学科分类
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54 个结果
  • 简介:TwogradesofDyneema~?compositelaminateswiththecommercialdesignationsofHB26andHB50werecutintoblockswithorwithoutanedgecrackandcompressedinthelongitudinalfiberdirection.Thecrackedanduncrackedspecimensshowsimilarcompressiveresponsesincludingfailurepatternandfailureload.ThetwogradesofDyneema~?compositesexhibitsdifferentfailuremodes:adiffuse,sinusoidalbucklingpatternforDyneema~?HB50duetoitsweakmatrixconstituentandakinkbandforDyneema~?HB26duetoitsrelativelystrongermatrixconstituent.AneffectivefiniteelementmodelisusedtosimulatethecollapseofDyneema~?composites,andthesensitivityoflaminatecompressiveresponsestotheoveralleffectiveshearmodulus,interlaminarshearstrength,thicknessandimperfectionangleareinvestigated.Thechangeoffailuremodefromkinkbandtosinusoidalbucklingpatternbydecreasingtheinterlaminarshearstrengthisvalidatedbythefiniteelementanalyses.

  • 标签: 复合材料层合板 DYNEEMA 正弦屈曲 失效模式 压缩 层间剪切强度
  • 简介:环境友好thermosettingcomposites被作为矩阵混合小麦面筋(WG)准备,钙碳酸盐(CaCO3)由在120掳C塑造混合到交叉连接的压缩作为可塑剂作为filler和甘油列在后面WG矩阵。形态学观察证明CaCO3粒子细微地在矩阵被驱散。直到进composites的10wt%的CaCO3的加入引起了幼仔的模量和张力的力量显著地增加。在另一方面,在裂缝的潮湿吸收和延伸稍微减少了。

  • 标签: 小麦 谷蛋白 碳酸钙 机械力学
  • 简介:转变地方法(TFM)被开发估计有任意的形状的水晶composites的各向异性的绝缘的性质和水晶包括的绝缘的性质,绝缘的轴与各向异性的水晶的那些其校长不同矩阵。包括形状引起的复杂边界值问题被介绍一个转变电场进水晶composites区域避免,并且有效各向异性的绝缘的回答以转变地被提出。而且,数字结果证明水晶composites的有效各向异性的绝缘的回答周期性地作为在包括和矩阵水晶材料的主要的绝缘的轴之间的旋转角度的功能变化。它被发现那更逍遥法外包括形状导致的包括体积部分有效各向异性的绝缘的回答上的深刻效果。

  • 标签: 各向异性晶体 介电性能 复合材料 各向异性介质 任意形状 反应介质
  • 简介:Inordertoimprovethemechanicalpropertiesofpolypyrrole,compositesweremadebyelectropolymerizingpolypyrroleinapolyurethanematrix.Polypyrrole/polyurethane(PPY/PU)compositefilmscontainingCLO4-,BF4-orCH3-C6H4-SO3-counterionsweremadeinavarietyofsolventsystemsandcharacterizedbySEM,electronicconductivity,FTIR,andmechanicalproperties.Compositefilmsshowingmuchgreaterfiexibilitythanpurepolypyrrolewereobtained,buttheirelectronicconductivitiesweresubstantiallylower.Measuredeonductivitiesrangedfrom0.001to8S/cm,tensilestrengthsfrom44to592psi,andelongationtofailurefrom3to70%.

  • 标签: POLYURETHANE ELONGATION tensile showing polymerization substantially
  • 简介:Thioglycolicacid(TGA)-stabilizedCdTenanocrystals(NCs)werepreparedwithsodiumtelluriteastelluriumsource,whichavoidsthecumbersomeprocessesassociatedwithH2TeorNaHTesources.FluorescentCdTe/SiO2compositesweresynthesizedbyasol-gelmethodwithouttheexchangeofsurfaceligands.ThephasestructureofCdTeNCswasinvestigatedbyX-raydiffractometry.Forcomparison,somecharacterizationsweredoneforboththeCdTeNCsandthecomposites.CdTeNCsandCdTe/SiO2compositeswerecharacterizedwithTEM,digitalcameraandfluorescencespectrophotometer.ThestabilityofCdTeNCsandthecompositeswereinvestigatedinphosphate-bufferedsaline(PBS)bufferandthefluorescentpropertiesofthecompositeswerediscussedindetail.

