VISCOPLASTIC FLOW OF PLANAR GRANULAR-MATERIALS

A rate-dependent constitutive model for the viscoplastic flow of granular materials is presented. The kinematics is based on the rate-dependent sliding of layers of granules, which results in overall dilatant shearing of the granular medium. Stress-induced anisotropy in the elastic and inelastic instantaneous material response is incorporated. Typical results for monotonic and cyclic loading are presented for illustration, and are shown to accurately correspond to actual observations. Results from this model for various rate-sensitivity parameters at strain rates are compared with those of the rate-independent model.