简介：台湾酝酿建立弹性学制为了确立２１世纪台湾的教育政策，在１９９４年６月召开的全台教育会议上，重点讨论了建立弹性学制的问题，对现行学制要进行“全面检讨，大幅调整”已成为全体代表的共识。台湾现行的学制，即所谓“六三三四”学制（小学６年，初中３年，高中３年，...

简介：文章基于夹层结构的材料性能和力学理论,通过比较夹层板在碰撞仿真中的建模技术,探讨适合于夹层结构的建模方法。对夹层结构与普通钢板耐撞性能进行比较,研究其整体的耐撞性能。通过对钢-聚氨酯夹层结构的分析,研究整体结构的耐撞性,为研究钢-聚氨酯夹层结构的船体耐撞结构设计提供研究基础。

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

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简介：近年来，随着深海石油工业的发展，立管的涡激振动现象越来越受学者们关注．使用RANS方程求解器，并结合SSTκ-ω湍流模型，对横向和流向自然频率比为1的低质量比弹性支撑圆柱体的两自由度运动进行了数值模拟，计算雷诺数范围为5300至32000．采用四阶Runge—Kutta方法求解柱体的振动方程．并结合近期物理实验结果对升力系数、阻力系数、位移和尾涡模式进行了详细比较和讨论．较好地再现了试验观察到的锁定、迟滞、差拍等现象。

简介：Theproblemofwaterwavescatteringbyathinverticalelasticplatesubmergedinuniformfinitedepthwaterisinvestigatedhere.TheboundaryconditionontheelasticplateisderivedfromtheBernoulli-Eulerequationofmotionsatisfiedbytheplate.UsingtheGreen’sfunctiontechnique,fromthisboundarycondition,thenormalvelocityoftheplateisexpressedintermsofthedifferencebetweenthevelocitypotentials(unknown)acrosstheplate.Thetwoendsoftheplateareeitherclampedorfree.Thereflectionandtransmissioncoefficientsareobtainedintermsoftheintegrals’involvingcombinationsoftheunknownvelocitypotentialonthetwosidesoftheplate,whichsatisfythreesimultaneousintegralequationsandaresolvednumerically.Thesecoefficientsarecomputednumericallyforvariousvaluesofdifferentparametersanddepictedgraphicallyagainstthewavenumberinanumberoffigures.

简介：Sloshingphenomenonintheliquidcargocarriershascaughttheattentionofresearchersastheinteractionbetweenthesloshingwavesandstructureisoneofthekeypointanddifficultyinthestudyofsloshing.Inthispaper,wecapturedthefreesurfacewithavolumeoffluid(VOF)methodandthencalculatedthemotionsandresponsesofthestructurebyadoptingtheReynolds-averagedNavier-Stokes(RANS)equationsforthewholefluiddomain.Withtheuseofuserdefinedfunctions(UDF)inFluent,theinteractionbetweenfluidandstructurewasthensimulated.Asareasonablesimplification,theauthorsstudiedtheresponseofasinglecantileverinatankundersloshingloads;Furtherstudyshouldpaymoreattentiontothemechanismsofinteractionbetweensloshingwavesandelasticstructures.

简介：文章介绍了快速绘制梁的内力图的教学方法，利用该方法学生能够快速掌握绘制内力图的规律，能在不列方程情况下，迅速地绘出复杂外力作用下梁的内力图，并以实例说明该方法的有效性。

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简介：文章结合某桥梁工程的施工,对现浇连续箱梁跨城市道路的门洞支架进行了设计,并着重对门洞支架的强度、刚度及稳定性进行了验算以确保工程施工的安全,同时阐述了门洞支架搭设的施工要点,为类似工程施工提供了借鉴。

简介：2月1日,交通部海事局党委书记梁晓安到东港海事处督导电煤运输工作。在听取东港海事处关于保障电煤运输工作的汇报后,他肯定了东港海事处为保障电煤运输所采取的措施，并为东港海事处题词——“中国海事电煤运输保障第一处”。梁书记强调，保障电煤运输畅通要政治意识到位，大局意识到位，责任意识到位，要做打硬仗的长期准备，

简介：Theextendingofacantileverandtransversemovingofadrillingfloorenablethejack-uptooperateinseveralwellpositionsaftertheJack-uphaspitched.Thecantileverallowableloadnephogramisthecriticalreferencewhichcanevaluatethejack-up’sdrillingability,designthecantileverstructureandinstructajack-upmanagertomaketheoperationssafe.Theintentofthispaperistoexploretheinterrelationshipsbetweenthecantileverposition,drillingfloorandtheloadsincludingwindforce,thestandset-backweightetc.,throughanalyzingthestructureandloadcharacteristicsofthex-typecantileverandthesimplifiedmechanicsmodelwiththerestrictionofthemaximummomentcapacityofthecantileversinglesidebeam.Referringtoseveraltypicalpositiondesignsloadvalues,thecantileverallowableloadnephogramisobtainedbyusingthesuitableinterpolationmethod.Thepapergivesamethodforcantileverallowableloaddesign,whichisprovedreliableandeffectivebythecalculationexample.

简介：Acomplianttowerismodeledasapartiallydry,partiallytapered,dampedTimoshenkobeamwiththesuperstructuremodeledasaneccentrictipmass,andanon-classicaldampedboundaryatthebase.Thefoundationismodeledasacombinationofalinearspringandatorsionalspring,alongwithparallellinearandtorsionaldampers(Kelvin-Voigtmodel).Thesuperstructureaddstothekineticenergyofthesystemwithoutaffectingthepotentialenergy,therebyreducingthenaturalfrequencies.Theweightofthesuperstructureactsasanaxialcompressiveloadonthebeam,reducingitsnaturalfrequenciesfurther.Theemptyspacefactorduetothetruss-typestructureofthetowerisincluded.Theeffectofsheardeformationandrotaryinertiaareincludedinthevibrationanalysis;withthenon-uniformbeammode-shapesbeingaweightedsumoftheuniformbeammode-shapessatisfyingtheendcondition.TheweightsareevaluatedbytheRayleigh-Ritz(RR)method,andverifiedusingfiniteelementmethod(FEM).Theweightofthesuperstructureactsasanaxialcompressiveloadonthebeam.Kelvin-Voigtmodelofstructuraldampingisincluded.Apartofthestructurebeingunderwater,thevirtualaddedinertiaisincludedtocalculatethewetnaturalfrequencies.Aparametricstudyisdoneforvariousmagnitudesoftipmassandvariouslevelsofsubmergence.ThecomputationalefficiencyandaccuracyoftheRayleigh-Ritzmethod,ascomparedtotheFEA,hasbeendemonstrated.Theadvantageofusingclosed-formtrialfunctionsisclearlyseenintheefficacyofcalculatingthevariousenergycomponentsintheRRmethod.