表面裂纹的分区混合元分析

ANALYSIS OF SURFACE CRACK BY SUB-REGION MIXED FEM

本文对三维体表面裂纹问题进行分析,应用应力和位移的渐近解在表面裂纹区域构造一个奇异应力单元,采用分区混合有限元法计算裂纹顶端各个位置的应力强度因子。

in this paper, a general solution technique is outlined for the case of surface craoks in a three dimensional body. Around the crack front, a singular stress element is constructed on the basis of a known asymptotic solution of the problem under consideration. Numerical results are reported that are obtained with the proposed sub-region mixed finite element approach. The results are compared with those given in the literature for different situations showing that they are accurate with a much lower computational effort. The proposed method offers the following advantages: 1. the singular stress element possesses the square root singular stress behavior, so an expensive mesh refinement in the stress concentration region is avoided. 2. Since the stress intensity factors are obtained directlly, the accuracy loss in the computational process is decreased. 3. The conjunction conditions of displacements and stresses on the interface between both region. Ⅰ and Ⅱ, are satisfied in an integral sense and the convergence of the solution is thus guaranteed.