Basic theorems and wave propagation in a piezothermoelastic medium with dual phase lag

The basic governing equations for an anisotropic piezothermoelastic solid with dual phase lag are presented and used to study the problem. Some basic theorems like variational principle, uniqueness theorem and theorem of reciprocity are established for the assumed model. Also, we characterize an alternative formulation of the mixed initial boundary value problem. These theorems are also summarized for a special case of orthotropic piezothermoelastic solid with dual phase lag. We formulated the plane wave propagation in an orthotropic piezothermoelastic solid with dual-phase-lag model. The non-trivial solution of the system is insured by a quartic equation whose roots represent the complex velocities of four attenuating waves in the medium. Various characteristics of the waves like phase velocity, attenuation quality factor, specific heat loss and penetration depth are computed numerically and shown graphically for three different models with the direction of propagation in three-dimensional space. Some special cases are also deduced from the present investigation. (author)