简介：Theturtleshellisanamazingstructureoptimizedthroughthelong-termevolutionbynature.Thispaperreportstheexperimentalstudyonthemechanicalpropertyatdifferentlevelsandlocations,andthemicrostructureoftheshellfromTrachemysscripta(Red-earturtle)livinginSouthChina.

简介：大飞机具有轻质大柔性特点,使得气动/结构耦合作用增强,在设计过程中需要考虑这种耦合效应,直接调用CSD/CFD方法计算周期长,无法满足工程需要.代理模型方法由于能显著提高工程优化设计的效率,已广泛应用于飞行器气动外形优化设计中.采用Kriging方法建立代理模型,通过求解EI函数最大值得到需添加的样本点以更新代理模型,提高代理模型的拟合精度,结合改进的粒子群最优化方法对大飞机的结构刚度进行了优化设计.结果表明,该优化方法能够处理复杂目标的全局优化问题,在保证升力系数及纵向稳定性能不恶化的前提下,降低飞机巡航状态的飞行阻力.

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简介：WiththeincorporationoftotalLagrangiansmoothedparticlehydrodynamics（SPH）methodequationandmovingleastsquare（MLS）function,thetraditionalSPHmethodisimprovedregardingthestabilityandconsistency.BasedonMindlin-Ressinerplatetheory,theSPHmethodsimulatingdynamicbehaviorviaonelayerofparticlesisappliedtoplate＇smid-plane,i.e.,aSPHshellmodelisconstructed.Finally,throughcomparativeanalysesonthedynamicresponseofsquare,stiffenedshellsandcylindricalshellsundervariousstrongimpactloadswithcommonfiniteelementsoftware,thefeasibility,validityandnumericalaccuracyoftheSPHshellmethodareverified.Consequently,furtherresearchesonSPHshellmaywellpavethewaytowardssolvingproblemsinvolvingdynamicplasticdamage,tearingorevencrushing.

简介：Thispapergivesanexactanalysisofarotatingpiezoelectricsphericalshellwitharbitrarythickness.Atfirst,threedisplacementfunctionsareintroducedtosimplifythebasicequationsofasphericallyisotropic,piezoelectricmedium.Byexpandingthedisplacementfunctionsaswellastheelectricpotentialintermsofsphericalharmonics,thebasicequationsofequilibriumareconvertedtoanuncoupledEulertype,secondorderordinarydifferentialequationandacoupledsystemofthreesecondorderordinarydifferentialequations.Ageneralsolutiontothehomogeneousequationsofequilibriumisthenderived.Thestaticanalysisofarotatingsphericalshellisthenperformedandnumericalexampleispresented.

简介：Inthispaper,aboundaryelementschemeforarbitraryelasticthinshellsiselaborated,BasedonBEMof3DlinearelasticityandKirchhoff’shypothesis,boundaryintegralequationsforshellsarededuced.Asaresult,onlyKelvin’ssolutionisused,thedifficulty,infindingafundamentalsolutionofarbitraryshellsissuccessfullyavoided.

简介：Coreshell硅石nanoparticles在修改弄湿行为的表面是优异的，提高在结晶化的成核和生长，改进裸体nanoparticles的分散，并且因此升级器官的聚合物的全面性质。在包括聚酯的几聚合物的monodispersecoreshell硅石粒子的分散行为和形态学被考察，他们的潜在的应用程序被讨论。

