简介:Foralargefloatingvesselinwaves,radiationdampingisnotanaccuratepredictionofthedegreeofrollunlikeotherdegreesoffreedommotion.Therefore,togettheknowledgeofrollmotionperformanceofdeepwaterpipelaycranevesselsandtokeepthevesselworkingsafety,thepaperpresentstherelationshipbetweenaseriesofdimensionlessrolldampingcoefficientsandtherollresponseamplitudeoperator(RAO).Byusingtwokindsofempiricaldata,therolldampingisestimatedinthecalculationflow.Aftergettingtherolldampingcoefficientfromthemodeltest,apredictionofrollmotioninregularwavesisevaluated.Accordingtothewaveconditionintheworkingregion,shorttermstatisticsofrollmotionarepresentedunderdifferentwaveparameters.Moreover,therelationshipbetweenthemaximalrollresponseleveltopeakspectralwaveperiodandtherolldampingcoefficientisinvestigated.Resultsmayprovidesomereferencetodesignandimprovethiskindofvessel.
简介:1979年,中国第一批29名海员跨出国门走向国际市场,开启了中国海员外派的新篇章。30多年来,中国的海员外派事业经历了"起步探索"、"快速发展"及"相对稳定"的三个发展阶段,积累了一定的专业外派经验,取得了较好的经济和社会效益。一、影响中国海员外派行业发展两大因素据统计,我国到2013年底拥有注册海员约57万,外派机构230余家,每年向国际航运市场派出海员逾10万人次,但是在外海员仅5-6万人(这其中包括了派往中资企业方便旗船的人数),合作客户主要集中在港、澳、台和东南亚地区,欧、美地区的客户数量不多,这与我国作为世界人口大国,拥有丰富的人力资源优势和航海培训院校资源的优势格格不入,这些优势未能得到充分体现。
简介:AmethodofreliabilityanalysisbasedonadirectstrengthcalculationemployingthevonMisesstressfailurecriterionispresentedhere.Theshorttermstraindistributionsofshiphullstructuralcomponentsareidentifiedthroughthestatisticalanalysisofthewave-inducedstrainhistoryandthelongtermdistributionsbytheweightedsummationoftheshorttermstraindistributions.Thewave-inducedlongtermstraindistributioniscombinedwiththestillwaterstrain.Theextremestraindistributionoftheresponsestrainisobtainedbystatisticalanalysisofthecombinedstrains.ThelimitstatefunctionofthereliabilityanalysisisbasedonthevonMisesstressfailurecriterion,includingtherelateduncertaintiesduetothequalityofthematerialandmodeluncertainty.ThereliabilityindexiscalculatedusingFORMandsensitivityanalysisofeachvariablethathaseffectsonthereliabilityisalsodiscussed.