Excessiveexternalpressuremayleadtocollapseofthepipe.Collapseusuallyinvolvesflatteningofthepipewhichimpedestheflowthroughit.However,thisisnotconsideredtobeacriticalfailuremodesincethedesigndepthisusuallywelldefined.Thisisalsoreflectedindesignrecommendation...[继续阅读]

    Offshorepipelinesareusedforoilandgastransportworld-wide.Dependingonapplication,pipelinescanbeclassifiedinto:(1)Exportpipelines,largediameterlinesforexportingprocessedoilandgasfromtheoffshoreinstallationtotheonshoreprocessingplantortothemarket;(2)Flowlines...[继续阅读]

    The4kmlongflowlineisexposedto100℃temperaturedifferenceatthehotend.Thenon-dimensionaltemperatureprofilesatdifferentinstantsintimeareshowninFigure10.8.OtherinputdataaresummarizedinTable10.3.Table10.3Inputparameters-simulationofflowlinewalkingParameterValueU...[继续阅读]

    FortheS-laymethodthepipestringisinstalledinanS-shapewherethepipeislaunchedhorizontallyfromthevessel,seeFigure7.1.Thisrequiresthatthepipeissupportedbyastingerthatprovidesasmoothtransitionfromthehorizontalpositiontoacertainangletermedthedepartureanglefromwh...[继续阅读]

    Inupheavalbucklinganalysis,themaintaskistoensurethatthesoilcoverprovidessufficientresistancetobalancetheupliftdrivingforceswithnecessarysafetymargintocaptureinherentuncertainties.Aprocedurefordocumentingthisduringpipelinedesigncanbefoundin(DNV,2007).Here,...[继续阅读]

    ByconsideringtheinfinitesimalelementinFigure8.3,assumingsmallanglesθ,andconsideringmomentequilibriumabouttheleftend:Furtherbyconsideringequilibriuminzdirection:Figure8.3InfinitesimalpipeelementByintroducingthatM=-EI(d2w)/(dx2),whereEIisthebendingstiffness...[继续阅读]

    Theunderstandingofpipeperformancecharacteristicsandrelatedfailuremodesisimportantforobtainingareliabledesignofflexiblepipesystems.Theexperiencegainedfromflexiblepipeapplicationsoverthelasttwodecadeshasidentifiedasignificantnumberoffailuremodes.Theperforma...[继续阅读]

    Pipelinesandrisersarelongandslenderstructureswherethestructuralbehaviourincludesnon-lineareffectsrelatedto:(1)Largedisplacements;(2)Non-linearpipe-soilinteractionforces;(3)Non-linearmaterialbehaviour;(4)Non-linearhydrodynamicloading;(5)Variableboundarycon...[继续阅读]

    AsnotedinSub-section4.5.3mostmodelsusedtopredictstressesduetobendingofhelicalstructuresarebasedontheassumptionthatnoendeffectsarepresent.Thismeansthatthestressesatonesectionisuniquelydeterminedbythekinematicquantitiesintermsoftheaxialstrain,torsionandcurv...[继续阅读]

    Thefollowingprocessesareappliedforsubseapipelinesandsystemsfabrication,see(Cary,1979)(Designationinnumbers,referenceto(ISO,2009)):1.Shieldedmetalarcwelding(SMAW111)Aconsumableelectrodecoatedwithflux,isusedtoproducetheweld.Anelectriccurrent,intheformofeith...[继续阅读]