简介：Withrespecttoanarbitraryconfigurationofadeformedstructure,twosetsofincrementalequationsareproposedforthedeformationanalysisofrevolutionshellsanddiaphragmsloadedbybothlateralpressuresandtheinitialstressesproducedinmanufacturing.ThesegeneralequationscanbereducedtothesimplifiedKoiter'sReissner-Meissner-Reissner(RMR)equationsandthesimplifiedReissner'sequations,whentheinitialstressesaresettozero.TheycanalsobededucedtothetotalLagrangeformortheupdatedLagrangeform,respectively,asthestructureisspecifiedastheun-deformedortheformer-deformedconfigurations.Theseincrementalequationscanbeeasilytransformedintofinitedifferenceformsandsolvedbycommonnumericalsolversofordinarydifferentialequations.Somenumericalexamplesarepresentedtoshowtheapplicationsoftheincrementalequationstothedeepshellofrevolutionandthecorrugateddiaphragmsusedinmicroelectronicalmechanicalsystem(MEMS).Theresultsareingoodagreementwiththosefromfiniteelementmethod(FEM).

简介：Thenonlineardynamicalequationsofaxlesymmetryareestablishedbythemethodofquasi-shellsforthree-dimensionalshallowconicalsingle-layerlatticeshells.Thecompatibleequationsaregiveningeometricalnonlinearrange.AnonlineardifferentialequationcontainingthesecondandthethirdordernonlinearitemsisderivedundertheboundaryconditionsoffixedandclampededgesbythemethodofGalerkin.TheproblemofbifurcationisdiscussedbysolvingtheFloquetexponent.Inordertostudychaoticmotion,theequationsoffreeoscillationofakindofnonlineardynamicssystemaresolved.Thenanexactsolutiontononlinearfreeoscillationoftheshallowconicalsingle-layerlatticeshellisfoundaswell.ThecriticalconditionsofchaoticmotionareobtainedbysolvingMelnikovfunctions,somephaseplanesaredrawnbyusingdigitalsimulationprovingtheexistenceofchaoticmotion.

简介：ＮＯＮ－ＳＹＭＭＥＴＲＩＣＡＬＬＡＲＧＥＤＥＦＯＲＭＡＴＩＯＮＯＦＡＳＨＡＬＬＯＷＴＨＩＮＳＰＨＥＲＩＣＡＬＳＨＥＬＬＷａｎｇＸｉｎｚｈｉ（王新志）ＲｅｎＤｏｎｇｙｕｎ（任冬云）ＷａｎｇＬｉｎｘｉａｎｇ（王林祥）ＹｅｈＫａｉｙｕａｎ（叶开沅）（Ｇａｎ...

简介：Thispaperisconcernedwithanumericalsolutionofhyperboliccoolingtowershell,aclassoffullnonlinearproblemsinsolidmechanicsofconsiderableinterestinengineeringapplications.Inthisanalysis,thepost-bucklinganalysisofcoolingtowershellwithdiscretefixedsupportandundertheactionofwindloadsanddeadloadisstudied.Theinfluencesofring-stiffeneroninstabilityloadarealsodiscussed.Inaddition,anewsolutionprocedurefornonlinearproblemswhichisthecombinationofloadincrementiterationwithmodifiedR-Care-lengthmethodissuggested.Finally,someconclusionshavingimportantsignificanceforpracticeengineeringaregiven.

简介：Theshallowcylindricalstructureissuitabletodevelopbroadbandvibrationenergyharvestersduetothepropertyoftheinherentmechanicalbistability.Inthisletter,theoptimumdesignofthebistablecylindricalshellforbroadbandenergyharvestingapplicationisinvestigatedfromthestructuralpointofview.Theoutputpowerisevaluatedbytheconceptoftheharvestablepower,whichbalancesthefrequencyofsnapthroughandthereferredoutputenergyassociatedwitheachsnapthrough.Thenondimensionalharvestablepowerisanalyticallyexpressedasthefunctionofthenon-dimensionalcurvatureparameterandoneconstructedparameter.Theuniversaldependenceoftheoptimalcurvatureparameterandtheassociatedoptimalharvestablepowerontheconstructedparameterisderived,whichcanbewellapproximatedbythelinearrelationindoublelogarithmiccoordinate.

