Discrete element simulation of compression failure mechanism of SiC ceramic considering collinear flaws.

A particle-based numerical simulation model was established for SiC ceramics, and a method of deleting the particles along the specified direction was chosen to produce a pair of pre-existing collinear flaws. A serial of simulations were carried out to investigate the effects of inclination angle and ligament length on the failure mechanism under uniaxial compression. The laws of crack initiation and propagation as well as the distribution laws of the stress field and displacement field around the pre-existing flaws were analyzed. The results showed that the influence of inclination angle θ on micro-crack initiation, propagation and coalescence was more significant than that of ligament length L for pre-existing collinear flaws. Meanwhile, three coalescence models can be found with the increase of the inclination angle. By analyzing the evolution process of the displacement and stress fields during the loading process, it was clearly that the first crack was induced by the tensile stress concentration, and the secondary crack was initiated and propagated with tensile and shear stress. Moreover, the propagation mechanism of the micro-crack was closely related to the evolution behaviours of the stress and displacement fields.