简介：Theload-bearingcapacitiesofduclilecompositematerialsandstructuresarestudiedbymeansofacombinedmicro/macromechanicsapproach.Firstly,onthemicroscopicscale,theaimistogetthemacroscopicstrengthdomainsbymeansofthehomogenizationtheoryofmicromechanics.Arepresentativevolumeelement(RVE)isselectedtoreflectthemicrostructuresofthecompositematerials.Byintroducingthehomogenizationtheoryintothekinematiclimittheoremofplasticlimitanalysis,anoptimizationformaltodirectlycalculatethelimitloadsoftheRVEisobtained.Andthemacroscopicyieldcriterioncanbedeter-minedaccordingtotherelationbetweenmacroscopicandmicroscopicfields.Secondly,onthemacroscopicscale,byintroducingtheHill’syieldcriterionintothekinematiclimittheorem,thelimitloadsoforthotropicstructuressuchasunidirectionalfiber-reinforcedcompositestructuresareworkedout.Thefiniteelementmodelingofthekinematiclimitanalysisisdeducedintoanonlinearmathematicalprogrammingwithequality-constraintconditionsthatcanbesolvedbymeansofadirectiterativealgorithm.Finally,someexamplesareillustratedtoshowtheapplicationofthepresentapproach.

简介：在这份报纸，静态、动态的开车进入用餐的餐厅电压上的开的裂缝的效果一静电地激活修理改正并且伸臂微光束被调查。由介绍数学建模，管理静电干扰和动态方程被SSLM和基于Galerkin的减少的顺序模型分别地解决。然后，在微光束的各单个方面的开的快克到一个无团的旋转弹簧和击碎的模式形状被建模，相应自然频率由考虑边界并且修正条件并且使用转移矩阵方法是计算的。最后，微光束的开车进入用餐的餐厅电压上的裂缝深度比率，裂缝位置和裂缝数字的效果被学习。在在用机器制造的过程创造的剩余压力旁边，裂缝能被开始，这被显示出，生长并且因而由减少改变系统的开车进入用餐的餐厅电压自然频率。结果证明裂缝位置在在减少的裂缝深度比率旁边是有效的开车进入用餐的餐厅电压。另外，在修理改正的微光束，为在的裂缝地点有几个点，这被显示出，开车进入用餐的餐厅电压是极值。

简介：Amodifiedtorsionpendulumapparatusisdevelopedformeasuringtheshearmodulusofsinglefilamentswithuniformmicro-sizeddiameter.Asinglefilamentfixedatbothendsandwitharing-shapedmassattachedatthemiddleisusedasaclamped-clampedtorsionpendulum.Theshearmodulusofsinglefilamentscanbeexpressedasafunctionoftheoscillationfrequencyofthetorsionpendulum.TheoscillationmotionismeasuredwithaCCDlaserdisplacementsensor,anditsfrequencyisdeterminedbytheFastFourierTransform(FFT)method.Theshearmoduliofthreetypesoffilaments:copperwires,tungstenwiresandcarbonfibersareaccuratelymeasuredwiththistechnique.Itisfoundthatthesizeeffectinshearmoduliofbothcopperwiresandtungstenwiresisminor.Finally,theerroranalysisofourmeasurementtechniqueispresentedindetail.

简介：Westudiedthecoupleddynamicbehaviorofaquartz-crystal-resonator(QCR)/microbeamssysteminthethickness-shearmotions.Throughtakingintoaccountthecouplestressinthedynamicequationsofthequartzplate,bothcontinuousconditionsofshearforceandbendingmomentattheresonator/micro-beamsinterfacearerealized.FrequencyshiftofthecompoundQCRsysteminducedbymicro-beamsisstudiedindetail.Theobtainedresultsareusefulindevicedesignandfrequency-stabilityanalysisofquartzcrystalresonators.

简介：Inthispaper,thefractureprocessofaunidirectionalCF/SiCsingleedge-notchedbeam(SENB)underthree-pointbending(TPB)isstudiedbymeansofmacro/micro-statisticalMonteCarlosimulation.Thesimulatedp-△curvesareinagreementwiththeexperimentalresultsbeforethepeaksofcurves,andthesimulatedmicroevolutionpatternsareinagreementwiththepatternsofthecracksurfaces,whichhaveverifiedthismethod.ItispreliminarilydemonstratedthatthesecondturningpointinthecompliancechangingratecurvecorrespondstothefractureinitiationforexperimentsonSENBunderTPBofunidirectionalCF/SiCcomposites.