简介：Thechaotictransientsofacurvedfluidconveyingtubesubjectedtoanonlinearfoundationareinvestigated.TheassumptionoftheinextensibilityofthetubeisappliedtoderivethenonlineardifferentialequationofmotionviatheNewtonianapproach,withthedifferentialquadraturemethodusedtodiscretizethecurvedtubemodelinthespatialdomain.Andthenonlineardynamicmotionequationisobtained.Thenumericalanalysisshowsthat,thefinalsteadystatesaresensitivetotheinitialsystemconditionsinalargeparameterregionofthefluidspeed.Thisphenomenonofchaotictransientsisinfrequentforfluidconveyingtubes.

简介：基于连续统的有限变丑理论和poroelastic理论，为在自然、起始的坐标的浸透液体的多孔的媒介(FSPM)的acoustoelastic理论被开发在波浪速度上调查有效压力和液体毛孔压力的影响。第一，在FSPM的大部分静态的变丑前上附加的一个小动态运动的假设产出自然、起始、最后的配置，谁的排水量，紧张，和压力稳固骨骼并且在一个FSPM粒子的液体能分别地在自然、起始的坐标被描述。第二，从运动和FSPM的非线性的组成的关系的介绍的最后状态的方程的平衡的起始状态的方程的减法为小动态运动导致运动的方程。第三，同类的变丑前的考虑和小动态运动的飞机泛音形式给一个acoustoelastic方程，它为快纵的波浪的关系提供分析明确的表达，快砍波浪，慢砍波浪，并且有稳固骨骼的压力和液体毛孔压力的慢纵的波浪。最后，在靠近毛孔的jacketed条件，开毛孔的jacketed条件，传统的unjacketed条件，和triaxial状况下面的各向同性的FSPM作为一个例子被拿讨论速度快并且慢砍沿着起始的主要稳固骨骼的紧张之一的方向宣传的波浪。详细讨论证明FSPM的波浪速度被有效压力和液体毛孔压力通常影响。仅仅，液体毛孔压力在FSPM的波浪速度上有小效果应用起始的主管的部件稳固骨骼强调或紧张是相等的，它与以前的试验性的结果一致。

简介：Absorptionofacousticnanowaveinspecificfrequencyregionisimportantforthedesignofacousticfilter.Thispaperputsforwardametamaterialmodelmadeupoffluid-conveyingcarbonnanotubes(CNT),whichcanabsorbacousticnanowaveinagivenfrequencyrangebyadjustingthelengthsandfluidvelocitiesofthemselves.Absorptioncoefficientsarecalculatedoutthroughthecombinationofthefiniteelementmethodwiththetheoreticalmodel,whichare0.4~0.55relatingtodifferentfluidvelocitiesforthecrossing-distributedmodel.Comparisonsaremadebetweenthecrossedmodelandthealignedone,whichprovethattheCNTforestwithcrosseddistributionismoreeffectiveinacousticwaveabsorption.

简介：Thenaturalfrequencies,complexmodesandcriticalspeedsofanaxiallymovingrectangularplate,whichispartiallyimmersedinafluidandsubjectedtoapretension,areinvestigated.Theeffectsoffreesurfacewaves,compressibilityandviscidityofthefluidareneglectedintheanalysis.Thesubsectionfunctionsareusedtodescribethediscontinuouscharacteristicsofthesystemduetopartialimmersion.Theclassicalthinplatetheoryisadoptedtoformulatetheequationsofmotionofavibratingplate.ThevelocitypotentialandBernoulli’sequationareusedtodescribethefluidpressureactingonthemovingplate.Theeffectoffluidonthevibrationsoftheplatemaybeequivalenttotheaddedmassontheplate.Theeffectsofdistanceratio,movingspeed,immersed-depthratio,boundaryconditions,stiffnessratioandaspectratiooftheplateaswellasthefluid-platedensityratiosonthefreevibrationsofthemovingplate-fluidsystemareinvestigated.

简介：Anumericalmethodforsimulatingnonlinearfluid-rigidstructureinteractionproblemsisdeveloped.Thestructureisassumedtoundergolargerigidbodymotionsandthefluidflowisgovernedbynonlinear,viscousornon-viscous,fieldequationswithnonlinearboundaryconditionsappliedtothefreesurfaceandfluid-solidinteractioninterfaces.AnArbitrary-Lagrangian-Eulerian(ALE)meshsystemisusedtoconstructthenumericalmodel.Amulti-blocknumericalschemeofstudyisadoptedallowingfortherelativemotionbetweenmovingoversetgrids,whichareindependentofoneanother.Thisprovidesaconvenientmethodtoovercomethedifficultiesinmatchingfluidmesheswithlargesolidmotions.Nonlinearnumericalequationsdescribingnonlinearfluid-solidinteractiondynamicsarederivedthroughanumericaldiscretizationschemeofstudy.Acouplingiterationprocessisusedtosolvethesenumericalequations.Numericalexamplesarepresentedtodemonstrateapplicationsofthemodeldeveloped.

简介：Thevibrationalfrequencyanalysisoffiniteelastictubefilledwithcompressibleviscousfluidhasreceivedplentyofattentioninrecentyears.Toapplyfrequencyanalysistodefectdetectionforexample,itisnecessarytoinvestigatethevibrationalbehaviorunderappropriateboundaryconditions.Inthispaper,wepresentadetailedtheoreticalstudyofthethreedimensionalmodalanalysisofcompressiblefluidwithinanelasticcylinder.Thedispersionequationsofflexural,torsionalandlongitudinalmodesarederivedbyelastodynamictheoryandtheunsteadyStokesequation.ThesymbolicsoftwareMathematicaisusedinordertofindthecoupledvibrationfrequencies.Thedispersionequationisdeducedandanalyticallysolved.Thefiniteelementresultsarecomparedwiththepresentmethodforvalidationandanacceptablematchbetweenthemareobtained.

