On the nonlinear Maxwell-type defining equations for describing the motions of polymer liquids (Q1080299)

The problem of using nonlinear Maxwell equations containing elastic deformation as the intermediate parameter, to approximate experimental data on the motion of polymer liquids under arbitrary elastic deformations, is studied. The data used concern the simple shear, uniaxial tension and pure shear. The form of the dependence of the free energy and rate of irreversible deformation on the elastic deformation is expressed in specific terms. It is assumed that in the course of the deformation, directional phenomena such as crystallization, and mechanical destruction play a negligible part. We use an approach in which the general form of Maxwell's equations is obtained within the framework of quasilinear non-equilibrium thermodynamics under the assumption that the locally equilibrium state of the medium is non-linearly elastic. The drawbacks apparent in the description of the experimental facts, based on specific equations, are noted and a simple method for overcoming them is proposed.