Fracture analysis of a non-homogeneous coating structure with dual interfaces under thermal shock

Abstract

To solve the thermal fracture problem of non-homogeneous coating structure (NCS) with dual interfaces under strong transient thermal loading, this paper proposes a method to extract fracture parameters by combining the Newmark method and the transient interaction energy integral method (IEIM). The strong transient temperature and the transient thermal stress intensity factors (TSIFs) of NCS with dual interfaces under strong transient thermal load can be obtained through the proposed method. The interfaces are divided into an ideal interface, weak interface, and strong interface according to the continuity of the material parameters of NCS at the interface. Firstly, the influences of Young's modulus, thermal relaxation time, thermal expansion coefficient, and density continuity on TSIFs at strong and weak interfaces are studied. Then, the crack growth laws under thermal shock at the strong and weak interfaces are analyzed. Finally, according to the influence of the coating thickness on TSIFs, the optimal thickness ratio of the dual interface structure ranging is selected to minimize the likelihood of thermal fracture. This work can be used for the thermal design, evaluation, and engineering applications of NCS.