分析表面裂纹的一种新方法

用边界积分方法，分析表面裂纹的张开位移和应力强度因子．此方法将埋在无穷大弹性介质中裂纹，模拟为连续分布的位错环．根据两个位错环之间的相互作用能，可以得到弹性体的应变能；对弹性体的势能取极值，可以得到关于裂纹张开位移的边界积分方程．通过把半空间的边界模拟成一个包含在无穷大弹性介质中大裂纹，此法能很好的处理具有任意表面形状的表面裂纹．两个实验算例的计算结果与已有的解析解吻合很好，说明此方法的有效性和精确性．文中还分析具有表面台阶的表面裂纹的应力强度因子，结果有利于分析表面裂纹的扩展．

A New Method for Analysing Surface Cracking

The boundary integral method is applied to the analysis of opening displacement and stress intensity factor of surface crack. The method simulates the crack hiding in infinitely large elastic media as dislocation loop in continuous distribution. According to interaction energy between two dislocation loops, we can obtain strain energy of elastic body; to take extrema from potential energy of elastic body, we can obtain boundary integral equation for the opening displacement of cracking. This method simulates the boundary in half-space into a large crack containing in an infinitely great elastic medium, by which the surface crack in arbitrary shape can be well-treated. The reckoning of two test examples is in good agreement with analytic solution now available, which accounts for the validity and the accuracy of this method. The authors also analyse the stress intensity factor of the surface crack with surface step ,the results is beneficial to determine the direction of crack growth.