Thermodynamic relaxation. A contribution to constitutive laws for complex materials.

In order to establish constitutive laws for materials, we present in this paper a point of view based on thermodynamic relaxation laking into account internal variables, in accordance with previous presentations. The originality of this work lies essentially on the fact that we use a normal mode description near the equilibrium and that the corresponding distribution law is built on fluctuation concepts. Another important key is the introduction of non linear couplings between normal modes far From the equilibrium. The physical meaning of these effects is related to the kinetic activation state representation of the relaxation times. Various applications chosen in the field of mechanical properties are proposed here.