Periodic surface cracks in an interpenetrating phase composite under a thermal shock

Abstract

We consider a strip of an interpenetrating phase composite (IPC) with periodic cracks at both edges of the strip under a thermal shock. A local thermal non-equilibrium (LTNE) model is employed to capture the effect of three-dimensional interpenetrating networks of the constituents on the temperature distributions in the IPC strip. In the LTNE model, the temperature in each constituent phase is governed by the heat equation with heat exchange between the two phases counted as a heat source or sink. Besides the LTNE model, a matricity-based effective thermal conductivity model for IPCs is also used to compute the temperature distribution in the composite. The thermal stress, thermal stress intensity factor, and the critical thermal shock causing crack propagation are determined by using the temperature fields of both LTNE and the matricity models. An Al2O3-aluminum IPC is considered in the numerical analysis. It is shown that the LTNE model predicts a lower peak thermal stress intensity factor and higher critical thermal shocks for initiating crack propagation than those predicted by the conventional theory of homogenized composites described by the effective properties.