Prediction model of notch stress field and N-SIF in anisotropic composite materials: Semi-analytical formula and fatigue test

Because of the notch stress singularity, the research on notch stress field and fatigue evaluation of anisotropic V-notch plate has always been the focus of safety evaluation. For anisotropic materials, the notch stress field is not only related to the geometric size and opening angle, but also closely related to the material parameters in all directions. The accurate characterization of notch stress field is the key to evaluate stress concentration and fatigue life of notched structures. By introducing singular strength factor, the semi-analytical formula of stress field in vertical crack direction is deduced theoretically. On the basis of theoretical formula, combined with a large number of numerical model results, a simplified formula of notch stress field under bending load or tensile load is fitted and recommended. Finally, through a series of fatigue tests of V-notched laminates, the notch stress field and fatigue life are obtained, and the formula of notch stress field and fatigue assessment method proposed in this paper are verified. The verification results show that the proposed notch stress field and N-SIF formulas have high prediction accuracy, which provides a reference for the rapid evaluation of notch stress field and fatigue life of anisotropic materials.