简介:Withtheincreasingimportanceofoceanexploitation,providinganti-rollingstabilityforshipsatanchorhasbecomemoreandmoreimportant.Thelift-generationtheoryoftraditionalfinstabilizersisbasedonincomingflowvelocity,whichisnotsuitableforexplainingliftgeneratedatanchor.Weanalyzednon-steadyflows,withforcesonfinstabilizersgeneratedbynon-incomingflowvelocityconditions,andgaveanewlift-generationmodel.Thecorrectnessofthemodelwasprovenbycomparingexperimentalresultsoffinstabilizermotionundernon-incomingvelocityconditionsfromthefluidcomputationsoftwarewiththatfromtheemulatorofthelift-generationmodel.Finally,themodelwasusedinananti-rollingsystemonashipandthereductionofrollwasmuchbetterthanwhatcouldbeachievedbypassiveanti-rollingtanks.
简介:以便在ships'ballast水上验证电解处理的有效性,实验被一个实验性系统在实验室执行。当轮船的碎石流水,有不同水藻的不同集中的未加工的海水和海水被模仿。如果它被电解与5mg/L的起始的剩余氯集中对待,在未加工的海水的Thealgae能被打死。如果有一个种水藻(Nitzschiaclosterum,Dicrateriaspp,或Pyramidomonnassp.10~5cells/mL)的海水被电解与5mg/L的起始的剩余氯集中对待,水藻能被消毒。如果有一个种水藻(Dunaliellasp,Platymonas或小球藻spp)的海水被electrolyzing直接与4mg/L的起始的剩余氯集中对待,立刻的死亡随着不同水藻的集中变化。在72个小时以后,在所有对待的样品,然而,没有现场海藻的房间,发现。
简介:以便在轮船提高旅客撤退模拟的真实性和精确性,一个新多格子模型根据一个传统的细胞的自动机模型被建议。在新模型,更好的格子被使用,在行人之中或在行人和构造之间的力量的相互作用被考虑,并且在多水平的静态的地板地退出环境被简化进舱和出口静电干扰地板地。与传统的细胞的自动机模型相比,多格子模型提高了旅客轨道的连续性和边界资格的精确。旅客的脱臼分发以及轨道的部分重叠的功能由于拥挤被认识到。而且,作为一个例子拿典型的舱环境,二个模型被用来在一样的条件下面分析旅客撤退。二个模型模仿的旅客撤退的法律是类似的,这被发现,当模拟真实性和精确性被多格子模型提高时。
简介:Themainfocusisnonlinearmodel-baseddynamicpositioning(DP)controlsystemdesign.Anonlinearuniformglobalexponentialstability(UGES)observerproducesnoise-freeestimatesoftheposition,theslowlyvaryingenvironmentaldisturbancesandthevelocity,whichareusedinaproportional-derivative(PD)+feedforwardcontrollaw.Thestabilityofthisobserver-controllersystemisprovedbyintroducingaspecificnonlinearcascadedsystem.ThesimulationresultshavesuccessfullydemonstratedtheperformanceofdesignedDPcontrolsystem.
简介:Concernaboutglobalclimatechangeisgrowing,andmanyprojectsandresearchersarecommittedtoreducinggreenhousegasesfromallpossiblesources.InternationalMaritimeOrganization(IMO)hassetatargetof20%CO2reductionfromshippingby2020andalsopresentedaseriesofcarbonemissionreductionmethods,whichareknownasEnergyEfficiencyDesignIndex(EEDI)andEnergyEfficiencyOperationIndicator(EEOI).Reviewsoncarbonemissionreductionfromallindustriesindicatethat,CarbonCaptureandStorage(CCS)isanexcellentsolutiontoglobalwarming.Inthispaper,acomprehensiveliteraturereviewofEEDIandEEOIandCCSisconductedandinvolvesreviewingcurrentpolicies,introducingcommontechnologies,andconsideringtheirfeasibilitiesformarineactivities,mainlyshipping.Currentprojectsarealsopresentedinthispaper,therebyillustratingthatcarbonemissionreductionhasbeenthesubjectofattentionfromallovertheworld.TwocaseshipstudiesindicatetheeconomicfeasibilityofcarbonemissionreductionandprovideaguideforCCSsystemapplicationandpracticalinstallationonships.
