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复合材料有效弹性性质分析方法eeeeee 总被引:35,自引:1,他引:34
建立复合材料的有效性质与微结构参数的关联,是复合材料优化设计的基础。本文具体针对有效弹性性质,重点介绍了建立有效性的基本思路 和主要分析方法。首先讨论了代表单元的概念,然后分别从复合材料有效性质的普适关系、界限理论和近似方法三个不同的视角较全面的介绍了建立非均质材料有效性质的方法、主要结果和最新进展。重点从构型的概念和微结构分布形式上分析了各种模型间及分析方法之间的联系与差别。最后还就建立非均质材料有效性质中存在的问题和研究热点做了简单的介绍。 相似文献
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将纳米晶材料视为包括晶粒和晶界的两相复合材料.基于能量平衡概念推导出纳米晶材料的增量本构关系.最后将本文发展的模型用于纯铜的单轴拉伸实验,讨论了晶粒大小、形状和晶粒分布的影响,并将模型预测的结果和已有的实验结果进行比较. 相似文献
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Fei Deng Quanshui Zheng 《Acta Mechanica Solida Sinica》2009,22(1):1-17
The present article provides supplementary information of previous works of analytic models for predicting conductivity enhancements of carbon nanotube composites. The models, though fairly simple, are able to take account of the effects of conductivity anisotropy, nonstraightness, and aspect ratio of the CNT additives on the conductivity enhancement of the composite and to give predictions agreeing well with existing experimental data. The omitted detailed derivation of this model is demonstrated in the present article with a more systematical analysis, which may help with further development in this direction. Furthermore, the effects of various orientation distributions of CNTs are reported here for the first time. The information may be useful in design or fabrication technology of CNT composites for better or specified conductivities. 相似文献
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颗粒增强复合材料有效性能的三维数值分析 总被引:9,自引:0,他引:9
将细观力学和计算力学方法相结合用以确定复合材料中的局部和平均应力-应变场.对旋转体和非旋转体颗粒增强复合材料的有效模量进行了三维有限元数值计算,数值与实验结果对比表明,该方法是有效的、可靠的.分析了颗粒的排列分布、颗粒取向和颗粒的几何形状对有效模量的影响.数值结果表明,颗粒的排列对有效轴向弹性模量影响较大.颗粒的取向和颗粒的形状对有效性能的影响也是显著的 相似文献
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计算微裂纹损伤材料有效模量的一种简单方法 总被引:7,自引:0,他引:7
给出了一种基于Taylor模型的有效介质方法。用以计算微裂纹相互作用对有效本构关系的影响,该方法假设每一个微裂纹位于一种有效介质之中,该有效介质的弹性模量由不考虑微裂纹相互作用的Taylor模型计算、和自洽方法相比,这种方法计算简单,而且结果更准确。 相似文献
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根据格林函数理论和微扰方法,提出了描述复合材料弹塑性(非线性应力-应变关系)行为的简单理论.对陶瓷颗粒增强金属基复合材料,给出了两个不同的解。SiC/Al复合材料的计算实例表明,理论结果与实验结果是相符合的. 相似文献
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通过解析和数值的方法研究了二维微裂纹体有效模量和有效导电系数之间的关联,针对二维含有任意取向和平行的微裂纹介质,通过基于象素的有限元方法分别计算了它们的有效杨氏模量和有效导电系数,并建立了两种不同物理量之间的关联.研究结果表明利用简单的解析Mori-Tanaka方法也可以建立上述关联,并且与数值结果吻合很好。 相似文献
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通过高温环境下多种纤维材料的体积烧蚀机理的分析,利用细观力学的 Eshelby等效夹杂方法研究了材料烧蚀-相变特性和高温力学性能变化规律.假设材料体积烧蚀后热解相(真空)和氧化相(空气)介质统计均匀分布,考虑了热化学反应产生的气孔与固体相介质之间的相互作用,预报了不同纤维材料弹性模量随温度、加温速率之间的变化关系,并与实验结果对照,吻合较好. 相似文献
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为研究微损伤对非均匀材料宏观破坏的影响,建立了非均匀材料的三维微单元强度分布模型,在平均场模型和集团分担模型的基础上,根据模拟计算结果建立了邻近单元加权分担模型;采用细观统计的方法建立了微观损伤造成宏观破坏的概率函数及跨尺度敏感性函数.结果表明:材料的损伤分数和名义应力越大,破坏集团之间的距离越近,宏观破坏概率就越大;损伤分数较小时,材料的跨尺度敏感性随损伤分数增加而增大;损伤分数较大时,材料的跨尺度敏感性随损伤分数增加而减小;材料的跨尺度敏感性受体系大小影响,体系越大其敏感性越小. 相似文献
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Yongqiang Chen Ruchao Huang Zhuping Huang Lizhi Sun 《Acta Mechanica Solida Sinica》2012,25(3):262-276
This paper studies the effective properties of multi-phase thermoelastic composites. Based on the Helmholtz free energy and the Gibbs free energy of individual phases, the effective elastic tensor, thermal-expansion tensor, and specific heats of the multi-phase composites are derived by means of the volume average of free-energies of these phases. Particular emphasis is placed on the derivation of new analytical expressions of effective specific heats at constant-strain and constant-stress situations, in which a modified Eshelby’s micromechanics theory is developed and the interaction between inclusions is considered. As an illustrative example, the analytical expression of the effective specific heat for a three-phase thermoelastic composite is presented. 相似文献
