Elasto-plastic analysis of crack in metallic foams

To determine the solutions of the well-known problem of a finite width strip with single edge crack,some results on elasto-plastic fracture analysis for metallic foams are reported.Meanwhile,in order to discuss and put an insight into the nonlinear fracture analysis,the Dugdale model for plastic deformation of this configuration for metallic foams is recommended and solved.Combining the asymptotic solution with the Dugdale model and elastic solution,the stress field in the plastic zone and the size of the plastic zone are expressed as analytical forms.Based on Williams expansion method,the estimate of the scale factor is also completed and analyzed.In view of these analytical solutions,the results show the scale factor is a useful parameter for the fracture theory of metallic foams.     

Plane Elasticity and Dislocation of One-Dimensional Hexagonal Quasicrystals with Point Group 6

Plane elasticity theory of one-dimensional hexagonal quasicrystals with point group 6 is proposed and established. As an application of this theory, one typical example of dislocation problem in the quasicrystals is investigated and its exact analytic solution is presented. The result obtained indicates that the stress components of elastic fields of a straight dislocation in the quasicrystals still first order singularity, which is the same as the general crystals, but are related with the Burgers vector of phason fields, which is different from the general crystals.     

Diffusive Wave Model and Its Applications to Biology and Physics

This study presents the diffusive wave model, relevant dispersion law and the applications to the signal transduction of live cells, phason dynamics of quasicrystals, Brownian movement, electro-magnetic field and fluid dynamics fluctuation, respectively. The common features of these diffusive waves are summarized, which present diffusion as well as wave behaviour, or exactly speaking, they present a duality of diffusion and wave or the duality of wave and diffusion. Furthermore, the general nature of the motion is discussed from the point of view of Landau elementary excitation of condensed matter, this may lead to a concept of generalized elementary excitation (or generalized quasiparticle) corresponding to the diffusive wave.     

Mathematical modelling on instability of shear fault

A study on mathematical modelling on instability of fault is reported.The fracture mechanics and fracture dynamics as a basis of the discussion,and the method of complex variable function (including the conformal mapping and approximate conformal mapping) are employed,and some analytic solutions of the problem in closed form are found.The fault body concept is emphasized and the characteristic size of fault body is introduced.The effect of finite size of the fault body and the effect of the fault propagating speed (especially the effect of the high speed) and their influence on the fault instability are discussed.These results further explain the low-stress drop phenomena observed in earthquake source.     

准晶弹性理论中的几个基本定理和守恒积分

目的推广经典晶体弹性理论中的几个基本定理到准晶弹性理论中去．方法推导中利用了准晶弹性理论的基本控制方程和高斯定理．结果与结论本文导出了准晶弹性理论中的虚功原理和Betti功互易定理等,证明了解的唯一性定理,并给出了准晶弹性理论中的一些守恒积分,如广义J-积分．当相位子场为零时,上述结论退化为经典弹性理论中的结论．     

幂硬化材料扩展裂纹的有限元分析

目的研究幂硬化材料中定常扩展裂纹的裂尖场性质．方法采用Euler模式在小范围屈服条件下对幂硬化材料中平面应力定常扩展裂纹的裂尖场进行了弹塑性有限元分析．结果针对硬化指数n＝12的幂硬化材料,有限元计算给出了扩展裂纹裂尖的主塑性区形状、裂纹张开位移和裂尖应力场的角分布．结论数值计算结果表明其与现有的渐近分析解符合较好,验证了分析解．     

一种在立方环网络上加总线的方法

本文提出一种在立方环网络（ＣＣＣ）上加总线的方法，对于小规模的ＣＣＣ网络，这种方法能使其直径降为３；而对于大规模的ＣＣＣ网络，能使其直径降为原来的２／３以下，并且还可以使网络中各结点的度降为≤２。     

一般化超立方网络的容错寻径算法

本文研究一般化超立方网络（ＧＨＣ）的容错寻径算法。给定一个一般化超立方网络Ｇ（ｍ，ｒ）：Ｎ＝ｍ＾ｒ（ｍ≥２，ｒ≥１），Ｆ为其故障结点集合，且Ｇ（ｍ，ｒ）－Ｆ是连通的，Ｓ和Ｄ是Ｇ（ｍ，ｒ）中任意两个非故障结点，其汉明距离Ｈ（Ｓ，Ｄ）＝ｈ，则当故障结点的个数│Ｆ│〈ｄ，一定存在一条长度≤ｈ＋２的非故障路径Ｐ（Ｓ，Ｄ），而当ｄ≤│Ｆ│〈ｍ（ｄ－ｍ＋１）时，一定存在一条长度≤ｈ＋４ｍ－２的非故障路径Ｐ（Ｓ     

十次二维准晶材料的接触问题

准晶作为一种新的固态物质结构给传统的凝聚态物理学带来了深刻的变革 ,其弹性基本方程比传统晶体的弹性基本方程要复杂得多 .通过引入位移函数和应用Fourier分析与对偶积分方程理论圆满解决了在一个平底冲头作用下十次二维准晶材料的接触问题 ,得到了此材料接触问题应力与位移的解析表达式 .结果表明 ,如果接触位移在接触区域内为一常数 ,则垂直接触应力在接触边缘具有 - 1/ 2阶奇异性 ,这为准晶材料的接触变形提供了重要的力学量 .     

纤维增强复合材料断裂的宏微观结合模型

由于纤维增强复合材料内部结构固有的复杂性, 目前还没有一种理论和方法能很好地解决带缺陷的复合材料的断裂问题。本文发展了一种宏微观结合模型, 用有限元方法计算复合材料的断裂问题, 得到了一些有意义的结果。