Title: Size Dependence of the Yield Threshold in Dense Granular Materials

Author (Poster): David Henann, Brown University

Abstract:

Yield of dense granular materials is typically modeled by local, pressure-dependent criteria, in which yield at a point is assessed based only on the state of stress at that point. However, nonlocal effects lead to phenomena that cannot be captured with local yield conditions. In a widely studied example, flows of thin layers of grains down an inclined surface exhibit a size effect whereby thinner layers require more tilt to flow. In this study, we explore the configurational generality of this size-dependent yield phenomenon by considering two additional examples of inhomogeneous flow - planar shear with gravity and vertical chute flow - through two-dimensional discrete element method calculations. We show that the nonlocal granular fluidity model - a nonlocal continuum model for dense granular flow - is capable of capturing the size-dependence of the yield threshold in all configurations considered.