简介：Aniterationmethodofstatisticlinearization(IMSL)ispresented.Bythismethod,anequivalentlineartermwasformedingeometricrelationandthenanequivalentstiffnessmatrixfornonlinearterminvibrationequationwasestablished.Usingthemethodtosolvethestatisticlinearvibrationequations,theeffectofgeometricnonlinearityontherandomresponseofrotationalshellisobtained.

简介：Basedonthefundamentaldynamicequationsoffunctionallygradedmaterial(FGM)cylindricalshell,thispaperinvestigatesthesoundradiationofvibrationalFGMshellinwaterbymobilitymethod.ThismodeltakesintoaccounttheexteriorfluidloadingduetothesoundpressradiatedbytheFGMshell.TheFGMcylindricalshellwasexcitedbyaharmoniclineradialforceuniformlydistributingalongthegenerator.TheFGMshellequationsofmotion,theHelmholtzequationintheexteriorfluidmediumandth...

简介：ＮＯＮ－ＬＩＮＥＡＲＥＬＡＳＴＩＣＴＨＥＯＲＹＯＦＲＥＣＴＡＮＧＵＬＡＲＲＥＴＩＣＵＬＡＴＥＤＳＨＡＬＬＯＷＳＨＥＬＬＳＴＲＵＣＴＵＲＥＳＮｉｅＧｕｏ－ｈｕａ（聂国华）（ＤｅｐａｒｔｍｅｎｔｏｆＥｎｇｉｎｅｅｒｉｎｇＭｅｃｈａｎｉｃｓ，ＴｏｎｇｊｉＵ...

简介：Basedonthetheoryforsmallfieldssuperposedonrelativelylargerfieldsinanelectroelasticbody,&theoreticalanalysisisperformedonacircularplatethickness-shearcrystalresonatorsealedinacircularcylindricalshellforpressuremeasurement.Asimpleexpressionisobtainedforpressureinducedfrequencyshiftsintheresonator,whichisexaminedfordesignoptimization.Numericalresultsshowthatthefrequencyshiftsdependlinearlyonthepressure,andthatapressuresensorwithasofteroutershellorasmallerthicknessratioofthecrystalplatetotheoutershellhashighersensitivity.

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简介：InthisworkweproposetoreplacetheGLPDhypo-elasticitylawbyamorerigorousgeneralizedHooke’slawbasedonclassicalmaterialsymmetrycharacterizationassumptions.ThislawintroducesinadditiontothetwowellknownLame’smoduli,fiveconstitutiveconstants.AnanalyticalsolutionisderivedfortheproblemofasphericalshellsubjectedtoaxisymmetricloadingconditionstoillustratethepotentialoftheproposedgeneralizedHooke’slaw.

简介：Thispapergeneralizesthesingle-shellKidder'sself-similarsolutiontothedouble-shellonewithadiscontinuityindensityacrosstheinterface.AnisentropicimplosionmodelisconstructedtostudytheRayleigh-Taylorinstabilityfortheimplosioncompression,AGodunov-typemethodintheLagrangiancoordinatesisusedtocomputetheone-dimensionalEulerequationwiththeinitialandboundaryconditionsforthedouble-shellKidder'sself-similarsolutioninsphericalgeometry.Numericalresultsareobtainedtovalidatethedouble-shellimplosionmodel.Byprogrammingandusingthelinearperturbationcodes,alinearstabilityanalysisontheRayleigh-Taylorinstabilityforthedouble-shellisentropicimplosionmodelisperformed.Itisfoundthat,whentheinitialperturbationisconcentratedmuchclosertotheinterfaceofthetwoshells,orwhenthesphericalwavenumberbecomesmuchsmaller,themodalradiusoftheinterfacegrowsmuchfaster,i.e.,moreunstable.Inaddition,fromthespatialpointofviewforthecompressibilityeffectontheperturbationevolution,thecompressibilityoftheoutershellhasadestabilizationeffectontheRayleigh-Taylorinstability,whilethecompressibilityoftheinnershellhasastabilizationeffect.