简介：Theunbondedflexiblepipeofeightlayers,inwhichallthelayersexceptthecarcasslayerareassumedtohaveisotropicproperties,hasbeenanalyzed.Specifically,thecarcasslayershowstheorthotropiccharacteristics.Theeffectiveelasticmoduliofthecarcasslayerhavebeendevelopedintermsoftheinfluenceofdeformationtostiffness.Withconsiderationoftheeffectiveelasticmoduli,thestructurecanbeproperlyanalyzed.Alsotherelativemovementsoftendonsandrelativedisplacementsofwiresinhelicalarmourlayerhavebeeninvestigated.Athree-dimensionalnonlinearfiniteelementmodelhasbeenpresentedtopredicttheresponseofflexiblepipesunderaxialforceandtorque.Further,thefrictionandcontactofinterlayerhavebeenconsidered.Comparisonbetweenthefiniteelementmodelandexperimentalresultsobtainedinliteraturehasbeengivenanddiscussed,whichmightprovidepracticalandtechnicalsupportfortheapplicationofunbondedflexiblepipes.

简介：Anonlineardynamicanalysismodelisestabilishedonthebasisof"lumpedmass"approach,whichtakestheinfluenceofthefluidflowwithinthepipeintoconsideration.Numericalresultsarecomparedwiththepublishedworks,andtheeffectsofinternalfluidflow,internalpressure,dyanmicsaswellasthenonlinearcharacteristicsonthebehaviorofflexiblerisersarediscussed.Fromthiswork,someusefulconclusionsaredrawn.

简介：ThetransientresponsetolongitudinalimpactofflexiblerodswithHertzcontactiscloselyrelatedtotheextentofdeformationswithdifferentimpactparameters.BymeansofLS-DYNA,fordifferentradiusanddifferentspeeds,thelongitudinalimpactofahammerwitharoundedendonadrillrodisnumericallysimulatedinthisarticle.Simulationsdemonstratethatthereisanobviousdif-ferencebetweenanalyticalsolutionandnumericalsolutiononconditionofshortcurvatureradius.Inthecircumstancecontactpressureincreases,theboundaryoftheyieldzoneexceedsthatofthecontactzone,andthesignificantplasticdeformationreducestheintensityofcontactpressurepulse.Contactforce-timecurvesinloadingandunloadingphasesshiftdown.Thenumericalsolutionisingoodagree-mentwithanalyticalsolutiononconditionoflargecurvatureradiusandimpactspeeds.Thedeforma-tionofyieldregionisconstrainedbythesurroundingelasticregionandnosignificantplasticdeforma-tionappears.

简介：象腹股沟，纵的堤和防波堤那样的水力的结构在管理和水交通工程在家和国外投射的水里是普通的，它长有由稳固的集体结构的形式统治了。与是的刷子和石头造材料，这种结构有明显的工程效果。然而，它不仅要求巨大的大写的投资，而且在生态的环境上有否定影响。推迟的灵活水坝是一项创新工程措施，和水坝能目前被发现的这种类型的很少理论、试验性的研究。这篇论文学习机制和这个水坝的形状特征并且在三种形式之中为转变获得灵活水坝，漂流快活表示，和条件的动态平衡方程在水下水坝的形状。结果在设计申请是珍贵的并且能为持续开发由于特殊设计哲学，环境上的小否定效果和一致性为未来工作被用作引用。

简介：有流动上的不同安排密度的纵的酒吧介绍的不同沉没障碍和一个scour洞的形态学的效果在清楚的水条件下面被调查。声学的Dopplervelocimetry(副词)数据被使用阴谋三维的速度和狂暴的轮廓的垂直分布。试验性的结果显示那安排密度(能也代表孔)，结构的材料(灵活或稳固)，并且sidewall效果是影响狂暴的动能和形态学的主要因素搜索洞。为灵活植被，床表面附近的最大的狂暴的动能与安排密度增加了。为一样的结构，深度和scour洞的侧面的扩大的大小也与安排密度增加了。因为偏转和安排密度，灵活植被减少了scour洞的深度。大量scour在结构在灵活植被比作很好那些的固体的在上游、中间的节发现了。多孔的灵活植被的偏转下游地搬运了狂暴的动能，在沉积床附近减少了狂暴的动能，并且增加了酒吧的稳定性。灵活植被酒吧能在正常条件下面保护河岸和一条河的床，使他们成为在河的管理和恢复的一个好其他的图案。

