A kinetic elasto-plastic model exhibiting viscosity bifurcation in soft glassy materials

Abstract

A kinetic elasto-plastic model of the dynamics of a flowing jammed material is proposed, supplemented with a phenomenological equation describing the coupling of the flow and the structure of the fluid. Coarse graining these equations yields a non-local constitutive law for the flow, with the introduction of the number of plastic events per unit time, called the fluidity, as a key dynamical parameter. Above a given threshold, the weakening of the structure caused by the flow induces a macroscopic phase separation that causes viscosity bifurcation.