Mesh and timestep sensitivity of fracture from thermal strains using peridynamics implemented in Abaqus

This paper investigates how a bi-material strip, modelled using bond-based peridynamics implemented into the finite element (FE) code Abaqus/Standard, using truss elements, delaminates when subjected to regular uniform temperature changes. It has been found that for both heating and cooling, a crack grows inwards along the interface, which separates the two layers completely. In both cases, microcracks also form perpendicular to the interface, which adapt to loads by either arresting or curving. The crack patterns appear unaffected by mesh coarseness in a δ-convergence test, except when cracks merge due to lack of resolution. However, changing the length of the implicit timestep used, and therefore the induced thermal strain per step, strongly affects the number and distribution of microcracks, which vanish completely for very small timesteps. A simulated thermal shock yielded more evenly spaced, longer microcracks due to the stresses built up during the thermal shock.