简介：这份报纸论述是可扩展的因为地理上散布了的联机混合测试系统测试的一个基础。这个系统由通常过去常让周期的测试装载测试基础到目标排水量或目标力量上的一套设备组成。由于他们的坚韧性和可移植性，常规装载设备的单个集合能被搬运并且重新设置认识到在地理上遥远的实验室的物理装载。另一个呼吁的特征是对在各种各样的性能期间在僵硬有大不同的标本特别地合适的混合控制上演的灵活排水量力量。进行一个基础联机混合测试，一个可扩展的框架被开发，它与一个概括接口被装备包含每个基础。用各种各样的结构的程序代码的多重测试基础和分析基础能在单个框架以内被提供，简单地与边界排水量和力量连接了。一个协调人程序被开发在所有基础兼容机和equilibrated之中保留边界。一个基于因特网的数据交换计划也被设计在与不同软件环境装备的计算机之中转移数据。一系列联机混合测试被介绍，并且联机混合测试系统的可移植性，灵活性，和可扩展性被表明。

简介：Inordertoaccountforrigid-flexiblecouplingeffectsoffloatingoffshorewindturbines,anonlinearrigid-flexiblecoupleddynamicmodelisproposedinthispaper.Theproposednonlinearcoupledmodeltakesthehigher-orderaxialdisplacementsintoaccount,whichareusuallyneglectedintheconventionallineardynamicmodel.Subsequently,investigationsonthedynamicdifferencesbetweentheproposednonlineardynamicmodelandthelinearoneareconducted.Theresultsdemonstratethatthestiffnessoftheturbinebladesintheproposednonlineardynamicmodelincreaseswithlargeroverallmotionsbutthatinthelineardynamicmodeldeclineswithlargeroverallmotions.Deformationofthebladesinthenonlineardynamicmodelismorereasonablethanthatinthelinearmodelaswell.Additionally,moredistinctcouplingeffectsareobservedintheproposednonlinearmodelthanthoseinthelinearmodel.Finally,itshowsthattheaerodynamicloads,thestructuralloadsandglobaldynamicresponsesoffloatingoffshorewindturbinesusingthenonlineardynamicmodelareslightlysmallerthanthoseusingthelineardynamicmodel.Insummary,comparedwiththeconventionallineardynamicmodel,theproposednonlinearcouplingdynamicmodelisahigher-orderdynamicmodelinconsiderationoftherigid-flexiblecouplingeffectsoffloatingoffshorewindturbines,andaccordmoreperfectlywiththeengineeringfacts.

简介：Thispaperinvestigatesasimplifiedmethodtodeterminetheoptimalstiffnessofflexibleconnectorsonamobileoffshorebase(MOB)duringthepreliminarydesignstage.Athree-modulenumericalmodelofanMOBwasusedasacasestudy.Numerousconstraintforcesandrelativedisplacementsfortheconnectorsatroughseastateswithdifferentwaveangleswereutilizedtodeterminetheoptimizedstiffnessoftheflexibleconnectors.Therangeofoptimalstiffnessesfortheconnectorswasobtainedbasedonthecombinationandintersectionoftheoptimizedstiffnessresults,andtheimplementationstepswereelaboratedindetail.Thepercentagereductionsoftheoptimizedandoptimalstiffnessoftheflexibleconnectorweredeterminedtoquantitativelyevaluatethedecreasesoftheconstraintforceandrelativedisplacementoftheconnectorscomparedwiththosecalculatedbyusingtheoriginalrangeoftheconnectorstiffnesses.Theresultsindicatetheaccuracyandfeasibilityofthismethodfordeterminingtheoptimalstiffnessoftheflexibleconnectorsanddemonstratetherationalityandpracticabilityoftheoptimalstiffnessresults.Theresearchideas,calculationprocess,andsolutionsfortheoptimalstiffnessoftheflexibleconnectorsofanMOBinthispapercanprovidevaluabletechnicalsupportforthedesignoftheconnectorsinsimilarsemisubmersiblefloatingstructures.

