An internal-variable theory of thermo-viscoelastic constitutive relations at finite strain
Based on the nonequilibrium thermodynamic theory, the authors propose a new thermo-viscoelastic relation at finite strain. Under the assumption that the specific heat at a fixed strain and fixed internal variables can be regarded as constant values, the authors derive a new expression for the free energy which decouples mechanical and thermal effects. Through an analysis of mesoscopic deformation mechanism of solid polymers, a set of internal variables is introduced, and an internal-variable constitutive theory in thermo-viscoelasticity at finite strain is formulated. An explicit thermo-viscoelastic constitutive relation is obtained for solid polymers in the case when their molecular network has a randomly oriented distribution function in the reference configuration. Moreover, the authors also discuss a relationship between relaxation time and temperature. The usual viscoelastic constitutive theory is only a linear approximation of the present theory.
thermo-viscoelastic constitutive relations
scientific article; zbMATH DE number 1531258