Thermal cracking of two-phase composite structures under uniform and non-uniform temperature distributions

Abstract

In this paper curved thermal crack growth in self-stressed brittle solids subjected to well-defined temperature fields has been studied. The resulting boundary-value problems of the stationary plane thermoelasticity are solved by means of the finite element method. Moreover, by applying an appropriate crack growth criterion based on the total energy release rate of a quasistatic mixed-mode crack extension the further development of thermal crack paths starting at the external surfaces of disk-like two-phase compounds with circular cross-sections could be predicted. Several specimen geometries consisting of different material combinations have been investigated by considering uniform temperature changes and by applying the relevant methods of fracture mechanics. Further, the corresponding fracture mechanical data like strain energy release rates and stress intensity factors, respectively, have been determined by additional considerations of the influence of inner stress concentrators onto the paths of quasistatic extending thermal cracks. The comparison of those theoretical investigations with associated cooling experiments shows a satisfying agreement. Finally, the influences of additional local temperature changes onto the prospective thermal crack paths have been studied by means of the fracture criterion mentioned already as well as by using the finite element method. Thereby the numerical results have shown some remarkable effects of interference between the local temperature changes located in the vicinity of thermal crack tips and the further crack paths.