学科分类
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18 个结果
  • 简介:Inthispaper,wegivethedistributionoftemperaturefie1dandpulsephotoacousticpressuregener-atedbypulsedlaserinliquid.Theeffectofpulsedurationandlaserbeamdimensiononthepres-suresignalisdiscussed.TheexperimentalresultsobtainedbytheGausslaserbeamdeflectiontech-niqueagreewiththetheoryqualitatively.Thistechniqueprovidesanovelopticalmethodforthecontactlessandrapidmeasurementofthermodynamicparameters.

  • 标签: DEFLECTION pulsed excitation LASER PROBING THERMODYNAMIC
  • 简介:Fordecades,nacrehasinspiredresearchersbecauseofitssophisticatedhierarchicalstructureandremarkablemechanicalproperties,especiallyitsextremefracturetoughnesscomparedwiththatofitspredominantconstituent,CaCO3,intheformofaragonite.Crackdeflectionhasbeenextensivelyreportedandregardedastheprincipaltougheningmechanismfornacre.Inthispaper,ourattentionisfocusedoncrackevolutioninnacreunderaquasi-staticstate.Weusethenotchedthree-pointbendingtestofdehydratednacreinsituinascanningelectronmicroscope(SEM)tomonitortheevolutionofdamagemechanismsaheadofthecracktip.Theobservationsshowthatthecrackdeflectionactuallyoccursbyconstrainedmicrocracking.Onthebasisofourfindings,acrackpropagationmodelisproposed,whichwillcontributetouncoveringtheunderlyingmechanismsofnacre’sfracturetoughnessanditsdamageevolution.Theseinvestigationswouldbeofgreatvaluetothedesignandsynthesisofnovelbiomimeticmaterials.

  • 标签: Biological mineralized material NACRE TOUGHENING mechanism
  • 简介:Anembeddedcylinderisalarge-diametercylinderembeddedinasoilfoundation.Thestateoffailureofsuchanembeddedcylindricalstructureshowslargedeflectioninsteadofslideandoverturnofthetraditionalgravitytypeofstructureplacedonarubblebaseorfoundationbase.Thecriticalvalueofdeflectionoftheembeddedcylindricalstructure,whichisthemaximumallowabledeflectionforstabilitycalculationofthecylinder,isavitalcontrolvalue.Throughinvestigationondeflectionandsoilpressuresonanembeddedcylinderbymodelexperiments,thevariationsoftheangleofrotationθofacylinderwitheffectiveanti-overturningratioηandmomentMHofthrustarediscussed.Onthebasisofexperimentalstudy,thecriticalvalueofdeflectionofthecylindricalstructureisproposedinthepaper.Meanwhile,theformulasforcalculatingdeflectionofcylindersarederived.

  • 标签: 动态波压 垂直深埋大型圆柱结构 单柱形结构 连续柱形结构 频域 波浪谱
  • 简介:为散布17208Pb被测量了。ln(dσ/dθ)对θ2的尖分散阴谋从散布微分生气的节的橡皮的尖分发被获得。为可得到的试验性的数据的尖分散上的系统的分析显示在在放牧角度以内的向前尖的范围有一个尖分散拐弯处角度。这个转弯的角度能在古典偏转功能作为原子彩虹被澄清。原子彩虹角度的异国情调的行为提供一根新探针调查光圈和皮肤现象。

  • 标签: 色散 偏转函数 重离子 弹性散射
  • 简介:动态反应上的学习,和特别使硬的盘子的非线性的动态反应由他们的断绝和不同类是复杂的。有限元素方法(女性)并且有限长带方法通常在他们的分析被采用。尽管许多有用结论被获得了,计算费用是庞大的。基于一些假设,有大偏转的夹钳的使硬的盘子的动态塑料反应被一个单身地对称的横梁模型理论上此处调查。第一,塑料绳必须满足的偏转条件被线性化的时刻轴的力量相互作用曲线为单身地对称的生气的节和联系塑料流动规则获得。第二,在不同负担紧张下面的横梁的可能的运动机制详细被分析。为有塑料变丑的结构,一个简化方法然后被给任意的影响负担能被矩形的脉搏相等地代替。最后,证实建议方法的有效性,有四个充分夹钳的边的一个单程的使硬的盘子的动态塑料反应被计算。理论结果在对那些的好同意女性。它显示现在的计算模型安逸、可行,并且负担的相等的替换几乎没在最后的偏转上有影响。

