ABSTRACT
Thermodynamics is a very important subject in the study of the theory of thermoelasticity. The state of a thermodynamic system is defined by a number of independent variables. The principle of energy conservation and the second law of thermodynamics are introduced. The Helmholtz free energy and the Gibbs thermodynamic potential are derived to discuss the thermodynamics of deformation of the body. The heat conduction equation and the equation of motion are considered from the viewpoint of the thermodynamics of deformation of the elastic body. The variational equations of the coupled dynamical thermoelasticity of 3D bodies are formulated from the basic principles. Thermoelasticity is concerned with equilibrium of the bodies subjected to mechanical and thermal loads, and which can be treated as thermodynamic systems. In thermodynamics a complete set of state parameters includes four parameters such as the absolute temperature and spatial coordinates. There are two categories of the thermodynamic processes, reversible and irreversible processes.
