COMMITTEE III.2-FATIGUE AND FRACTURE

47517thINTERNATIONALSHIPANDOFFSHORESTRUCTURESCONGRESS16-21AUGUST2009SEOUL,KOREAVOLUME1COMMITTEEIII.2FATIGUEANDFRACTURECOMMITTEEMANDATEConcernforcrackinitiationandgrowthundercyclicloadingaswellasunstablecrackpropagationandtearinginshipandoffshorestructures.Dueattentionshallbepaidtopracticalapplicationandstatisticaldescriptionoffracturecontrolmethodsindesign,fabricationandservice.Considerationistobegiventothesuitabilityanduncertaintyofphysicalmodels.COMMITTEEMEMBERSChairman:A.M.HornM.R.AndersenM.BiotB.BohlmannS.Mahérault-MouginJ.KozakN.OsawaY.S.JangH.RemesJ.RingsbergJ.vanderCammenKEYWORDSFatigue,FractureMechanics,ProbabilisticMethods,Materials,RulesandGuidelines,FitnessforServices,InspectionandLifeExtensionISSCCommitteeIII.2:FatigueAndFracture477CONTENTS1.INTRODUCTION...............................................................................................4792.STATEOFTHEARTOFLIFEPREDICTIONMETHODS...........................4802.1Low-cycle,High-cycleandUltra-high-cycleApproaches....................4822.2CumulativeFatigueDamagebasedonS-NCurves...............................4832.2.1NominalStressApproach........................................................4842.2.2StructuralStressApproach......................................................4842.2.3EffectiveNotchStressApproach............................................4892.3NotchStrainApproach(InitiationPhase)..............................................4912.4FractureMechanicsApproach(PropagationPhase)..............................4922.4.1CrackGrowthRateModels.....................................................4922.4.2VariousSpecialPhenomenarelatingtoFatigueCrackPropagation..............................................................................4952.4.3UnstableCrackPropagation....................................................4962.5FractureMechanicsEvaluationforStrainslargerthan0.5%...............4962.6RelationshipbetweenS-NandFractureMechanicsApproaches.........4992.6.1FractureDatabyTesting.........................................................5003.PROBABILISTICAPPROACHESANDMULITIAXIALFATIGUE...........5033.1ProbabilisticApproach...........................................................................5033.1.1ProbabilisticS-NApproach.....................................................5043.1.2ProbabilisticFractureMechanicsApproach...........................5053.2Multiaxialfatigue....................................................................................5064.FACTORSINFLUENCINGFATIGUE............................................................5074.1ResidualandMeanStressEffect............................................................5074.1.1FractureMechanics-BasedApproach.....................................5084.1.2S-NbasedApproach................................................................5094.2EffectofLoadSequences.......................................................................5104.3ThicknessandSizeEffect......................................................................5114.4EffectofCorrosiveEnvironmentandTemperature...............................5134.5Design.....................................................................................................5154.6Fabrication..............................................................................................5164.7FatigueImprovementMethodsandMaterialSelection.........................5175.DEVELOPMENTSINMATERIALSANDNEWSTRUCTURES................5195.1MaterialforColdClimateCondition.....................................................5195.1.1BrittleFracture.........................................................................5205.2NewSteelwithImprovedCrackGrowthProperties(FCA,FMDPSteels)……………………………………………………………………….5215.3ExtraHighStrengthSteelsandStainlessSteel......................................5235.4OtherMaterials.......................................................................................5255.4.1Titanium...................................................................................5255.4.2Aluminium...............................................................................5265.4.3Nickel.......................................................................................5275.4.4CorrosionResistantAlloys(CRA)Material...........................5285.4.5Duplex......................................................................................529478ISSCCommitteeIII.2:FatigueAndFracture5.4.6Composite................................................................................5295.5Newmaterials.........................................................................................5295.6LaserWeldedandCompositeStructures...............................................5306.FATIGUEDESIGNMETHODSFORSHIPANDOFFSHORESTRUCTURES5326.1FatigueDesignCodesforShipStructures.............................................5326.1.1OverviewofFatigueAnalysisMethodologiesusedforStressResponseAssessment..............................................................5326.1