正交各向异性材料裂纹疲劳扩展的扩展有限元法研究

Crack Fatigue Propagation in Orthotropic Materials by Extended Finite Element Method

介绍了复合材料的发展与扩展有限元的基础,通过使用最大周向应力准则确定裂纹的扩展方向,使用Paris公式确定裂纹的扩展速度,求得裂纹的疲劳扩展规律。用对比验证算例确定了程序的正确性。对不同的加载条件和材料主方向角度进行模拟,得到材料的S-N曲线。随着循环次数的增加,裂纹的长度增长的越来越快,同时应力强度因子增长的越来越快。随着材料主方向角度的增加,裂纹扩展速度在60°时为最慢,同时扩展角度变化为反正弦变化。

This paper introduces the development of composite materials and the basis of extended finite element method.The stress intensity factor under mixed loading is determined by using interaction integral method,the direction of crack propagation is determined by using maximum circumferential stress criterion,and the propagation speed of crack is determined by using Paris formula,thus the fatigue propagation law of crack is obtained.The correctness of the program is confirmed by a comparative example.The S-N curves of materials are obtained by simulating different loading conditions and main direction angles.With the increase of the number of cycles,the crack length increases faster and faster,and the stress intensity factor increases faster and faster.With the increase of the main direction angle of the material,the crack propagation speed is the slowest at 60 degrees,and the propagation angle changes like the arcsine law.