学科分类
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5 个结果
  • 简介:TensileimpactexperimentsofEC8.0-24×7glassfiberbundlesatdifferentlowtempera-turesT(14℃,-40℃and-100℃)andstrainratesεwerecarriedout,andcompletestress-straincurveswereobtained.Withintherangeoftheexperimenttemperaturesandstrainrates,itisfoundthattheinitialmodulusE,theultimatestrengthσmaxandtheunstablestrainεboftheglassfiberbundlesallincreasewithatanidenticalT.Atanidenticalε,withthedecreaseofT,Eandσmaxincrease;butεbincreaseswhen14℃>T>-40℃anddecreaseswhen-40℃>T>-100℃.Thestrain-rate-andtemperature-depen-dentbimodalWeibullstatisticalconstitutivetheorywasadoptedforthestatisticalanalysisoftheexperimentalresults,andtheWeibullparametersofsinglefiberwereobtained.TheresultsshowthatthebimodalWeibulldistributionfunctionissuitabletorepresentthestrengthdistributionoftheglassfiberatlowtemperatureanddifferentstrainrates.ThedifferencesinthemechanicalpropertiesbetweenEC8.0-24×7andEC5.5-12×14glassfiberbundleswerealsodiscussed.

  • 标签: GLASS FIBER low temperature TENSILE IMPACT
  • 简介:Lowcyclefatiguecrackpropagation(FCP)behavioroftwoPC/ABSblendswithaweightra-tioofPCtoABSbeing80/20and60/40,respectively,isinvestigated.Experimentsarecarriedoutbyusingstandardcompacttension(CT)specimens.Thefracturesurfacesareexaminedwithascanningelectronmi-croscope(SEM).ItisshownthattheFCPresistanceofPC/ABSblendwith20%ABSparticlesishigherthanthatofPC/ABSblendwith40%ABSparticles.ItisfoundthatproperABSparticlecontentcanresultinthetougheningofPC/ABSblendsthroughparticlecavitationandshearyieldinginmatrix.

  • 标签: polymer BLEND POLYCARBONATE ACRYLONITRILE-BUTADIENE-STYRENE fatigue CRACK
  • 简介:Anumericalsimulationofstochasticdamaseevolutionprocessintheconditionoflowcyclefatigueloadingisdiscussed.Therelationsbetweendamagevariablesandmicro-cracksareob-tainedbymeansofthemicro-mechanicsmodeloftherepresentativevolumeelementproposedbyLemaitreandDufailiy.Thestochasticinitialdamagevaluesareintroducedinconsiderationoftheinherentmicro-defectsinmaterials.Themodelcombinedwithafiniteelementmethodisappliedtosimulatethedamageevolutionprocessunderlowcyclefatigueloading.Themicro-cracksonthesurfaceofaspecimenof19Mn6alloysteelaremeasuredwithareplicatechnique.Thenumericalresultsshowthatthenor.homogeneityofdamageandthelocalizationofthefatiguefailurearewellshownbytheproposedsimulations,andthefatiguelivesarereasonablypredicted.

  • 标签: STOCHASTIC DAMAGE MICRO-MECHANICS model low CYCLE
  • 简介:原子是保持完整通过象化学契约那样的短范围相互作用和电磁的相互作用形成不同材料和设备。当分子的力学和动力学基于实验潜力能在大规模模仿材料行为时,量力学是强大的在纳米规模描述材料的短范围相互作用,但是在包括费用转移和再分配过程处理弱,例如功能的nanomaterials,塑料变丑,骨折和nanomaterials的阶段转变的机械电的联合。这些问题对需要被延长到货车derWaals距离和更大的空间以及时间的规模的量力学也挑战性。这里,我们使一些的这种机械行为上的简短评论和讨论成为重要功能的nanomaterials和nanostructures,到探查到多尺度的物理力学的nanomechanics和趋势的边疆。

  • 标签: 低维纳米材料 电磁相互作用 塑性变形 中间层 强度 相变
  • 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。

  • 标签: 低循环疲劳 单晶 高温合金 温度条件