Notch failure versus interior failure for mixed-mode in-plane loading

This paper uses the linear-elastic Theory of Critical Distances (TCD) to verify and quantify the analysis of a particular central fracture mode occurring in the classical double-cracked flat plate specimen subjected to mixed mode I / mode II loading. Analytical formulae for estimating the critical loading condition for such a special central fracture mode of double-cracked flat plate specimen are derived using both standard elastic beam theory and the TCD. The influence of the crack length, specimen geometry and material parameters on the critical loading angle for such a special central fracture mode is discussed in detail. Finally, in order to verify the proposed central fracture prediction formulae, linear elastic stress analyses for two double-cracked flat plate specimens made of different materials and having different loading angles were conducted using finite element analysis. The results in this study confirm the possibility of interior fracture modes and provide insight on the mechanism of analogous interior fracture occurring in practical applications.