Propagation and Localization of Longitudinal Thermoelastic Waves in Layered Structures

Abstract

Based on the generalized dynamical theory of thermoelasticity, a transfer matrix formulation including the second sound effect is developed for longitudinal wave component propagation in a thermoelastic layer. The second sound effect is included to eliminate the thermal wave travelling with infinite velocity as predicted by the diffusion heat transfer model. Using this formulation and the periodic systems framework, the attenuation and propagation properties of one-dimensional thermoelastic waves in both continuum and layered structures are studied. Strong localization of thermal waves predicted by the analysis in the transformed domain is demonstrated in the time-spacial domain by an FFT-based transient analysis. Also, a perturbation analysis for identifying leading terms in thermal attenuation is performed, and the role of the thermal elastic coupling term in attenuation is determined. The attenuation factor, defined as the real part of the propagation constant, is obtained in thermoelastic solids. The reflection and transmission coefficients between half-spaces are also calculated to evaluate the potential practical use of the approach in thermal-based nondestructive testing. [S0739-3717(00)00403-7]