A benchmark for particle shape dependence

Gaël Combe (1, 2) , Cécile Nouguier-Lehon (3) , Emilien Azéma (4) , Krzysztof Szarf (1) , Baptiste Saint-Cyr (4) , Marie Chaze (3) , Farhang Radjai (4) , Pascal Villard (1, 2) , Jean-Yves Delenne (5) , Vincent Richefeu (1, 2) , Philippe Sornay (6) , Charles Voivret (7)

1 3SR - Laboratoire sols, solides, structures - risques [Grenoble]
2 GéoMécanique
3 LTDS - Laboratoire de Tribologie et Dynamique des Systèmes
4 PMMG - Physique et Mécanique des Milieux Granulaires
5 UMR IATE - Ingénierie des Agro-polymères et Technologies Émergentes
6 LCU - Laboratoire des Combustibles Uranium
7 R&D - SNCF - Département recherche et développements

Particle shape is a major parameter for the space-filling and strength properties of granular materials. For a systematic investigation of shape effect, a numerical benchmark test was set up within a collaborative group using different numerical methods and particles of various shape characteristics such as elongation, angularity and nonconvexity. Extensive 2D shear simulations were performed in this framework and the shear strength and packing fraction were compared for different shapes.We show that the results may be analyzed in terms of a low-order shape parameter h describing the degree of distortion from a perfectly circular shape. In particular, the shear strength is an increasing function of h with nearly the same trend for all shapes, the differences being of second order compared to h. We also observe a nontrivial behavior of packing fraction which, for all our simulated shapes, increases with h from the random close packing fraction for disks, reaches a peak considerably higher than that for disks, and subsequently declines as h is further increased. Finally, the analysis of contact forces for the same value of h leads to very similar statistics regardless of our specific particle shapes.

Mots clés: Polygones; Clumps; Shear Test; Contact Dynamic; Shape Dependence; Molecular Dynamic; Granular Media

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

Gaël Combe, Cécile Nouguier-Lehon, Emilien Azéma, Krzysztof Szarf, Baptiste Saint-Cyr, et al.. A benchmark for particle shape dependence. Powder and Grains 2013, 2013, Sydney, Australia. pp.883-886, ⟨10.1063/1.4812073⟩. ⟨hal-00842754⟩