Effects of thermoelasticity and a von mises condition in rapid steady-state quasi-brittle fracture

steady-state crack growth in a coupled thermoelastic solid at room temperature is considered. The process is quasi-brittle in the sense that a Dugdale inelastic zone forms ahead of the crack. However, the yield condition defining the zone is of the multiaxial von Mises type, which introduces a non-linear condition into the analysis. This zone also acts as an effective heat source for the surrounding thermoelastic material. The zone heat flux function is not known initially, however, but is treated as a process parameter. The associated mixed boundary value problem is solved by a Wiener-Hopf technique, and experimentally-based values for the crack speed and near-crack temperature rise then imposed. This calibration process allows comparisons of the model with standard Dugdale models in non-thermal solids to be made without having to impose a complete fracture criterion. Results show that coupled thermoelasticity and the von Mises condition enhance both inelastic zone size and dynamic fracture toughness, and that this effect increases with crack speed. The zone length values also show agreement with experimentally-based calculations. Copyright 0 1996 Published by Elsevier Science Ltd.