Coupled thermodynamic orhogonality in non-linear models of type-III thermoelasticity

Abstract

The present study is devoted to a derivation of non-linear constitutive equations for the non-linear Green-Naghdi type-IIIthermoelastic model on the basis of the principle of thermodynamic (or thermomechanical) orthogonality.The latter was proposed by Ziegler as an extention to the Onsager linearirreversible thermodynamics. It states that the irreversible constituent parts of thermodynamic currents (velocities)are orthogonal to the convex dissipation potential level surface in the space of thermodynamic forces for anyprocess of heat propagation in a solid. Non-linear constitutive laws of the heat propagationcomplying with the principle of thermomechanical orthogonality are obtained and discussed.

Keywords

• thermoelasticity
• maximum principle
• irreversible process
• thermodynamic orthogonality
• thermodynamic force
• thermodynamic flux
• constitutive law