Plane waves in nonlocal viscothermoelastic medium with temperature-dependent properties under three-phase-lag theory.

The present investigation deals with the study of propagation of plane waves in a homogeneous, isotropic, nonlocal viscothermoelastic half space with temperature-dependent properties in the context of three-phase-lag (TPL) model. The Kelvin–Voigt model of linear viscoelasticity is employed to describe the viscoelastic nature of isotropic material. A set of coupled longitudinal waves and one independent transverse wave are found to travel with distinct speeds in the medium. Reflection coefficients and energy ratios of various reflected waves are presented when (1) a set of coupled longitudinal waves is made incident and (2) a transverse wave is made incident. The results for partition of the energy for various values of the angle of incidence are computed numerically and presented graphically for copper material. It has been verified that there is no dissipation of energy at the boundary surface during reflection. The effects of nonlocal parameter, viscosity and temperature dependent properties on reflection coefficients are depicted graphically. A comparison between the TPL model and GNIII model is also presented by different characteristics of wave propagation like phase velocity and reflection coefficients. [ABSTRACT FROM AUTHOR]