简介:Thewave-inducedverticalshipmotionsandbendingmomentsofadoublehull-oiltankerinrealisticfloodingconditionsarestudied.Thescenariosinvestigatedarerepresentedbywateringressintothestarboardballasttanksforcollisiondamagecasesandbothstarboardandportsideballasttanksforgroundingsituations.Seakeepingcomputationsareperformedforeightdamagescenariosandfortheintactcondition,eachcorrespondingtodifferentchangesindisplacement,trim,andheel.Foreachofthedamageconditions,transferfunctionsofverticalmotionsandloadsarecalculatedusingapotentiallinear3Dpanelhydrodynamiccodeinthefrequencydomainthatincludeseffectofthemotionofthewaterinfloodedtanks.AMATLABcodeisdevelopedtofacilitateautomatedhydrodynamicsimulationofmanydamagescenarios.Verificationofseakeepingresultsisperformedbycomparingtransferfunctionswithresultsofthepreviousstudy.Wave-inducedverticalresponsesofdamagedshiparethencomparedtothoseofintactshipusingtwospectral-basedmethodsoriginatingfromuncertaintyanalysisofwaveloads,whichareconvenienttoolstoassessconsequencesofdamageonshort-termshipresponses.Generally,observedtrendisthatverticalwave-inducedresponsesofdamagedshipconvergetowardthoseofintactshipwithincreasingwaveperiod.Fairlysmalldifferencesbetweenresponsesofasymmetricallydamagedshipwithrespecttothesymmetricalincomingwavedirectionsarefound.Theresultsofthestudyareanefficientmethodforseakeepingassessmentofdamagedoiltankersandtheframeworkforevaluatingconsequencesofdamagescenarios,headingangles,andseaconditionsonseakeepingresponsesofdamagedships.Theresultscanbeusedtodecideiftheintactshipmodelcanbeusedinsteadofthedamagedonefortheemergencyresponseprocedureorfortheriskassessmentstudieswhenmodelingandcomputationaltimerepresentimportantlimitations.
简介:在现在的分析,在数字模拟使用的几个参数在综合研究被调查在这模拟的进程和结果上获得他们的影响。学习的参数是元素明确的表达,磨擦系数,和材料模型。用非线性的有限元素方法的数字模拟被进行为几种碰撞情形生产虚拟试验性的数据。当真实试验性的数据,和这些被用来验证方法,碰撞在一个真实事故案例中引起的模式和尺寸损坏被假定。执行的元素模型学习显示Belytschko-Tsay元素明确的表达应该在虚拟实验为使用被推荐。为包含的材料的磨擦系数的真实价值在模拟被使用,这被推荐。为材料模型的学习,有高收益力量的材料的申请在方面壳结构为使用被推荐。
简介:在海洋的结构合成的增强的眼镜纤维的使用正在变得更普通,特别地由于潜在的重量积蓄。在增强的聚合物(GRP)上层建筑和钢壳形成了的眼镜纤维之间的关节的机械反应被检验并且随后修改了通过当模特儿并且测试的一个联合程序改进性能。一个有限元素的模型被开发预言关节的反应。模型在在不同材料,进步损坏,大变丑理论,和一种非线性的压力紧张关系之间的接口考虑接触。预言进步失败,分析联合Hashin失败标准和最大的压力失败标准。结果表演压力反应在力量上有大影响并且关节适用。Balsawood钢接口被证明对关节的机械行为批评。在试验性的结果和数字预言之间的好同意被观察。
简介:Sincetheresearchofflareslammingpredictionisseldomwhenparametricrollinghappens,wepresentanefficientapproximationmethodforflareslamminganalysisoflargecontainershipsinparametricrollingconditions.Weadopta6-DOFweaklynonlineartimedomainmodeltopredicttheshipmotionsofparametricrollingconditions.Unlikepreviousflareslamminganalysis,ourproposedmethodtakesrollmotionintoaccounttocalculatetheimpactangleandrelativeverticalvelocitybetweenshipsectionsonthebowflareandwavesurface.WeusetheWagnermodeltoanalyzetheslammingimpactforcesandtheslammingoccurrenceprobability.Throughnumericalsimulations,weinvestigatethemaximumflareslammingpressuresofacontainershipfordifferentspeedsandwaveconditions.Tofurtherclarifythemechanismofflareslammingphenomenainparametricrollingconditions,wealsoconductreal-timesimulationstodeterminetherelationshipbetweenslammingpressureand3-DOFmotions,namelyroll,pitch,andheave.
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简介:Apathfollowingcontrollerisdevelopedforunderactuatedshipswithonlysurgeforceandyawmomentavailabletofollowapredefinedpath.Theproposedcontrollerisbasedonnonswitchanalyticmodelpredictivecontrol.Itisshownthattheoptimalcontrollawforanonlinearpathfollowingsystemwithill-definedrelativedegreeiscontinuousandnonsingular.Theproblemofill-definedrelativedegreeissolved.Thepath-followingabilityofthenonlinearsystemisguaranteed.Numericalsimulationsareprovidedtodemonstratetheeffectivenessoftheproposedcontrollaw.
简介:在时间域的领域分解和匹配的方法为模仿在波浪进展的轮船的运动被构画出。流动域被想象的控制表面分解成内部、外部的域,并且当短暂格林函数方法在外部域被使用时,Rankine来源方法被用于内部域。二个起始的边界价值问题在控制表面上被匹配。相应数字代码被开发,并且为系列60轮船和S175货柜船在头海进展的增加的群众,波浪激动力量和轮船运动,被介绍并且验证。当数字结果与试验性的数据和另外的引用相比时,一个好协议被获得了。它证明因为面板discretization,现在的方法在数字计算期间在内部领域仅仅是更有效的,并且好数字稳定性被证明与闪光关于轮船避免分叉问题。