  • 标签: 复合材料 荧光性质 CdTe纳米晶 合成 磷酸盐缓冲液 透射电子显微镜
  • 简介:在结构的常规基于可靠性的最佳设计,可靠性基于概率假设被计算,并且设计目的和限制被看作确定的。在许多情况中,然而,在那里存在在设计目的和限制功能的一些模糊因素。在这篇论文,模糊可靠性和模糊限制被介绍为把压成薄片的composites建立模糊基于可靠性的最佳模型。方法在这篇论文开发了的例子表演能把考虑给可靠性需求和结构的经济方面。因为模糊reliability-basedoptimum设计是一个“软”的图案,现在的结果为结构的可靠性的有效评估提供新方法论并且带给我们一个其他的最佳设计想法。

  • 标签: 模糊可靠性 模糊约束性 最佳安全水平 模糊综合评估
  • 简介:PP/claycompositeswithdifferentdispersions,namely,exfoliateddispersion,intercalateddispersionandagglomeratesandpanicle-likedispersion,werepreparedbydirectmeltintercalationorcompounding.TheeffectofclaydispersiononthecrystallizationandmorphologyofPPwasinvestigatedviaPLM,SAXSandDSC.Experimentalresultsshowthatexfoliatedclaylayersaremuchmoreefficientthanintercalatedclayandagglomeratesofclayinservingasnucleationagentduetothenano-scaledispersionofclay,resultinginadramaticdecreaseincrystalsize(lamellarthicknessandspherulites)andanincreaseofcrystallizationtemperatureandcrystallizationrate.Ontheotherhand,adecreaseofmeltingtemperatureandcrystallinitywasalsoobservedinPP/claycompositeswithexfoliateddispersion,duetothestronginteractionbetweenPPandclay.Comparedwithexfoliatedclaylayers,theintercalatedclaylayershavealessimportanteffectonthecrystallizationandcrystalmorphology.Noeffectisseenforsampleswithagglomeratesandpanicle-likedispersion,inregardtomeltingtemperature,crystallizationtemperature,crystalthicknessandcrystallinity.

  • 标签: 聚丙烯 粘土 散射 结晶化 形态学
  • 简介:这份报纸学习多相的thermoelasticcomposites的有效性质。把免费精力和吉布斯基于Helmholtz多相的composites的单个阶段,有效有弹性的张肌,热扩大的张肌,和特定的热的免费精力借助于体积一般水准被导出这些阶段免费精力。特别强调以经常紧张、经常压力的状况,修改Eshelby的micromechanics理论在被开发被放在有效的特定的热的新分析表情的推导上,在包括之间的相互作用被考虑。作为一个解说性的例子,为三阶段的thermoelastic的有效的特定的热的分析表示合成被介绍。

  • 标签: 弹性复合材料 有效热 亥姆霍兹自由能 解析表达式 吉布斯自由能 多相复合材料
  • 简介:Despitethewideusageofisotropicfibrouscompositeswithaviscoelasticpolymermatrix,noanalyticmodelfortheirmechanicalbehaviourisknown.Thispaperdevelopssuchamodelfortime-dependentYoung'smodulus,showingthatfortypicalconstituentsthetimeconstantsofcompositesareuptoabout6%greaterthanthematrixsheartimeconstant.Viscoelasticityisstronglysuppressedforstifffibresevenatmodestfibrevolumefractions.Comparisonwithknownresultsforparticleandorientedfibrecompos...

  • 标签:
  • 简介:AnewtypeofSiO_2-MgO-CaO(SMC)whiskerwasusedtomodifyhighdensitypolyethylene(HDPE).Themeltingbehaviorandcrystallinitywereinvestigatedbydifferentialscanningcalorimetry(DSC).ThedispersionofwhiskersandinterfacialadhesioninthepreparedHDPE/SMCwhiskercompositeswereinvestigatedbyscanningelectronmicroscopy(SEM).Themechanicalpropertieswereevaluatedbymechanicaltestsanddynamicmechanicalanalysis(DMA).DSCdataindicatedthatthemeltingtemperatureandthecrystall...

  • 标签: SMC WHISKER POLYETHYLENE MECHANICAL properties.
  • 简介:Themixedmatrixmembranes(MMMs)weredevelopedbyincorporatinggraphiteoxide(GO)flakesfunctionalizedwithironoxide(Fe3O4)intoPebaxmatrix.ThePebax/Fe3O4-GOMMMswereusedtoseparateCO2/CH4andCO2/N2gasmixture.TheresultsshowedthattheMMMswithmagneticalignmentpresentedthebettergasseparationperformancethanthatofrandomarrangementofPebax/Fe3O4-GOmixedmatrixmembranes.ThereasonwasthattheFe3O4-GOflakesarrangedmagneticallyinthemembraneplayedamultipleroleinimprovingtheperformanceofMMMs.Firstly,undertheactionofthemagneticfield,themagneticalignmentofFe3O4-GOflakesinPebaxmatrixconstructedtheshortertransferpathforgasmolecule,increasingtheCO2permeability.Secondly,thehydroxylgroupsinGOflakesandthepresenceofFe3O4havestrongerbindingforceforwater,improvingtheCO2solubilityselectivity.Thirdly,thebetterinteractionbetweenthemagneticalignmentofGOcompositesandpolymermatrix,reducedtheinterfacedefects.Especially,theoptimumgasseparationperformsneewasobtainedattheFe3O4-GOflakescontentof3wt%inPebaxmatrixatverticalarrangementwithselectiv让yof47and75forCO2/CH4andCO2/N2,respectively,andCO2permeabilityof538Barrerat0.2MPaandroomtemperature.

