PERIDYNAMIC MODELLING AND ANALYSIS FOR CRACK PROPAGATION IN BRITTLE MATERIALS SUBJECTED TO BIAXIAL DYNAMIC LOAD

A kernel function reflecting the internal length effect of long-range forces has been introduced into a regular micropolar prototype elastic brittle peridynamic model, in order to improve the calculation accuracy and numerical stability of convergence. The proposed model and algorithms were validated through deformation calculation and simulation of crack propagation in a center-notched quasi-brittle plate subjected to a biaxial dynamic load. The crack initiation, propagation and branching can be described naturally by using the proposed approach. The failure mechanism as well as the influence of the direction and distance between two parallel cracks on the failure mode, cracking time, and the extreme failure load of a brittle plate subjected to biaxial dynamic loads have been analyzed further. Numerical results show that the directions of pre-existed cracks as well as the distance between cracks take an important effect on the failure mechanism of the plate. With given crack orientation, the plate shows higher loading capacity when the distance between two parallel pre-existed cracks increases. In the multiple-crack propagation process under biaxial dynamic loads, the pre-existed cracks connect to each other firstly without bifurcation, and then the converged cracks will bifurcate and re-branch when propagate to the boundary.