A semi-analytical quasi-brittle fracture criterion for elliptical notches

The elliptical notch is a widely used model to investigate the failure due to stress concentrations. Although the size effect of the fracture strength of elliptical notches has been studied by many researches, it is still desirable to reveal a clearer physical mechanism. For this purpose, a fracture criterion is proposed in this paper based on an effective stress intensity factor that considers the fracture process zone. This work is greatly facilitated by a semi-analytical stress intensity factor for symmetric cracks around the elliptical notch established with the guidance of the complex potential method. Comparisons with experimental results demonstrate that this criterion has strong predictive power. In addition, the relationship between this criterion and the theory of critical distances is especially highlighted, presenting a clear physical image of this method.