三维裂纹体应力强度因子的计算

本文采用塌缩三棱柱形奇异单元的位移计算应力强度因子，给出了一个新的全三维外推公式，它是Ｃｈｅｎ和Ｋｕａｎｇ公式〔１３〕的全三维推广，特例证明，它的精度比Ｉｎ－ｇｒａｆｆｅａ和Ｍａｎｕ的公式〔８〕高一阶。数值计算表明，结果稳定和对单元尺寸改变不敏感     

变分法在含边裂纹正交各向异性板中的应用

文中给出了含边裂纹正交各向异性板问题的特征函数展开式，然后利用变分法及边值条件确定展开式中的未知系数，从而可求得裂端应力强度因子。该方法即可应用于应力边界值和位移边界值问题，又适应混合边界值问题。数值计算结果证实了该方法的有效性。     

无侧移半刚性连接组合框架的稳定分析:(Ⅰ)柱的有效长度系数方程

本文基于钢结构设计规范GB50017-2003,利用三柱子框架模型,考虑了连接的非线性弯矩-转角关系和楼板组合效应的影响,推导了无侧移半刚性连接组合框架柱的有效长度系数方程式,同时考虑了梁端和柱远端不同约束情况对有效长度系数的影响。另外,分析了GB50017规范附录D表D-1求解的精确性。研究表明,当柱远端刚接时,推导的方程式类似于GB50017规范附录D表D-1给出的无侧移刚接框架柱的有效长度系数计算公式;对于三柱子框架模型,当柱远端铰接时,用GB50017规范附录D表D-1得到的有效长度系数设计柱是不安全的,但最大误差只有11%。     

功能梯度压电材料反平面裂纹问题

基于三维弹性理论和压电理论，导出了材料系数在横观各向同性平面内梯度分布的压电体的状态方程，进而对材料系数指数函数规律分布的半无限大压电体中的反平面裂纹问题进行了求解，利用Fourier变换给出了半无限大压电体中位移，应力，电势及电位移的解析表达式，并求得了裂纹尖端的应力强度因子和电位移强度因子，分析了不同的非均匀材料系数及几何尺寸对它们的影响。     

Strain energy density of a circular cavity buried in semi-infinite functionally graded materials subjected to shear waves

In this paper, based on the theory of multiple scattering of elastic waves, employing wave functions expansion method, multiple scattering and strain energy density in semi-infinite functional graded materials with a circular cavity are investigated, the analytical solution of the problem is derived, and the numerical solution of the strain energy density factors around the cavity is also presented. The effects of the distance between the cavity and the edge of the materials, the wave number and the non-homogeneous parameter of materials on strain energy density factors are analyzed. From analysis, it can be seen that when the non-homogeneous parameter of materials is less than zero, it has less influence on the maximum strain energy density factor around the cavity; however, it has greater influence on the distribution of strain energy density factors around the cavity. When the non-homogeneous parameter of materials is greater than zero, it has greater influence on both the maximum strain energy density factor and the distribution of strain energy density factor around the cavity, especially in the case that the distance between the cavity and the edge is comparatively little.     

Modélisation de fissures elliptiques internes par hybridation de fonctions de poidsEmbedded elliptical cracks modeling with hybridization of weight functions

A method improving the evaluation of the stress intensity factor by hybridization of two weight functions is presented and applied to embedded elliptical cracks under various loadings. The hybridization consists in using one or the other function in the zone of the crack where it is the most efficient. The delimitation of the two zones is achieved after optimizing the axes ratio and the curvature radius of the crack. During this optimization we seek to reduce the effects of the singularities present in the weight functions as well as to take better into account the influence of the ellipse curvature. To cite this article: B. El Khalil Hachi et al., C. R. Mecanique 334 (2006).     

正交异性平面内的椭圆孔或裂纹系问题

应用Ｆａｂｅｒ级数展开和各向异性体平面问题复应力函数的方法，对于含有任意个椭圆孔或裂纹的正交异性平面，给出了孔周应力场解或孔附近裂纹应力强度因子解，其特例与前人结果一致．     

稠密流体中双原子分子振动弛豫的非谐性及质量效应

利用分子动力学计算机模拟方法研究了稠密流体中双原子分子的振动弛豫问题，证实了双原产分子的振动弛豫速率随着其非谐性的增大而加快，同时，其速率也随其质量因子的变大而加速。     

Moving crack for functionally grated material in an infinite length strip under antiplane shear

Considered is a Yoffe crack in an infinite strip of functionally grated material (FGM) subjected to antiplane shear. The shear moduli in two directions of FGM are assumed to be of exponential form. The dynamic stress intensity factor and strain energy density factor at the crack tip are obtained by using integral transforms and dual-integral equations. The numerical results show that the decrease of the strain energy density factor varies with the shear moduli gradient, and the increase of the strain energy density factor varies with the increase of the moving crack speed. The ratio of shear moduli in material vertical orientation has a great influence on the strain energy density factor.     

Variation of the stress intensity factor along the front of a 3-D rectangular crack subjected to mixed-mode load

Summary  The singular integral equation method is applied to the calculation of the stress intensity factor at the front of a rectangular crack subjected to mixed-mode load. The stress field induced by a body force doublet is used as a fundamental solution. The problem is formulated as a system of integral equations with r ⁻³-singularities. In solving the integral equations, unknown functions of body-force densities are approximated by the product of polynomial and fundamental densities. The fundamental densities are chosen to express two-dimensional cracks in an infinite body for the limiting cases of the aspect ratio of the rectangle. The present method yields rapidly converging numerical results and satisfies boundary conditions all over the crack boundary. A smooth distribution of the stress intensity factor along the crack front is presented for various crack shapes and different Poisson's ratio. Received 5 March 2002; accepted for publication 2 July 2002