简介:Thedynamicresponseofthenon-linearelasticsimplysupportedbeamsubjectedtoaxialforcesandtransverseperiodicloadisstudied.Melnikovmethodisusedtoconsiderthedynamicbehav-iorofthesystemwhosepost-bucklingpathissteady.Theeffectofthehigherordertermsinthecon-trollingequationistakenintoaccount.Itisfoundthatthefifth-ordertermshaveagreatinfluenceonthedynamicbehaviorofthesystem.Theresultshowsthatthereexisteitherhomoclinicorbitsorhete-roclinicorbitsinthesystem.Inthispaper,thecriticalvaluesofthesystementeringchaoticstatesaregiven.Thediagramofanexampleisshown.
简介:Theinterfacialbehaviorofpipejointsisstudiedinthispaper.Firstly,throughnonlinearfracturemechanics,theanalyticalexpressionsofinterfacialshearstressandtheloaddisplacementrelationshipatloadedendofpipejointsundertorsionloadsareobtained.Thustheshearstresspropagationandthedebondingprocessofthewholeinterfacefordifferentbondlengthscanbepredicted.Secondly,throughtheanalyticalsolutions,theinfluencesofdifferentbondlengthsontheload-displacementcurveandtheultimateloadarestudied.Thestresstransfermechanism,theinterfacecrackpropagationandtheductilitybehaviorofthejointscanbeexplained.
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简介:这份报纸在陶艺和脱臼包括阶段转变为无弹性的材料行为的纹理粗糙的原子论的模拟论述新方法论在金属的调停的粘性。方法论联合平衡方程和一个修改有限元素方法的原子论的明确的表达。与显著地自由的更少度比那些一个充分原子论的模型并且没有另外的组成的规则但是interatomic力量地,新纹理粗糙(CG)方法被显示在预言材料的非线性的组成的回答并且也复制象阶段转变那样的原子规模的现象可行(在硅和脱臼成核和移植,脱臼环的形成和在单个水晶的叠的差错带子的钻石-Sn)镍。指导在CG和现在的方法论在没有失去必要原子论的特征,当模特儿和无弹性的材料行为的模拟有效、有希望的相应完整的分子的动力学(MD)模拟表演之间的比较。潜在的应用和CG方法的限制也被讨论。
简介:裂口Hopkinson压力酒吧(SHPB)技术被用来与不同钢纤维内容决定反应粉末水泥(RPC)的动态力量。有不同厚度的脉搏shapers的二种类型被认为减少high-frequency-oscillation效果并且在某个变丑范围上完成将近经常的紧张率。像水泥的材料的压缩力量是hydrostatic-stress-dependent,这被知道,并且明显的动态力量改进来自两个静水力学的压力和紧张的效果评价。以便区分他们,数字方法被用来在RPC的动态压缩强度上计算静水力学的应力,然后真紧张率效果的贡献被决定。另外,动态力量和RPC的失败模式上的钢纤维的效果被讨论。
简介:Thedynamicbehavioroftwoparallelsymmetriccracksinapiezoelectricstripunderharmonicanti-planeshearwavesisstudiedusingtheSchmidtmethodforpermeablecracksufaceconditions.Thecracksareparalleltotheedgeofthestrip.BymeansoftheFouriertransform,theproblemcanbesolvedwiththehelpoftwopairsofdualintegralequations.Theseequationsaresolvedusingtheschmidtmethod.Theresultsshowthatthestressandtheelectricdisplacementintensityfactorsdependonthegeometryofthecracks,thefrequencyofincidentwaves,thedistancebetweencracksandthethicknessofthestrip.Itisalsofoundthattheelectricdisplacementintensityfactorsforthepermeablecracksurfaceconditionsaremuchsmallerthanthosefortheimpermeablecracksurfaceconditions.
简介:Thenaturalfrequencies,complexmodesandcriticalspeedsofanaxiallymovingrectangularplate,whichispartiallyimmersedinafluidandsubjectedtoapretension,areinvestigated.Theeffectsoffreesurfacewaves,compressibilityandviscidityofthefluidareneglectedintheanalysis.Thesubsectionfunctionsareusedtodescribethediscontinuouscharacteristicsofthesystemduetopartialimmersion.Theclassicalthinplatetheoryisadoptedtoformulatetheequationsofmotionofavibratingplate.ThevelocitypotentialandBernoulli’sequationareusedtodescribethefluidpressureactingonthemovingplate.Theeffectoffluidonthevibrationsoftheplatemaybeequivalenttotheaddedmassontheplate.Theeffectsofdistanceratio,movingspeed,immersed-depthratio,boundaryconditions,stiffnessratioandaspectratiooftheplateaswellasthefluid-platedensityratiosonthefreevibrationsofthemovingplate-fluidsystemareinvestigated.
