Numerical modeling of crack growth under dynamic loading conditions

A framework for modeling crack growth is described that is based on introducing one or more cohesive surfaces into a continuum. Constitutive relations are specified independently for the material and for the cohesive surfaces. Fracture emerges as a natural outcome of the deformation process, without introducing an additional failure criterion. The characterization of the mechanical response of a cohesive surface involves both an interfacial strength and the work of separation per unit area, which introduces a characteristic length into the formulation. Finite element analyses are carried out for a plane strain block with an initial central crack, subject to impact loading. The crack is constrained to grow along the initial crack line. Numerical results are presented for elastic and elastic-viscoplastic solids using various degrees of mesh refinement.