简介：在这篇论文大，偏转Euler横梁的动态问题reinvestigated。颤动控制方程被导出基于多身体系统方法。为解决结果的Anumerical过程微分代数学的方程根据与Newton-Raphson反复的方法相结合的Newmark直接集成方法被介绍。潜水艇横梁在对流传热的坐标系统被当作小变丑，它能极大地简化变丑描述。潜水艇横梁的僵硬运动通过对流传热的坐标系统的运动被考虑。数字例子被执行，在结果显示出建议方法的有效性的地方。

简介：Anumericalstudybasedonawakeoscillatormodelwasconductedtodeterminetheresponseperformanceofvortex-inducedvibration(VIV)onalongflexiblecylinderwithpinned-pinnedboundaryconditionssubjectedtolinearandexponentialshearflows.Thecouplingequationsofastructuralvibrationmodelandwakeoscillatormodelweresolvedusingastandardcentralfinitedifferencemethodofthesecondorder.TheVIVresponsecharacteristicsincludingthestructuraldisplacement,structuralfrequency,structuralwavenumber,standingwavebehavior,travellingwavebehavior,structuralvelocity,liftforcecoefficientandtransferredenergyfromthefluidtothestructurewithdifferentflowprofileswerecompared.ThenumericalresultsshowthattheVIVdisplacementisacombinationofstandingwavesandtravellingwaves.Forlinearshearflow,standingwavesandtravellingwavesdominatetheVIVresponsewithinthelow-velocityandhigh-velocityzones,respectively.Thenegativevaluesofthetransferredenergyonlyoccurwithinthelow-velocityzone.However,forexponentialshearflow,travellingwavesdominatetheVIVresponseandthenegativeenergyoccursalongtheentirelengthofthecylinder.

简介：Combinedmulti-bodydynamicswithstructuraldynamics,anewdiscreteelementwithflexibleconnector,whichisapplicablefor3-Dbeamstructures,isdevelopedinthispaper.Boththegeneralizedelasticcoefficientmatrixoftheflexibleconnectorandthemassmatrixofdiscreteelementmaybeoff-diag-onalinageneralcase.Thezero-lengthrigidelementisintroducedtosimulatethenodeatwhichmultipleel-ementsarejointedtogether.Itmayalsobeeffectivewhentheaxesofadjacentelementsarenotinthesameline.Theexamplesforeigenvaluecalculationshowthatthemodelissuccessful.Itcanbeextendedtothegeometricnonlinearresponseanalysis.

简介：Inthiswork,westudythecoupledcross-flowandin-linevortex-inducedvibration(VIV)ofafixedlymountedflexiblepipe,whichisfreetomoveincross-flow(Y-)andin-line(X-)directioninafluidflowwherethemassandnaturalfrequenciesarepreciselythesameinbothX-andY-direction.Thefluidspeedvariesfromlowtohighwiththecorrespondingvortexsheddingfrequencyvaryingfrombelowthefirstnaturalfrequencytoabovethesecondnaturalfrequencyoftheflexiblepipe.Particularemphasiswasplacedontheinvestigationoftherelationshipbetweenin-lineandcross-flowvibration.Theexperimentalresultsanalyzedbyusingthesemeasurementsexhibitsseveralvaluablefeatures.

