中文摘要：

在常规有限元单元形函数中加入模拟裂纹不连续位移场的跳跃函数，在裂纹尖端构造反映位移场奇异性的裂尖增强函数，采用相互作用积分法求得裂尖应力强度因子．算例结果表明，扩展有限元方法在分析断裂力学问题时具有计算精度高，对有限元网格依赖性小，操作简便等优点．

英文摘要：

Based on the traditional finite element shape functions, Heaviside functions were introduced to simulate the discontinuity in the displacement field of a crack, and the near crack tip enrichment functions were constructed to represent the near tip asymptotic field, an interaction integral method was adopted to calculate the stress intensity factors. The results show that the extended finite element method has high precision in the analysis of fracture mechanics problems, and that the crack location was independent of the FEM mesh, which provides a simple and efficient treatment of cracks.