简介：基于Fl銈賦蒚雨馢髧蚜?蒚?蒚??鋥??吗？

简介：处于在边界随机刺激下面的飞机紧张状态的压电的厚壳的随机的反应与压电的圆柱的壳被学习并且说明。为电的潜力的微分方程放射状地是综合的作为排水量的功能获得电的潜力。随机的压力边界条件被转变变换成同类的，它在随机的刺激下面为排水量产出电、机械的联合微分方程。然后，这个部分微分方程用Galerkin方法和Legendre多项式被变换成平常的微分方程，它与不对称的僵硬矩阵代表一个随机的multi-degree-of-freedom系统由于电、机械联合并且转变边界条件。频率反应功能矩阵和反应力量光谱系统的密度矩阵基于随机的颤动的理论被导出。吝啬平方的排水量和压电的壳的电的潜力最后被获得，并且频率反应特征和电、机械的联合性质被探索。

简介：Aboundaryelementmethodispresentedforthecoupledmotionanalysisofstructuralvibrationwithsmall-amplitudefluidsloshingintwo-dimensionalspace.ThelinearizedNavier-Stokesequationsareconsideredinfrequencydomainandtransformedintoboundaryintegralequations.AnappropriatefundamentalsolutionfortheHelmholtzequationwithpureimaginaryconstantisfound.Theconditionofzero-stressisimposedonthefreesurface,andnon-slipconditionoffluidparticlesisimposedonthewallsofthecontainer.Forrigidmotionmodels,theexpressionsforaddedmassandaddeddampingtothestructuralmotionequationsareobtained.Sometypicalnumericalexamplesarepresented.

简介：Basedonthetheoryofporousmedia,ageneralGurtinvariationalprinciplefortheinitialboundaryvalueproblemofdynamicalresponseoffluid-saturatedelasticporousmediaisdevelopedbyassuminginfinitesimaldeformationandincompressibleconstituentsofthesolidandfluidphase.Thefiniteelementformulationbasedonthisvariationalprincipleisalsoderived.Asthefunctionalofthevariationalprincipleisaspatialintegraloftheconvolutionformulation,thegeneralfiniteelementdiscretizationinspaceresultsinsymmetricaldifferential-integralequationsinthetimedomain.Insomesituations,thedifferential-integralequationscanbereducedtosym-metricaldifferentialequationsand,asanumericalexample,itisemployedtoanalyzethereflectionofone-dimensionallongitudinalwaveinafluid-saturatedporoussolid.Thenumericalresultscanprovidefurtherunderstandingofthewavepropagationinporousmedia.

简介：Vibrationcharacteristicsoffluid-filledmulti-walledcarbonnanotubesarestudiedbyusingnonlocalelasticFlu¨ggeshellmodel.VibrationgoverningequationsofanN-layercarbonnanotubeareformulatedbyconsideringthescaleeffect.Inthenumericalsimulations,theeffectsofdifferenttheories,small-scale,variationofwavenumber,theinnermostradiusandlengthofdoublewalledandtriple-walledcarbonnanotubesareconsidered.Vibrationalfrequenciesdecreasewithanincreaseofscalecoefficient,theinnermostradius,lengthofnanotubeandeffectsofwallnumberarenegligible.Theresultsshowthatthecut-offfrequenciescanbeinfluencedbythewallnumberofnanotubes.

简介：TheDonnelltheoryofshellisappliedtodescribeshellmotionandlayermotionisdescribedbymeansofthree-dimensionalNavierequations.Usingdeformationharmoniousconditionsoftheinterface,theeffectsofstiffenersandlayeraretreatedasreverseforcesandmomentsactingonthecylindricalshell.Instudyingtheacousticfieldproducedbyvibrationofthesubmergedring-stiffenedcylindricalcoatedshell,thestructuredynamicequation,Helmholtzequationinthefluidfieldandthecontinuousconditionsofthefluid-structureinterfacecomposethecou-plingvibrationequationofthesound-fluid-structure.Theextractofsoundpressurecomesdowntotheextractofcouplingvibrationequation.Byuseofthesolutionoftheequation,theinfluencesofhydrostaticpressure,physicalcharactersandgeometricparametersofthelayeronsoundradiationarediscussed.

简介：Thenonlinearbehaviorofacantileveredfluidconveyingpipesubjectedtoprincipalparametricandinternalresonancesisinvestigatedinthispaper.Theflowvelocityisdividedintoconstantandsinusoidaiparts.Thevelocityvalueoftheconstantpartissoadjustedsuchthatthesystemexhibits3:1internalresonancesforthefirsttwomodes.Themethodofmultiplescalesisemployedtoobtaintheresponseofthesystemandasetoffourfirst-ordernonlinearordinary-differentialequationsforgoverningtheamplitudeoftheresponse.TheeigenvaluesoftheJacobianmatrixareusedtoassessthestabilityoftheequilibriumsolutionswithvaryingparameters.Thecodimension2derivedfromthedouble-zeroeigenvaiuesisanalyzedindetail.Theresultsshowthattheresponseamplitudemayundergosaddle-node,pitchfork,Hopf,homoclinicloopandperiod-doublingbifurcationsdependingonthefrequencyandamplitudeofthesinusoidalflow.Whenthefrequencyofthesinusoidalflowequalsexactlyhalfofthefirst-modefrequency,thesystemhasaroutetochaosbyperiod-doublingbifurcationandthenreturnstoaperiodicmotionastheamplitudeofthesinusoidalflowincreases.