  • 标签: 动态塑性响应 变硬板块 大挠度 对称相交断面
  • 简介:一个向轴的方向的大偏转有一张矩形的剖面图的可扩展的弄弯的横梁被调查。有弹性的横梁被假定满足Euler-Bernoulli假定并且用Ludwick类型材料做的。通过相当简化的集成,横梁的轴的紧张和弯曲在含蓄的明确的表达被介绍。包含的管理方程几何并且弄弯的横梁的材料非线性被射击方法导出并且解决。当横梁的起始的弯曲是零时,弄弯的横梁被堕落进一根直横梁,并且现在的模型获得的预言的结果与在开的文学的那些一致。数字例子进一步为弄弯的伸臂被给并且简单地支持在延伸之间的横梁,和couplings并且弯曲被作出对有利的裁决弄弯的横梁。

  • 标签: 大偏转 弄弯的横梁 Ludwick 类型材料 非线性 O343.5 74B20
  • 简介:Thispapernumericallystudiestheinfluenceofthedownwardspoilerdeflectionontheboundarylayerflowofahigh-lifttwo-elementairfoilconsistingofadroopnose,amainwing,adownwarddeflectingspoilerandasingleslottedflap.Bothoftheboundarylayeroftheuppersurfaceofthespoilerandtheconfluentboundarylayeroftheuppersurfaceoftheflapbecomethicker,asthedownwardspoilerdeflectionincreases.Comparedtotheattachedflowattheangleofattackof10°,theflowoftheuppersurfaceofthespoilerbecomesseparatedattheangleofattackof16°whenthespoilerdeflectionislargeenough,whichcorrespondstotheboundarylayerflowreversalinvelocityprofiles.

  • 标签: 数值研究 扰流板 高升力 偏转 结构影响 边界层流动
  • 简介:Inthisinvestigation,attemptsaremadetoexaminetheeffectsofsoil-structureinteractiononthedeflectionmodificationfactorofmultistorybuildingsandtoclarifytheroleofdeformablesoilonthisfactor.Acomprehensivestudyisconductedtoinvestigatetheeffectofinertialinteractionondisplacementdemandratiosinsoil-structuresystemswithdifferentstructuralcharacteristicsandvariousnon-dimensionalparameters,usingasimplifiedinteractingmodel.Atwo-stepregressionanalysisofthenonlinear,dynamiccomputersimulationresultsobtained,leadstoareliableandaccurateformulaforpredictingdeflectionmodificationfactorsthatincorporatefoundationflexibility.Theresultsillustratethattheapplicationofdeflectionmodificationfactorsderivedfromfixed-basestructurescanleadtounsafeevaluationofthestructuresonsoftsoil.Theproposedformulaprovidesausefultoolfordesignengineerstoincorporatetheeffectofsoil-structureinteractionintotheevaluationofstructuraldeformations.

  • 标签: defl ection modifi CATION FACTOR MULTISTORY
  • 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。

  • 标签: 船体 柔性梁 大变形动力响应分析 多柔体系统法 非线性
  • 简介:ThesolutionandcomputationalaspectsonnonlineardeflectionofYongjiangRailwayBridgeinNingbowereinvestigated.Anapproximateiterationalgorithmonnonlineargoverningequationwaspresented,andtheobtainedresultsshowthat,ifaltitudedifferenceandspanoftheriverbanksaretakenas5metersand100meters,respectively,themaximumgradientinthemiddleofthebridgeexceeds5%,muchlargerthanmaximumallowancegradientinrailwaydesigncode.Therefore,anewsolutionschemefordecreasinggradientofthebridgeisputforward,thatis,thealtitudedifferencebetweentworiverbankscanbedecreasedtoabout1/10oftheinitialmagnitudebybuildingroadbedswith0.5%gradientandIkilometerlengthattworiverbanks.Asadirectresult,thedeflectiongradientoftherailwaybridgeismuchreducedandthevalueisbetween0.5%~0.6%.

