Dynamic fracture in a discrete model of a brittle elastic solid

Dynamic fracture of brittle materials is studied by means of a molecular dy namics simulation of a two-dimensional (2D) lattice of point particles. By a particular discretization of the continuum equations of elasticity, we de rive the Born model in such a way that the model parameters are related to the material properties. Numerical simulations are performed, which show a branching instability, under Mode I lending, occurring at a critical crack tip speed. The analysis of the dynamical stress tensor field near the tip s hows a qualitative similarity to Yoffe's stress held.