Crack path prediction in brittle solids by a new discontinuous-like FE approach

The numerical prediction of crack paths in brittle or quasi-brittle solids is difficult from a computational point of view, and non-uniqueness of the solution can occur. To solve such a problem, several computational techniques have been proposed such as ad hoc remeshing strategies, strain softening in the context of plasticity, discontinuous finite elements. In the present paper, a continuum finite element (FE) formulation to model the discontinuity of the displacement field in fracture occurring in brittle or quasi-brittle solids is proposed. A homogeneous discontinuity is assumed to exist in a cracked finite element, and a new simple stress-based implementation of the displacement discontinuity is introduced by an appropriate stress field relaxation in order to simulate the mechanical effects of the crack. The model requires the definition of crack-bridging stress laws. Simple 2D fracture problems are solved to investigate some computational aspects of the proposed algorithm, such as the mesh independence. Finally, the developed numerical model is used to simulate experimental results.