Study of the computation of stress intensity factor by stress field intensity

Currently, there is some difficulty for the computation of stress intensity factor (SIF) in engineering because of complicated computation. The purpose of this study is to build the relation between SIF and stress field intensity, and to obtain SIF more easily by stress field intensity. The deduction bases on two basic types of crack, which are mode I crack and mode II crack. For mixed mode I, II crack and common complex planar crack problems, stress field equation at crack tip can be obtained by application of superposition principle to two basic types of crack. And then SIF can be computed by substituting the stress field equation obtained into the stress field intensity expression. To verify the proposed method, four types of crack configuration were analyzed. In the analysis, the FE (finite element)-code MSC. Nastran had been used. Results were evaluated by comparing with numerical solution. Relative errors of four crack configurations are less than 5%, and mostly within 1% ~ 3%. It indicates that complex problem's SIF can easily and accurately be computed by proposed method. This method can lend good support to the research in fracture mechanics, such as crack growth problem and fracture failure problems.