A Crack Parallel to the Interface Between a Functionally Graded Thermal Barrier Coating and a Homogeneous Elastic Substrate Under Transient Thermal Loading

Abstract

In this paper, the fracture problem of a functionally graded thermal barrier coating (FGTBC) containing a crack parallel to the interface between the FGTBC and a homogeneous substrate is considered. The problem is solved for the laminate that is suddenly heated from the upper surface of the FGTBC. The bottom surface of the homogeneous substrate is maintained at the initial temperature. The crack faces are supposed to be completely insulated. Material properties are assumed to be exponentially dependent on the distance from the interface. By using both the Laplace and Fourier transforms, the thermo-mechanical fracture problem is reduced to a singular integral equation and a system of singular integral equations which are solved numerically. The stress intensity factors of the crack are computed and presented as a function of the normalized time for the various values of the nonhomogeneous and geometric parameters.