简介：

简介：Themethodofcoupledmodeisintroducedforinvestigationofbi-staticdistantbottomreverberationofimpulsivesourceinshallowwater,whichwillnotcontradictwithprincipleofreciprocityinallcases.Andthemethodofmulti-polefordirectionalsourceisalsointroduced.Itshowsthatincaseoflayeredmedium,intensityofbi-staticbottomreverberationwilldeceaseaccordingtothecubicpowerofreceivingtimet,andthetransversespatialcorrelationofbottomreverberationisalittlegreaterthanlongitudinalcorrelationforequalseparationofreceivers,andbothvaryinformwiththereceivingtime.

简介：Inordertogetsomeusefulparametersforgridgenerationofcatamaran,theCFDsoftwareFLUENTisusedtoinvestigatethemaineffectsofgridgenerationonflowfieldcalculation.Theinfluencesofsomeelementsareinvestigatedwithaseriesofcalculationsinthepresentpaper,andsomealterativesareproposed.Theproposedalterativesbasedontheanalysisoftheeffectsareusedforacatamaranresistancecalculation,comparisonsofthecalculatedresultswithexperimentaldatashowgoodagreement.Itshowsthattheresearchresultofthispaperisusefulforthenumericalcalculationofcatamaran.

简介：Inordertoanalyzethespatialmaneuverabilityoftheremotelyoperatedunderwatervehicle(ROV),the6-DOFmotionmathematicmodeloftheROVwasfounded.HydrodynamicswereanalyzedbyusingtheTaylorseries.ThethrustersontheROVwerediscussed.Thispaperconsidersthreecasesofmotionsimulation:verticalmotion,rotationalmotionandZ-shapemotion.Aseriesofsimulationexperimentsshowedthatthe6-DOFmotionmathematicmodelwascorrectandreliable,andalsofitwiththescenesimulation.

简介：BasedonthetraditionalSmoothedParticleHydrodynamics(SPH)algorithm,thelinked-listsearchalgorithmcombinedwiththevariablesmoothinglengthandsquaresupportdomainwasputforwardtoimprovethecalculationefficiencyandguaranteethecalculationaccuracy.Thephysicalprocessofhighvelocityfragmentimpactonabroadsideliquidcabinwasprogrammedforsimulation.ThenumericalresultsagreedwellwiththoseofthegeneralsoftwareANSYSAUTODYN,whichverifiestheeffectivenessandfeasibilityofthenumericalmethod.Fromtheperspectiveoftheouterplatethicknessoftheliquidcabin,thewidthoftheliquidcabin,andincidentangleofthefragment,theinfluenceoftheseparametersonprotectivemechanismswasanalyzedtoprovideabasisforprotectivedesignofabroadsideliquidcabin.Resultsshowthattheinfluenceofouterplatethicknessisnotobvious;therefore,theconventionaldesigncanbeadoptedinthedesignoftheouterplate.Thewidthoftheliquidcabinhasagreatinfluenceontheresidualvelocityofthefragmentandthewidthoftheliquidcabinshouldbedesignedtobeaswideaspossibleunderthepremiseofmeetingotherrequirements.Thereisacertainincidentangleinwhichthevelocityattenuationofthefragmentismostobvious,andthehigh-pressurezoneneartheinnerplateisasymmetric.Theinnerplateofliquidcabinshouldbestrengthenedaccordingtothehullform,principaldimensions,andvulnerablepoints.

简介：Tosolvethedimensionallimitationsofphysicalmodelsintests,anequivalentwaterdepthtruncateddesignforaclassicalSPARworkingin913mwaterwasinvestigated.Thewaterdepthwasreducedto736mandthento552m.Asthiswasdone,themooringlinelengths,EAvalue,andmasspermeterwereadjusted.Truncationrulesandformulasforparametersandtruncationfactorswereproposed.SPARstaticcharacteristicsweremadetobeconsistentwiththoseatfullwaterdepth.Thenfurthertime-domaincoupledanalysiswascarriedoutfortheSPARwhenthemooringsystemexperiencedwaves.Themooringlinesweresimulatedbyquasi-staticmethod.Globalresponsesandmooringlineforceswerefoundtoagreewellwithtestresultsforaprototypeatthatwaterdepth.Thetruncationmethodprovedtoberobustandreliable.

