Abstract:

Based on the research of the propagation paths of the wing cracks under uniaxial compression by the methods of experiments and numerical simulation. It is found that the wing crack extend along a curved path and gradually approximate to the line which passes the middle point of the main crack and is parallel to the direction of maximum principal stress. According to the geometric characteristics of the wing crack paths, a hyperbolic equation is set up to describe the curved paths of wing cracks approximately. In the equation, the unknown parameters are determined by the crack initiation angle, the crack length and the angle between the direction of the maximum principal stress and the crack surface. Then the comparative analysis of the paths by the hyperbolic equation and the experiments is made; and the results show that the paths by the hyperbolic equation are in concordance with those by experiments, so as to prove that the hyperbolic equation can be used to describe the propagation paths of wing cracks under compression. Furthermore, the stress intensity factors along the hyperbolic path are calculated by ABAQUS; then the extending loads of the wing cracks are analyzed. Through comparing with the experiment results, it is found that the extending loads by the hyperbolic wing cracks fit better with ones by the experiments so as to show validity of the results in the paper.

Key words: wing crack, propagation path, stress intensity factor, uniaxial compression, rock fracture