缝端奇异边界单元和界面裂缝的应力强度因子计算

Singular boundary elements at crack tip and the stress intensity factors calculation of interfacial crack

虽然不同材料的界面裂缝缝端应力情况很复杂，但是在拉剪荷载作用下，仍然存在主 导缝端奇异特性的特征参数──应力强度因子，且其主导奇异项仍为１／２，因此可以采用１／４ 奇异边界单元模拟缝端的位移场和应力场。作者沿界面引用边界元，在界面裂缝周围引入１／４ 奇异边界元，给出了计算异弹模界面缝复应力强度因子的计算格式，定义了界面裂缝的等效能 量释放率，探讨了界面裂缝的断裂差别指标，并应用于混凝土坝与岩石地基的界面裂缝扩展分 析中，得到一些有关坝工安全的重要提示。

The stress condition of the tip region of inter facial crack between the dissimilar materials is very complicated,nevertheless, the stress intensity factors (SIF) due to tensileshearload remain a near singular field with l/2 singularity at the near-tip region. 1/4 singular boundary elements may be used to simulate the displacement and stress field at crack tip. In present paper,the boundary elements were used to follow the interfacial boundary and the special 1/4 singular boundary elements were introduced around the tip of the interfacial crack. A formula of calculating characteristic complex stress intensity factors for the interfacial crack of dissimilar materials is presented. Equivalent rate of energy release of the interfacial crack was definited. A fracture criterion of inter facial crack is suggested. Study on the interfacial crack was used for the analysis of inter facial crack propagation between concrete dam and rock foundation. The important mentions on dam safety were offered.