États de compacité maximale pour les mélanges binaires de grains sphériques : étude par simulation numérique

Jean-Noël Roux (1) , François Chevoir (2) , Fabrice Toussaint (3)

1 navier umr 8205 - Laboratoire Navier
2 Rhéophysique
3 Lafarge LCR Lyon - Lafarge Centre de Recherche [Lyon]

Disordered assemblies with maximum packing fraction are studied by discrete element numerical simulation for monodisperse or bidisperse spherical particles, the diameter ratio being set at three. A maximum packing fraction value corresponds to an equilibrium state under isotropic loading of rigid frictionless particles. A statistical study of size effects enables one to evaluate, in the limit of large systems, the maximum packing fractions of both monodisperse assemblies, for which the conventional value 0.639 is retrieved, and bidisperse ones, for two distinct values of the coarse particle volume fraction. An enduring initial assembling step in which agitated grains interact through collisions induces an increase in the final packing fraction due to crystalline order nucleation for a monodisperse system or to a gradual segregation for a binary mixture. Albeit slow and moderate in a number of practical situations, this effect leads to a definition of the random close packing state, as the one obtained with frictionless rigid grains under an isotropic pressure in the limit of fast assembling processes. A few potential extensions to this preliminary study are suggested.

Mots clés: granular material; solid fraction; binary mixture; random close packing

Domaines: Science des matériaux [cond-mat.mtrl-sci]; Mécanique des matériaux [physics.class-ph]; Mécanique des matériaux [physics.class-ph]; Systèmes désordonnés et réseaux de neurones [cond-mat.dis-nn]

Jean-Noël Roux, François Chevoir, Fabrice Toussaint. États de compacité maximale pour les mélanges binaires de grains sphériques : étude par simulation numérique. Bulletin des Laboratoires des Ponts et Chaussées, 2007, 268-269, pp. 141-152. ⟨hal-00355271⟩