简介：Anexperimentalstudyonabareflexiblecylinderaswellascylindersfittedwithtwotypesofcross-sectionedhelicalstrakeswascarriedoutinatowingtank.Themainpurposeofthispaperistoinvestigatetheeffectsofstrakes'crosssectiononthevortex-inducedvibrations(VIV)suppressionofaflexiblecylinder.Thesquare-sectionedandroundsectionedhelicalstrakeswereselectedintheexperimentaltests.Theuniformcurrentwasgeneratedbytowingthecylindermodelsalongthetankusingatowingcarriage.TheReynoldsnumberwasintherangeof800–16000.Thestrainresponsesweremeasuredbythestraingagesincross-flow(CF)andin-line(IL)directions.Amodalanalysismethodwasadoptedtoobtainthedisplacementresponsesusingthestrainsignalsindifferentmeasurementpositions.Thecomparisonoftheexperimentalresultsamongthebarecylinder,square-sectionedstrakedcylinderandroundsectionedstrakedcylinderwasperformed.Thehelicalstrakescaneffectivelyreducethestrainamplitude,displacementamplitude,responsefrequenciesanddominantmodesofaflexiblecylinderexcitedbyVIV.Andthemeandragcoefficientsofstrakedcylinderswereapproximatelyconsistentwitheachother.Inaddition,thesquaresectionedandround-sectionedstrakesnearlysharethesimilarVIVreductionbehaviors.Sometimes,thestrakeswithround-sectionrepresentmoreexcellenteffectsontheVIVsuppressionofresponsefrequencythanthosewithsquaresection.

简介：Thevibrationresponseofafree-hangingflexibleriserinducedbyinternalgas-liquidslugflowwasstudiedexperimentallyinasmall-diametertubemodelbasedonFroudenumbercriterion.Theflowregimeinacurvedrisermodelandtheresponsedisplacementsoftheriserweresimultaneouslyrecordedbyhighspeedcameras.Thegassuperficialvelocityrangesfrom0.1m/sto0.6m/swhiletheliquidsuperficialvelocityfrom0.06m/sto0.3m/s.Severesluggingtype3,unstableoscillationflowandrelativelystableslugflowwereobservedintheconsideredflowrates.Severesluggingtype3characterizedbyprematuregaspenetrationoccursatrelativelylowflowrates.Boththecycletimeandsluglengthbecomeshorterasthegasflowrateincreases.Thepressureattheriserbaseundergoesalongerperiodandlargeramplitudeoffluctuationascomparedwiththeothertwoflowregimes.Additionally,severesluggingleadstothemostvigorousin-planevibration.However,theresponsesintheverticalandhorizontaldirectionsarenotsynchronized.Theverticalvibrationisdominatedbythesecondmodewhilethehorizontalvibrationisdominatedbythefirstmode.Similartothevortex-inducedvibration,threebranchesareidentifiedasinitialbranch,build-upbranchanddescendingbranchfortheresponseversusthemixturevelocityofgas-liquidflow.

简介：基于历史的跑，核心之一联合模型Intercomparison工程(CMIP5)的第五个阶段试验，雪深度(SD)和灵活全球Ocean-Atmosphere-Land系统(FGOALS)的二个版本模仿的雪盖子部分(SCF)当模特儿，格子点版本2(g2)并且光谱版本2(s2)，对观察数据被验证。结果表明在北半球(NH)上的SD和SCF的空间模式被两个模型模仿很好，除了在西藏的高原上，与在分别地为SD和SCF在0.7和0.8附近的所有月的平均空间关联系数。尽管雪累积的发作被二个模型以SD和SCF的年度周期捕获很好，g2在NH的很中间纬度、高纬度的区域上过高估计SD/SCF。因为它在它的大气的部件考虑喷雾器的间接效果，分析证明g2比s2生产更低的温度，它是为二个模型之间的SD/SCF差别的主要司机。另外，两个模型模仿SCF的重要减少趋势很好在上(在在大西洋和108坏訄?訄的和平的盆北方的欧亚大陆和温暖的SST上的30air吗？？