Harmonic waves in thermoviscoelastic solids

The constitutive properties and time-harmonic wave propagation in thermoviscoelastic solids are investigated through the energy flux. First the dissipative character of the model is characterized by requiring that the divergence of the energy flux vector be non-positive. The attention is then restricted to planarly stratified solids and the governing equations are shown to satisfy a first-order system of the Stroh-form. The corresponding scalar energy flux is examined and shown to satisfy a decay property which, thanks to a previous result, provides existence and uniqueness for the reflection-transmission process generated by a layer. The required definiteness property of an appropriate matrix is shown to hold in particular cases.