縱浪中船舶參數(shù)激勵非線性隨機橫搖研究.pdf

1、天津大學(xué)碩士學(xué)位論文縱浪中船舶參數(shù)激勵非線性隨機橫搖研究姓名：鄺艷香申請學(xué)位級別：碩士專業(yè)：船舶與海洋結(jié)構(gòu)物設(shè)計制造指導(dǎo)教師：唐友剛20070101ABSTRACTParametricrollinginthelongitudinalwavesisallimportantmodeleadingtoshipcapsizingandrelatestomanydisastersThispaperstudiesonthepredictionmet

2、hodofparametricexcitationinregularandrandomlongitudinalwaves，andinvestigatestheconditionsonwhichtheparametricrollingOccursaswellasthedynamiccharacteristicsoflargeamplituderollmotionsTheparametricallyexcitedrollingequatio

3、nofshipsinlongitudinalwavesissetupwithconsideringtheinfluenceofmetacentricheightvaryingwithtimeByassumingquasistaticequilibriumofheaveandpitchmotions，themethodforthecalculationofmetacentricheightfluctuationsisderivedfors

4、hipsinregularandrandomwavesThemethodofmultiplescalesisusedtOobtaintheapproximateanalyticalsolutionsoftheregularcase，andtOdeterminethestableandinstablespaceofthetrivialsolutionsfromwhichwecandeterminetheconditionsofparame

5、tricrollingTheDarametricrollmotionsinregularandrandomwavesarenumericallysimulatedbyusingRungeKuttaalgorithmfordifferentnavigationspeeds，andthedynamiccharacteristicsoflargeamplituderollmotionsareinvestigatedThemethodofsto

6、chasticaveragingandFPKequationareappliedtoyieldtheprobabilitydensityfunctionofstochasticmeanvaluearealSollamplitudeprocessTheprobabilitydistributionfunctionandderivedbyintegrationtherollamplitudeprobabilitydensityfunctio

7、nThenumericalandanalyticalresultsshowthatparametricrollingexistsbothinregularandrandomhighwavesWhentheshipwaveencounterfrequencyISnearthetwiceofrollnaturalfrequency，theprincipalparametricresonanceoccurs，andthelargeamplit

8、uderollingarisesTherollmotiondecaysotherwiseThestochasticDar鋤etricrollingamplitudechangesabruptlyandismoredifficulttopredictthaninregularwavesbecauseofthe行equencycharacteristicsofrandomwavesAlsothejumpphenomenonisfoundin

9、theparametricrollingThejumpofrollamplitudewillrcsuItinthelostofmotionstabilityandtheincreaseofshipcapsizeprobabilityKEYWORDS：longitudinalwaves，parametricexcitation，metacentricheightfluctuation，stochasticrollamplitude，pro