Continuum stress characteristics inside shear bands

Abstract

A defining aspect of the large strain, fully developed plastic flow regime, or "critical state", for granular materials undergoing localized failure is the continual growth of new force chains amidst collapse by buckling of old force chains in the persistent shear band. This paper explores the constitutive response inside shear bands, in particular, the birth-death evolution of force chains for a Cosserat medium, whereby closure relationships for stresses and couple stresses satisfy the isostatic condition, albeit in a spatiotemporal average sense only. The continuum stress-equilibrium relations comprise a hyperbolic system of partial differential equations giving rise to characteristic line..