NON-LINEAR RHEOLOGICAL MODEL OF MATERIALS BASED ON IRREVERSIBLE THERMODYNAMICS.

This paper is concerned with the influence of internal friction on the rheological features of steels below their yield strength in a stationary temperature field. Developments in materials science are adopted in the analysis. The thermodynamics of irreversible processes to derive a stress-strain-temperature constitutive equation for isotropic, non-linear viscoelastic media is used. The constitutive equation is expressed as a differential equation with material parameters. The equation can be used to describe the main rheological features of steels, such as stress relaxation, creep, loop hysteresis, and dependence of modulus on velocity of loading.