Application of a generalized heat equation to ultra-fast processes in viscoanelastic isotropic medium

Abstract Using a classical irreversible thermodynamics of internal variables (CIT-IV) with V. Ciancio’s procedure, viscous-inelastic flow relations have been derived by generalizing the Duhamel-Neumann law for ordinary thermoelastic phenomena in isotropic media and the relations for elastic media and for Maxwell, Jeffreys and Poynting-Thomson bodies. In literature, Fourier and Maxwell-Cattaneo-Vernotte’s (MCV) heat transport equations are based on hypothesis that lack physical confirmation while the V.Ciancio model obtains both mathematical and physical applications. In this context, through the simple description of the ultra-fast process of energy transmission from a laser source to metal film, using the principles of thermodynamics, the heat equation is derived in the case of isotropic viscoanelastic media subject to constant strain. The solution, obtained numerically with the finite element method, not only highlights the physical significance of the phenomenological coefficients, but also specifies the limits of the previous theories of the MCV.