  • 标签: large DEFLECTION ELASTIC MODULUS CANTILEVER beam
  • 简介:Basedonenergyequilibrium,anewprocedurecalledtheMembraneFactorMethodisdevel-opedtoanalyzethedynamicplasticresponseofplateswithdeflectionsintherangewherebothbendingmo-mentsandmembraneforcesareimportant.Thefinaldeflectionofasimply-supportedcircularrigid-plasticplateloadedbyauniformlydistributedimpulseisobtained.Incomparisonwithotherapproximatesolutions,thepresentresultsarefoundtobesimplerandinbetteragreementwiththecorrespondingexperimentalvaluesreoordedbyFlorence.

  • 标签: dynamic plastic response of PLATES LARGE
  • 简介:这份报纸成功地为nanobeams在非局部的有弹性的压力地理论处理了三个关键却俯看的问题:增加非局部的效果的存在导致的(i)在许多减少了nanostructural僵硬,然而并非一致地为所有,学习的盒子,即,增加的静态的偏转,减少的自然频率和减少的弄弯的负担,吗尽管根据非局部的弹性地,理论首先由Eringen建立了的物理直觉不那样告诉?(ii)nanoscale完成的吸引人的结论在在学习的许多作为模范的盒子中的答案是失踪的,例如,把有在它的尖端的点负担的伸臂nanobeam的偏转弄弯;并且(iii)另外的高顺序的边界的不存在为一个高顺序的管理调节微分方程。在nanomechanics和一条准确变化主要途径使用非局部的弹性领域理论,我们为nanobeams弯曲导出新平衡条件,管理微分方程的领域和边界条件。这些方程和条件包含在符号关于相反的必要高顺序的微分条款以前在非局部的nano结构的静电干扰和动力学学习。在高顺序的条款的差别关于这份报纸的结论导致nanoscale效果的反向的趋势。有效地,这份报纸报导新平衡条件,管理为nanobeams弯曲的微分方程和边界条件和真基本静态的回答。非局部的nanostructures的广泛地接受的平衡条件事实上不在平衡,这也被结束,但是他们能被使完美非局部的弯曲时刻应该到一有效非局部的弯曲时刻被代替。这些结论被证实,在一般意义,由在象种类坡度理论,修改夫妇压力模型和实验那样的nanostructural模型的另外的途径。关键词弯曲-有效非局部的弯曲时刻-nanobeam-nanomechanics-nanoscale-非局部的有弹性的应力-种类坡度汉语Librarary分类O3432000数学题目分类74A60由郭工程从香港特别行政区的研究资助委员会由资助支持了的我x交流了(没有。CityU117406)

  • 标签: 弹性应力场 纳米效应 平衡条件 静态弯曲 挠度方程 非局部
  • 简介:Westudythedynamicbehaviorofaquartzcrystalresonator(QCR)inthickness-shearvibrationswiththeuppersurfacecoveredbyanarrayofmicro-beams(MBs)underlargedeflection.ThroughtakingintoaccountthecontinuousconditionsofshearforceandbendingmomentattheinterfaceofMBs/resonator,dependencesoffrequencyshiftofthecompoundQCRsystemversusmaterialparameterandgeometricalparameterareillustratedindetailfornonlinearandlinearvibrations.Itisfoundthatthefrequencyshiftproducesalittleright(left)translationforincreasingelasticmodulus(length/radiusratio)ofMBs.Moreover,thefrequencyright(left)translationdistancecausedbynonlineardeformationbecomesmoreseriousinthesecond-ordermodethaninthefirst-orderone.

  • 标签: 石英晶体谐振器 共振频率 厚度剪切 大挠度 模态 微梁
  • 简介:Thispaperfollowstheworkof[1,2].Therearesomeprogressindealingwithmoderatelysmallrotations(thesquaresofrotationanglesaretheorderofmagnitudeofstrains)ofmiddlesurfacenormalsofinsideandoutsideringshellsandcompressedangleofbellows.Calculationresultsagreewithexperimentswell.Tobellowdesign,themethodgiveninthispaperisofpracticalvalueandthediscussionoftheinfluenceofcompressedangleoncharacteristicrelationishelpful.

  • 标签: U-SHAPED BELLOWS LARGE axisymmetrical DEFLECTION compressed