Prediction of crack initiation angle in brittle structures containing inclined cracks

Abstract

In computational fracture mechanics, prediction of crack initiation angle is a crucial role on determining the shape of incrementally growing crack profiles and resulting fatigue lives. In some fatigue problems, such as containing inclined cracks, depending on the types of loading, boundary conditions and problem geometry, cracks can grow in a curvilinear form. In this study, fracture behavior of different specimen types made of marble and PMMA are analyzed analytically in terms of prediction of crack initiation angle. Analytical predictions are carried out using a recently developed crack deflection angle equation for three different problems selected from the literature; a square plate containing an inclined central crack subjected to biaxial loading, a short beam bend (SBB) specimen containing an inclined edge crack subjected to three-point bending and an edge cracked triangular (ECT) specimen subjected to three-point bending. Comparison of obtained results with the available data from the literature showed close agreement. Thus, it is concluded that the recently developed criterion is capable and can be used to predict crack initiation angle for brittle materials with inclined cracks.