Nonlinearwaveloadscaninducelow-frequencyandhigh-frequencyresonancemotionsofamooredplatformindeepwater.Fortheanalysisofthenonlinearresponseofanoffshoreplatformundertheactionofirregularwaves,themostwidelyusedmethodinpracticeistheCumminsmethod,inwhichthesecond-orderexcitingforcesinthetimedomainarecomputedbyatwo-termVolterraseriesmodelbasedonincidentwaves,first-orderbodymotionresponse,andquadratictransferfunctions(QTFs).QTFsarebichromaticwavesactingonabodyandarecomputedinthefrequencydomaininadvance.Formovingbodies,QTFsarerelatedtothefirst-orderbodyresponse,whichistobedeterminedinthesimulationprocessofbodymotionresponsebutisunknowninthecomputationprocedureofQTFs.Insolvingthisproblem,TengandCong(2017)proposedamethodtopidetheQTFsintodifferentcomponents,whichareunrelatedtothebodyresponse.WiththeapplicationofthenewQTFcomponents,amodifiedCumminsmethodcanbedevelopedforthesimulationofthenonlinearresponseofamooredfloatingplatform.Thispaperpresentsareviewofthetheory.
