Stress distribution of faceted particles in a silo after its partial discharge

Abstract

Abstract. We present experimental and numerical results of the effect that a partial discharge has on the morphological and micro-mechanical properties of non-spherical, convex particles in a silo. The comparison of the particle orientation after filling the silo and its subsequent partial discharge reveals important shearinduced orientation, which affects stress propagation. For elongated particles, the flow induces an increase in the packing disorder which leads to a reduction of the vertical stress propagation developed during the deposit generated prior to the partial discharge. For square particles, the flow favors particle alignment with the lateral walls promoting a behavior opposite to the one of the elongated particles: vertical force transmission, parallel to gravity, is induced. Hence, for elongated particles the flow developed during the partial discharge of the silo leads to force saturation with depth whereas for squares the flow induces hindering of the force saturation observed during the silo filling.

Nonlinear effects of particle shape angularity in sheared granular media

“…This shows that the variation of the shear strength is mostly governed by the contribution of side-side contacts, even if their proportion is low. This profound effect of faceted grain shapes on stress transmission has been previously shown, both experimentally and numerically [17][18][19][20].…”

“…These shape characteristics strongly affect the rheology and texture of granular materials. This has been recently evidenced by a number of numerical and experimental studies carried out using angular particles [1][2][3][4][5][6][7][8][9][10][11][12] and by a number of investigations that have focused on other important characteristics such as elongation [13][14][15][16][17][18][19][20] or non-convexity [21,22]. The existing research results suggest that the effect of shape parameters is often nonlinear and counterintuitive as in the case of the unmonotonic relation between the elongation of the particles and the packing fraction [13,14,18].…”

Granular materials composed of shape-anisotropic grains

“…Elongated grains tend to align horizontally and the stress is transmitted mainly from top to bottom, revealing an asymmetric distribution of local stress [74,75]. Kanzaki et al analyzed how this stress distribution changes if the two-dimensional container (silo) is partially discharged [76] through an orifice at the bottom. As we will see in section III B, the flow pattern for elongated grains is different from that of circular ones, and it involves regions with strong velocity gradients (shear zones) where particles are reoriented by the flow.…”

Particle alignment and clustering in sheared granular materials composed of platy particles

“…The grain shape considerably affects the quasi-static mechanical behavior of granular materials [4][5][6][7][8][9]14,33]. There is a multitude of potential particle morphologies and recently a wide range of nontrivial effects were -systematically -reported by means of discrete numerical simulations [10][11][12][13][14][15][16][17]19]. Indeed, one of the major interests of discrete approach is to make it possible to control precisely the shape of the particles with continuously-variables parameters.…”