简介：7月4日,国际海事组织（IMO）理事会第116届会议在英国伦敦召开,7月5日选举产生了新的副主席。经英国提议,巴西、肯尼亚、意大利、澳大利亚、土耳其、墨西哥、新加坡、俄罗斯、南非、孟加拉等多国附议,我国推荐的IMO理事会中方代表、交通运输部国际合作司副司长张晓杰顺利当选理事会副主席。这是我方首次当选,也是我国深度参与IMO工作的又一重要体现,将有助于我国作为A类理事国发挥更重要的作用。

简介：文章基于作者在中外合作建筑工程专业多年的教学实践，着重探讨了教师使用该教材进行双语教学的模式和学生学习英文课程的方法，进而提出使用英文课程提高教学效果相应的建议与对策。

简介：Thispaperpresentsananalyticalstudyontheinfluenceofedgerestrainingstiffnessonthetransversevibrationsofrectangularplatestructure.AnimprovedFourierseriesmethodwasemployedtoanalyzethetransversevibrationofplatestructurewithgeneralelasticallyrestrainedboundaryconditions.AlinearcombinationofadoubleFourierseriesandeightauxiliarytermswassoughtastheadmissiblefunctionoftheflexuraldisplacementoftheplate,eachtermbeingacombinationofapolynomialfunctionandasinglecosineseriesexpansion.Theauxiliarytermswereintroducedtoensureandimprovethesmoothnessoftheoriginaldisplacementfunctionanditsderivativesattheboundaries.Severalnumericalexamplesweregiventodemonstratethevalidityandaccuracyofthecurrentsolution.Theinfluencesoftranslationalandrotationalstiffnessonthenaturalfrequenciesandmodeshapesofplatewereanalyzedbynumericalresults.Theresultsshowthatthetranslationalstiffnesshasbiggerinfluenceonthenaturalfrequenciesthantherotationalstiffness.Itisgenerallywellknownthatlittlechangeoftherotationalstiffnesshaslittleinfluenceonthemodeshapesofplate.However,thecurrentworkshowsthataverylittlechangeofrotationalstiffnessvaluemayleadtoalargechangeofthemodeshapesofasquareplatestructure.

简介：船舶科技论文是专业性、工程应用性和科技性强的学术论文。由于很多作者很少受到专业的英文翻译训练,因而翻译的英文摘要不能准确表达原文含义,导致错误理解。文章根据船舶科技论文英文摘要的写作特点,在大量翻译实践的基础上,探讨了船舶科技论文英文摘要的翻译方法。

简介：这是继去年中国杯帆船赛之后，我第二次采访中国帆船帆板运动协会（“中帆协”）主席张小冬。今天是2018·中体产业·城市俱乐部国际帆船赛（第九届CCOR，于2018年9月5日-9日在青岛奥林匹克帆船中心举行）的第一个比赛日，张小冬回到她工作多年的青岛航校，在她一年前的青岛航校办公室里接受采访，状态非常地轻松。

简介：Thispaperfocusesontheresearchofasemi-submersibleplatformequippedwithaDP-assistedmooringsystem.BasedontheworkingprinciplesoftheDP-assistedmooringsystemandthemodeloftheplatformmotion,atimedomainsimulationprogramisappliedtoanalyzetheimpact,inthecaseofonelinefailure,ontheplatformmotion,powerconsumptionofthethrustersandthetensionofthemooringlines.Theresultsshowthat,underthe10-yearwinddominant,aonelinefailurewillhavelittleimpactonthetensionofthemooringlines.Whenthefailurelineiswindward,thepowerconsumptionwillincreasegreatlywithaweakenedpositionofaccuracy.Howeverwhenthefailurelineisleeward,thepowerconsumptionwillbereducedwithapartlystrengthenedpositionofaccuracy.

