Nonclassical Thermomechanics of Granular Materials

The description of the flow of a granular material with rigid grains requires a combination of suggestions from both fluid and solid mechanics owing to the fact that the material has an essentially fluid-like behavior, but it can also be heaped and, moreover, its bulk compressibility depends on the initial voids distribution. Hence, for the study of this medium, a continuum theory is proposed here that follows mainly from the thermomechanical approach of Dunn and Serrin, but also takes into account characteristic postulates about flows of granular materials with inelastic granules; in particular we obtain the following result: the stress tensor, the kinetic energy and the heat flux must be additively decomposed. Moreover, the balance of angular momentum is given here in a more general form suggested by the mechanical nature of the ‘interstitial working’ of Dunn and Serrin.