Study of crack propagation of bump-prone coal sample

A series of studies about the rule of crack propagation and the process of instability in bump-prone coal sample have been carried out by using scanning electron microscope (SEM), image of surface fracture morphology and the numerical method. The results of three-point bending experiment show that the crack is mainly the tear-type crack under quasi-static loading and can be analyzed with the mode I crack theory. The paper deduced the critical length derived from static to dynamic stage based on fracture and damage mechanics theory and introduced the cohesive element. With the cohesive force model of three-point bending notched beam of the sample, the process of the initiation and propagation of crack by using ABAQUS finite element software. This study discussed the energy variety in the whole process, and it is coincide with the experimental results.