简介：Fishareabletomakegooduseofvortices.Inacomplexflowfield,manyfishcontinuetomaintainbothefficientcruisingandmaneuverability.Traditionalman-madepropulsionsystemsperformpoorlyincomplexflowfields.Withfish-likepropulsionsystems,itisimportanttopaymoreattentiontocomplexflowfields.Inthispaper,theinfluenceofvorticesonthehydrodynamicperformanceof2-Dflapping-foilswasinvestigated.Theflapping-foilheavedandpitchedundertheinfluenceofinflowvorticesgeneratedbyanoscillatingD-sectioncylinder.Anumericalsimulationwasrunbasedthefinitevolumemethod,usingthecomputationalfluiddynamics(CFD)softwareFLUENTwithReynolds-averagedNavier-Stokes(RANS)equationsapplied.Inaddition,dynamicmeshtechnologyandpostprocessingsystemswerealsofullyused.Thecalculationsshowedfourmodesofinteraction.Thehydrodynamicperformanceofflapping-foilswasanalyzedandtheresultscomparedwithexperimentaldata.Thisvalidatedthenumericalsimulation,confirmingthatflapping-foilscanincreaseefficiencybyabsorbingenergyfrominflowvortices.

简介：Windpowerhasmaderapidprogressandshouldgainsignificanceasanenergyresource,givengrowinginterestinrenewableenergyandcleanenergy.Offshorewindenergyresourceshaveattractedsignificantattention,as,comparedwithland-basedwindenergyresources,offshorewindenergyresourcesaremorepromisingcandidatesfordevelopment.Seawindsaregenerallystrongerandmorereliableandwithimprovementsintechnology,theseahasbecomeahotspotfornewdesignsandinstallationmethodsforwindturbines.Inthepresentpaper,basedonexperiencebuildingoffshorewindfarms,recommendedfoundationstyleshavebeenexamined.Furthermore,waveeffectshavebeeninvestigated.Thesplitinstallationandoverallinstallationhavebeenillustrated.Methodsappropriatewheninstallingasmallnumberofturbinesaswellasthoseusefulwheninstallinglargenumbersofturbineswereanalyzed.Thisinvestigationofinstallationmethodsforwindturbinesshouldprovidepracticaltechnicalguidancefortheirinstallation.

简介：Thecriticaltechnicalproblemofunderwaterbottomobjectdetectionisfoundingastablefeaturespaceforechosignalsclassification.Thepastliteraturesmorefocusonthecharacteristicsofobjectechoesinfeaturespaceandreverberationisonlytreatedasinterference.Inthispaper,reverberationisconsideredasakindofsignalwithsteadycharacteristic,andtheclusteringofreverberationinfrequencydiscretewavelettransform(FDWT)featurespaceisstudied.Inordertoextracttheidentifyinginformationofechosignals,featurecompressionandclusteranalysisareadoptedinthispaper,andthecriterionofseparabilitybetweenobjectechoesandreverberationisgiven.TheexperimentaldataprocessingresultsshowthatreverberationhassteadypatterninFDWTfeaturespacewhichdiffersfromthatofobjectechoes.Itisproventhatthereisseparabilitybetweenreverberationandobjectechoes.

