Abstract
Stress intensity factors in cracked bodies have been calculated by various calculation methods. Especially, the typical conventional method ; i. e., stress extrapolation method or displacement extrapolation method has an important advantage, namely convenience. But the accuracy of stress intensity factor by the methods is not so high because of error due to high order terms. In this paper, errors of stress intensity factors by the stress extrapolation method and the displacement extrapolation were investigated on a mixture mode-type crack model in an infinite plate. Finally, an improved technique called V-line extrapolation method is proposed to decrease the curvature of calculated extrapolation data, therefore higher accuracy can be obtained.