Shear strength, force distributions and friction mobilization in sheared packings composed of angular particles

Emilien Azéma (1, 2) , Nicolas Estrada (3) , Farhang Radjai (1, 2)

1 PMMG - Physique et Mécanique des Milieux Granulaires
2 LMGC - Laboratoire de Mécanique et Génie Civil
3 Departamento de Ingeniería Civil y Ambiental - CeiBA Complex Systems Research Center, Universidad de Los Andes

In this paper, we explore the effect of particle shape angularity on the mechanical behavior of sheared granular packings. A first series of contact dynamics simulations is performed in 2D with regular polygons with an increasing number of sides ranging from 3 (triangles) to 60. Then, in order to approach "idealized" angular particles, a second series of simulations is performed in 3D with irregular polyhedra with the number of faces ranging from 8 (octahedron-like) to 596. A counterintuitive finding is that the shear strength increases with angularity up to a maximum value and saturates as the particles become more angular (below 6 sides in 2D and 46 faces in 3D). A micromechanical analysis of force and contact orientations, all enhanced by face-face and face-side contacts, reveals that this increase is due to an increase of both contact and force anisotropies, and the saturation for higher angularities is a consequence of a rapid fall-off of the contact and normal force anisotropies compensated by an increase of the tangential force anisotropy.

Mots clés: Polyhedral particles; texture; shear behavior; contact dynamic method

Domaines: Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]; Matériaux et structures en mécanique [physics.class-ph]; Matériaux et structures en mécanique [physics.class-ph]

Emilien Azéma, Nicolas Estrada, Farhang Radjai. Shear strength, force distributions and friction mobilization in sheared packings composed of angular particles. Powder and Grains 2013, 2013, Sydney, Australia. pp.511-514. ⟨hal-00842744⟩