简介：Foralargefloatingvesselinwaves,radiationdampingisnotanaccuratepredictionofthedegreeofrollunlikeotherdegreesoffreedommotion.Therefore,togettheknowledgeofrollmotionperformanceofdeepwaterpipelaycranevesselsandtokeepthevesselworkingsafety,thepaperpresentstherelationshipbetweenaseriesofdimensionlessrolldampingcoefficientsandtherollresponseamplitudeoperator(RAO).Byusingtwokindsofempiricaldata,therolldampingisestimatedinthecalculationflow.Aftergettingtherolldampingcoefficientfromthemodeltest,apredictionofrollmotioninregularwavesisevaluated.Accordingtothewaveconditionintheworkingregion,shorttermstatisticsofrollmotionarepresentedunderdifferentwaveparameters.Moreover,therelationshipbetweenthemaximalrollresponseleveltopeakspectralwaveperiodandtherolldampingcoefficientisinvestigated.Resultsmayprovidesomereferencetodesignandimprovethiskindofvessel.

简介：Inunderwatertargetdetection,thebottomreverberationhassomeofthesamepropertiesasthetargetecho,whichhasagreatimpactontheperformance.Itisessentialtostudythedifferencebetweentargetechoandreverberation.Inthispaperbasedontheuniqueadvantageofhumanlisteningabilityonobjectsdistinction,theGammatonefilteristakenastheauditorymodel.Inaddition,time-frequencyperceptionfeaturesandauditoryspectrafeaturesareextractedforactivesonartargetechoandbottomreverberationseparation.Thefeaturesoftheexperimentaldatahavegoodconcentrationcharacteristicsinthesameclassandhavealargeamountofdifferencesbetweendifferentclasses,whichshowsthatthismethodcaneffectivelydistinguishbetweenthetargetechoandreverberation.

简介：路径规划是自主式水下潜器(AUV)导航研究的重要课题,AUV可用于未知环境如海洋空间探测.在大范围海洋环境中,应用蚁群优化原理对自主式水下潜器的全局路径规划问题进行了研究.引入栅格建模方法建立了蚁群可视图模型,设计了蚁群信息素更新规则;给出了蚁群全局路径规划的操作步骤;针对蚁群规划路径不平滑问题,设计了切割算子和插点算子.仿真实验结果表明,蚁群全局规划算法非常适合于求解复杂环境中的规划问题,规划时间短、路径平滑,其原型系统可应用于非结构化无人环境监测。

简介：Basedontheprincipleofimpedancemismatching,theperformanceofrigidvibrationisolationmassinimpedingvibrationwavepropagationwasdiscussedfromtheperspectiveofwaveapproach.BasedonFEM,theinfluenceofitsweightaswellasthecross-sectionshapeparametersontheisolationperformanceofrigidvibrationisolationmasswasstudiedthroughnumericalsimulation.Theresultsshowthatrigidvibrationisolationmasscaneffectivelyimpedethepropagationofthemediumandhighfrequencyvibrationwaves,andtheheavierthevibrationisolationmass,thebettertheisolationperformance.Forlowfrequencywaves,thevibrationisolationeffectisnotsoobvious;forarectangularvibrationisolationmass,theisolationperformancecouldbeeffectivelyimprovedbyincreasingthecross-sectionheightandreducingthecross-sectionwidth.Ausefulreferencewasprovidedfortheapplicationofrigidvibrationisolationmassestothevibrationisolationandnoisereductionofshipstructure.

简介：AmethodofreliabilityanalysisbasedonadirectstrengthcalculationemployingthevonMisesstressfailurecriterionispresentedhere.Theshorttermstraindistributionsofshiphullstructuralcomponentsareidentifiedthroughthestatisticalanalysisofthewave-inducedstrainhistoryandthelongtermdistributionsbytheweightedsummationoftheshorttermstraindistributions.Thewave-inducedlongtermstraindistributioniscombinedwiththestillwaterstrain.Theextremestraindistributionoftheresponsestrainisobtainedbystatisticalanalysisofthecombinedstrains.ThelimitstatefunctionofthereliabilityanalysisisbasedonthevonMisesstressfailurecriterion,includingtherelateduncertaintiesduetothequalityofthematerialandmodeluncertainty.ThereliabilityindexiscalculatedusingFORMandsensitivityanalysisofeachvariablethathaseffectsonthereliabilityisalsodiscussed.