有限长界面裂纹对冲击载荷的响应

本文研究了受冲击载荷作用下界面裂纹的瞬态特性。通过引入裂纹尖端附近裂纹面无摩擦接触区,消除了界面裂纹问题中存在的振荡奇异性。由于产生了随时间变化的运动边界,应用积分变换及路径积分方法进行反演,在时间-空间域上给出了问题的控制积分方程。应用chebyshev多项式展开,将问题转化为非线性微分-积分方程组的求解。给出了剪切应力强度因子和裂纹面接触区尺寸的数值结果。所得结果表明,拉伸场中界面裂纹的扩展和剪切失效有密切关系。

IMPACT RESPONSE OF A FINITE INTERFACE CRACK

The transient behaviour of a finite interface crack opened out by normal tractions applied to its surfaces is investigated. The well -known oscillatory singularities are removed by introducing a small region in which the crack surfaces make frictionless contact. A boundary that varies with time appears in the problem. The governing equations of the problem are obtained in space - time domain using integral transforms coupled with technique of contour integral used to invert the transforms. Then the problem is reduced to the solution of a system of nonlinear derivative - integral equations by using Chebyshev polynomial expansions. The numerical results of shear stress intensity factor and the length of the crack face contact region are given. The information gained indicates that the spreading of the interface crack in tension field is intimately connected with failure in shear.