  • 标签: C02 separation The mixed MATRIX membranes
  • 简介:Theapplicabilityandlimitationofseveralquadraticstrengththeorieswereinvestigatedwithrespectto2D-C/SiCand2.5D-C/SiCcomposites.Akindofdamage-basedfailurecriterion,referredtoasD-criterion,isproposedfornonlinearceramiccomposites.Meanwhile,thenewlydevelopedcriterionispreliminarilyvalidatedundertension-shearcombinedloadings.ThepredictionshowsthatthefailureenvelopegivenbyD-criterionislowerthanthatfromTsai–HillandHoffmancriteria.Thisrevealsthatthedamage-basedcriterionisreasonableforevaluationofdamage-dominatedfailurestrength.

  • 标签: C SIC复合材料 平面应力状态 标准 陶瓷复合材料 破坏包络线
  • 简介:Chitosan/cellulosenanocrystals(CS/CNCs)composites与计算机数值控制的不同内容被准备。由于计算机数值控制和计算机数值控制的同类的分散,CS的透明性很好被保留,CS的全面机械性质显著地被改进。而且,因为CS和计算机数值控制是biocompatible材料,获得的composites潜在地是noncytotoxic和罐头的房间增长测试表演满足生物医学的应用的安全要求。这些优点在商业塑料的地里铺平CS的潜在的应用的道路并且鼓励CS同样环境友好的材料和生物医学的材料的使用。

  • 标签: 生物相容性 复合材料 纳米晶体 机械性能 透明度 纤维素
  • 简介:Thisstudyinvestigatedtheinfluenceofvariousorganicallymodifiedmontmorillonites(organoclays)onthestructureandpropertiesofrigidpolyurethanefoam(RPUF)nanocomposites.Theorganoclaysweremodifiedwithcetyltrimethylammoniumbromide(CTAB),methyltallowbis(2-hydroxyethyl)quaternaryammoniumchloride(MT2ETOH)andtris(hydroxymethyl)aminomethane(THMA)anddenotedasCMMT,Cloisite30BandOMMT,respectively.MT2ETOHandTHMAcontainhydroxylgroups,whileTHMAdoesnothavelongaliphatictailinitsmolecule.X-raydiffractionandtransmissionelectronmicroscopyshowthatOMMTandCloisite30BcanbepartiallyexfoliatedintheRPUFnanocompositesbecausetheirintercalatingagentsMT2ETOHandTHMAcanreactwithisocyanate.However,CMMTmodifiedwithnonreactiveCTABismainlyintercalatedintheRPUFmatrices.Atarelativelylowfillercontent,theRPUF/CMMTcompositefoamhasahigherspecificcompressivestrength(theratioofcompressivestrengthagainsttheapparentdensityofthefoams),whileatrelativelyhighfillercontents,RPUF/Cloisite30BandRPUF/OMMTcompositeshavehigherspecificcompressivestrengths,highermodulusandmoreuniformporesizethantheRPUF/CMMTcomposite.

  • 标签: 硬质聚氨酯泡沫塑料 泡沫复合材料 改性蒙脱石 性能 有机改性蒙脱土 十六烷基三甲基溴化铵
  • 简介:Withtheadventofleft-handedmagneticmaterials,itisdesirabletodevelophigh-performancewavedevicesbasedontheirnovelpropertiesofwavepropagation.Thisletterreportsthespecialpropertiesofelasticwavepropagationinmagnetoelasticmultilayeredcompositeswithnegativepermeabilityascomparecdtothoseincounterpartstructureswithpositlvepermeability.Thesenovelpropertiesofelasticwavesarediscernedfromthediversifieddispersioncurves,whichrepresentthepropagationandattenuationcharacteristicsofelasticwaves.Tocomputethesedispersioncurves,themethodofreverberation-raymatrixisextendedfortheanalysisofelasticwavesinmagnctoelasticmultilayeredcomposites.Althoughonlytheresultsofasinglepiezomagneticandabinarymagnetoelasticlayerswithmechanicallyfreeandmagneticallyshortsurfacesaswellaspelrfectinterfaceareillustratedinthenumericalexamples,theanalysisisapplicablelomagnetoelasticmultilayeredstructureswithotherkindsofboundaries/interfaces.

  • 标签: 多层复合材料 弹性波传播 负磁导率 回传射线矩阵法 磁多层结构 传播特性
  • 简介:现在的文章为预言碳nanotubecomposites的传导性改进提供分析模型的以前的工作的增补信息。模型相当简单,能在传导性改进上考虑CNT添加剂的传导性anisotropy,非笔直,和方面比率的效果合成并且给与存在试验性的数据同意很好的预言。这个模型的省略详细推导与更系统的分析在现在的文章被表明,它可以在这个方向帮助做好进一步的开发。而且,CNT的各种各样的取向分布的效果第一次这里被报导。信息可能在设计或为更好或指定的传导性的CNTcomposites的制造技术是有用的。

  • 标签: 碳纳米管复合材料 电导率 网络 预测模型 各向异性 实验数据