### 表面裂纹疲劳扩展和寿命计算的高效高精度数值分析方法

1. 1. 浙江工业大学 机械工程学院, 杭州 310012;
2. 义乌工商职业技术学院 机电信息学院, 义乌 322000
• 收稿日期:2017-03-29 修回日期:2017-04-26 出版日期:2017-12-15 发布日期:2017-04-26
• 通讯作者: 柴国钟 E-mail:chaigz@zjut.edu.cn
• 基金资助:
国家自然科学基金（51275471）

### A highly efficient and accurate numerical analysis method for fatigue propagation of surface crack and life prediction

CHAI Guozhong1, LYU Jun1,2, BAO Yumei1, JIANG Xianfeng1, DING Hao1

1. 1. College of Mechanical Engineering, Zhejiang University of Technology, Hangzhou 310012, China;
2. School of Mechatronics & IT, Yiwu Industrial & Commercial College, Yiwu 322000, China
• Received:2017-03-29 Revised:2017-04-26 Online:2017-12-15 Published:2017-04-26
• Supported by:
National Natural Science Foundation of China (51275471)

Abstract: The basic theory and numerical solving technique of the hybrid boundary element method for the calculation of the stress intensity factors of three-dimensional crack is established based on the theory of elastic mechanics. In analyzing the fatigue propagation of the surface crack, the stress intensity factor at each crack propagating step needs to be calculated, and accordingly the large non-symmetric coefficient matrix should be computed repeatedly. A method is proposed that the master matrix is calculated only once in the initial crack state, and then a very small-scale matrix is calculated during the subsequent fatigue crack propagation.The solution for the stress intensity factor is also given in an explicit form without solving large-scale linear algebraic equations so that the calculation efficiency is improved greatly. To address the problem of continuous division and remeshing of elements during the fatigue crack propagating, the hybrid boundary element method is applied as the master matrix is independent of the crack, and therefore only remeshing of elements on the crack surface is required. For the semielliptical surface crack, the elements on the crack surface are remeshed according to the mapping relationship as the crack is mapped into the semicircle in meshing and the elements in the unit semicircle have no change during the fatigue propagation. The accuracy and reliability of the proposed method are verified by several examples and experiments. The research efforts may provide the theoretical foundation and the realization method for highly efficient and accurate numerical analysis of the surface crack fatigue propagation and the life prediction of engineering structures.