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论文基于Mori-Tanaka理论,考虑了界面相对超磁致伸缩复合材料的有效性能的影响,得到了具有界面相的超磁致伸缩复合材料的有效性能的一般解析表达.考虑到固化过程中热残余应力对超磁致伸缩复合材料有效性能的影响,通过数值计算,给出超磁致伸缩复合材料有效弹性模量、有效磁致伸缩应变及有效热膨胀系数随夹杂物长径比、体分比、界面参数和固化热残余应力的变化特征曲线,数值结果表明:界面和固化热残余应力对于超磁致复合材料有效性能的影响是显著的. 相似文献
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提出了以圆筒扭转力学模型为基础, 预测周期性多孔材料等效剪切模量及其研究尺寸效
应的一种简单有效计算方法. 以方形孔和圆形孔两种典型多孔材料为例进行了数值计算求解;
同时, 建立了几何参数随体胞尺寸缩放因子$n$的解析关系, 证明了两种构型的周期性多孔材
料的等效剪切模量均随尺寸缩放因子$n$的增大而减小. 当$n \to \infty
$时, 即体胞尺寸相对整体结构无限小时, 多孔材料的等效剪切模量趋近收敛于一个恒定值;
当体胞的材料体分比增大时, 多孔材料等效剪切模量也随之增大. 此外, 依据周
期性多孔材料的结构对称特性, 使用体胞子结构有限元计算模型进行等效剪切模量及其尺寸
效应的预测, 极大地提高了计算效率. 相似文献
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Physical mechanisms and influencing factors on the effective stress coefficient for rock/soil-like porous materials are investigated, based on which equivalent connectivity index is proposed. The equivalent connectivity index, relying on the meso-scale structure of porous material and the property of liquid, denotes the connectivity of pores in Representative Element Area (REA). If the conductivity of the porous material is anisotropic, the equivalent connectivity index is a second order tensor. Based on the basic theories of continuous mechanics and tensor analysis, relationship between area porosity and volumetric porosity of porous materials is deduced. Then a generalized expression, describing the relation between effective stress coefficient tensor and equivalent connectivity tensor of pores, is proposed, and the expression can be applied to isotropic media and also to anisotropic materials. Furthermore, evolution of porosity and equivalent connectivity index of the pore are studied in the strain space, and the method to determine the corresponding functions in expressions above is proposed using genetic algorithm and genetic programming. Two applications show that the results obtained by the method in this paper perfectly agree with the test data. This paper provides an important theoretical support to the coupled hydro-mechanical research. 相似文献
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DETERMINATION OF EFFECTIVE MODULI FOR FOAM PLASTICS BASED ON THREE PHASE SPHEROIDAL MODEL 总被引:3,自引:0,他引:3
Lu Zixing 《Acta Mechanica Solida Sinica》1995,8(4):294-302
The relations of bulk modulus,shear modulus,Young's modulus and the Poisson's ra-tio with porosity of foam plastics are determined by a three phase spheroidal model commonly used inComposite Mechanics.The results are compared with those using differential scheme.It is shownthat the material properties derived from the present model normally are larger than those obtained bydifferential scheme for foam plastics with identical porosity.The differences in shear moduli andYoung's moduli obtained by the two methods are small,but they are larger for bulk moduli of incom-pressible matrix and Poisson's ratios.The Young's moduli of high density foam plastics derived by thepresent model agree better with experimental ones. 相似文献
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基于三相球模型确定泡沫塑料有效模量 总被引:4,自引:0,他引:4
通过复合材料三相球模型确定泡沫塑料的体积模量、剪切模量、杨氏模量和泊松比等材料等参数与材料孔隙比的关系,并将该文结果同微分法得到的结果进行了对比;结果表明:三相球模型确定的材料参数在相同孔隙比情况下,一般都高于微分法确定的结果,两种方法得到的有效剪切模量和杨氏模量差异较小,而体积模量和泊松比则差异较大,然而,由三相球模型确定的泡沫塑料杨氏模量仍可与实验较好地符合。此外,该文结果也同现有的理论及实验 相似文献