THERMOELASTICITY PROBLEM FOR A MULTILAYER COATING-SUBSTRATE ASSEMBLY IRRADIATED BY A LASER BEAM

摘要

An analytical solution of a two-dimensional thermoelasticity problem is determined for a thin coating attached to a substrate. The coating is treated as a stratified multilayer structure composed of layers with varying thermophysical and optical characteristics. The developed mathematical procedure of solution is based on expansion of Laplace and Hankel transforms of temperature, displacement and strain distributions in series of small parameter which is equal to the ratio of a coating thickness to a laser beam radius. Expressions for determination of the two-dimensional nonstationary temperature, strain and stress distributions in a multilayer assembly are derived in a closed analytical form which can be used for development of an algorithm of laser photothermal method for detection of failures in the multilayer coating-substrate systems. [References: 6]