructuralsystemisgivenwithconsiderationtothecorrelationsamongfailuremodes.Atlast,theaccuracyofthesystemreliabilitycalculationisverifiedthroughuseoftheMonteCarlosimulation.Resultoftheanalysisshowsthefailureprobabilityofstiffenedcylindricalshellscanbegainedthroughaddingthefailureprobabilityofeachmode.

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简介：Theobjectiveofthisworkistoanalyzethefatiguereliabilityofcomplexweldedstructurescomposedofmultipleweb-framejoints,accountingforcorrelationeffects.Athree-dimensionalfiniteelementmodelusingthe20-nodesolidelementsisgenerated.Alinearelasticfiniteelementanalysiswasperformed,hotspotstressesinaweb-framejointwereanalyzedandfatiguedamagewasquantifiedemployingtheS-Napproach.Thestatisticaldescriptorsofthefatiguelifeofanon-correlatedweb-framejointcontainingseveralcriticalhotspotswereestimated.Thefatiguereliabilityofaweb-framejointwasmodeledasaseriessystemofcorrelatedcomponentsusingtheDitlevsenbounds.Thefatiguereliabilityoftheentireweldedstructurewithmultipleweb-framejoints,modeledasaparallelsystemofnon-correlatedweb-framejointswasalsocalculated.