An object-oriented approach for modeling and simulation of crack growth in cyclically loaded structures

We present an object-oriented modeling frame for simulating crack propagation due to cyclic loadings. Central to the approach is that the crack propagates when a user-defined propagation criterion is fulfilled, i.e., the crack propagation rate is not prescribed but predicted. The approach utilizes the commercial finite element software package ABAQUS and its associated Python based scripting interface. The crack propagation is simulated by a generalized node release technique. If the propagation criteria are satisfied in the end of a cycle, the crack is allowed to propagate. The incremental crack growth is inferred from an iterative investigation of the propagation criteria. The propagation criteria are user-defined, and can be based on any parameter or parameter set that can be obtained from the simulations. We illustrate the developed modeling frame by two benchmark problems, where the propagation criterion is based on the dissipated energy in the vicinity of the crack tip.