Computational procedures and energy integral for dynamic fracture in viscoplastic materials

A two-dimensional finite element computer program designed for the simulation of dynamic and quasi-static fracture is described. Special algorithms are explained for modeling of crack propagation, viscoplastic material behavior, and the calculation of the T^*-integral. The T^*-integral is a very general energy integral relevant to crack propagation in viscoplastic materials and includes most other proposed energy integrals as special cases. Several critical issues in the simulation of fracture experiments are discussed, particularly the sensitivity of the energy integrals to mesh size. A converged value of T^* can be calculated if a small region of the area integral is excluded. The physical meaning of energy integrals in general as well as T^* with such an exclusion is considered.