A Consideration on the Finite Element Method for Calculating Stress Intensity Factor K_I using the J-Integral Method

In determining the stress intensity factor K_I, the direct application of the finite element method gives poor results in the accuracy, but the J-Integral method developed by Rice can be expected somewhat good accuracy for relatively coarse meshes. Recently Yamamoto et al. have proposed a calculation method based on superposition of analytical and finite element solution. They obtained fairly good results. The purpose of this paper is to get good accuracy for extremely coarse meshes by the application of J-Integral method to the superposition method. The numerical calculations were performed for such three cases as center cracked, symmetrical edge cracked and single edge cracked rectangular plates (aspect ratio, L/W=1.4) using 215,110 and 35 meshes. The calculated values for the correction factor, F(a/W) were obtained within 1～3% against the exact solution for every cases.