简介:Fatiguecrackingtestsofasolderjointwerecarriedoutusingin-situscanningelectronmicroscopy(SEM)technologyundertensileandbendingcyclicloadings.Themethodforpredictingthefatiguelifeisprovidedbasedonthefatiguecrackgrowthrateofthesolderjoint.Theresultsshowthattheeffectoftheloadingtypeonthefatiguecrackgrowthbehaviorofasolderjointcannotbeignored.Inaddition,thefiniteelementanalysisresultshelpquantitativelyestimatetheresponserelationshipbetweensolderjointstructures.Thefatiguecrackinitiationlifeofasolderjointisingoodagreementwiththefatiguelife(N50%)ofatotallyelectronicboardwith36solderjoints.
简介:为angle-interlockwoven的有弹性的行为分析的一个微机械模型陶器的composites在这篇论文被建议。这个模型由在空间,在邻近的纱之间的洞和纱的实际剖面图几何学认为纤维是波动和连续性考虑实际织物结构。基于laminate理论,编织的3D角度联锁的有弹性的性质陶器的composites被预言。交叉的纬的不同数字几乎有一样的有弹性的moduli。陶器的矩阵的厚度在有弹性的moduli上有小效果。当波动比率增加纵的模量减少和另外的幼仔的moduli增加时。在理论预言和试验性的结果之间的好同意在分析编织的3Dangle-interlock的有弹性的性质表明建议模型的可行性陶器的composites。这篇论文的结果验证分析聚酯矩阵composites的方法对编织陶器的composites合适的事实。
简介:在装载的biaxial下面的液体水晶弹性体(LCE)的thermo-order-mechanical行为在这份报纸被学习。为非线性的有弹性的问题的反的方法被强加拉长到薄矩形的样品的biaxial利用。新古典的有弹性的精力和Landau-deGennesnematic被使用免费精力。在飞机压力假设下面,组成的方程被导出。由于装载的强加的biaxial导致的液体晶体分子的可能的重取向,装载轴将有最大的有效主要紧张的非线性的压力紧张关系能有不同表情取决于的在里面飞机。并且免费精力是多好非凸的潜在的功能。是由一些典型装载路径出现,LCE样品将展出各向异性的非线性的有弹性的行为,只要装载没导致液体水晶分子的重取向。当这确实发生了时,压力跳能由于输稳定性为死了的装载发生。
简介:Equilibriumpathsofpost-bucklingaremeasuredforlargeslendernesscolumnspecimensmadeofthefiberreinforcedcompositematerial.Theinfluenceoftheinitialcurvatureisinvestigatedexperimentallyandcomparedwiththeresultoftheinitialpost-bucklingtheory.Boththetheoreticalandexperimentalresultsrevealthatthecolumnwiththeinitialcurvaturehasstablepost-bucklingbe-haviorsandisnotsensitivetotheimperfectionintheformofinitialcurvature.Theexperimentalre-sultsshowthatwhenthelateralbucklingdisplacementislessthan20percentofthecolumnlength,theexperimentalresultsagreewiththeresultsfromthetheoryofinitialpost-bucklingquitewell,whiletheyagreewiththeresultsfromthelargedeflectiontheoryinaquitelargerange.
简介:基于镍的单个水晶superalloy与的低周期的疲劳(LCF)行为[001]取向在T0掳C的中间的温度和T0+的更高的温度被学习在10的经常的低紧张率下面的250掳C?3s?1在周围的空气。superalloy展出了依赖于温度并且使用紧张振幅的周期的紧张压缩不对称现象。破裂表面上的分析证明表面和表面下的扔micropores是主要裂缝开始地点。内部Ta富有的碳化物经常在所有标本被观察。骨折的二种不同类型被frac-togaphy建议。一种类型被模式描绘--我与一台用显微镜裂开在T0+的不平的表面250掳C。而在更低的温度T0C的另外的类型赞成了中的一个或几八面{111}飞机,与正常模式相对照--我生长模式典型地在低装载观察了频率(几Hz)。为二个裂开的模式的失败机制纬鈥?正在砍在T0+在矩阵和纬/纬鈥?接口在T0掳C和裂开的反对ned和矩阵猛抛250掳C。
简介:Inthispaper,thebehavioroftwocollinearcracksinmagneto-electro-elasticcompositematerialunderanti-planeshearstressloadingisstudiedbytheSchmidtmethodforpermeableelectricboundaryconditions.ByusingtheFouriertransform,theproblemcanbesolvedwithasetoftripleintegralequationsinwhichtheunknownvariableisthejumpofdisplacementsacrossthecracksurfaces.Insolvingthetripleintegralequations,theunknownvariableisexpandedinaseriesofJacobipolynomials.Numericalsolutionsareobtained.Itisshownthatthestressfieldisindependentoftheelectricfieldandthemagneticflux.