Rearrangements and dilatancy for sheared dense materials.

Constitutive equations are proposed for dense materials, based on the identification of two types of free-volume activated rearrangements associated with shear and compaction. Two situations are studied: the case of an amorphous solid in a stress-strain test, and the case of a lubricant in tribology test. Varying parameters, strain softening, shear thinning, and stick-slip motion can be observed.