Numerical study of a thin layer of cohesive particles under plane shearing

This article presents the development of 3D computer simulations using the discrete element method to study solid third body flows (particles trapped in a contact between two bodies). The configuration chosen here is plane shearing in which a thin layer of particles is sheared between two walls. A confining pressure is imposed on the upper wall and a horizontal velocity is imposed on the lower wall, thereby shearing the granular media between the two walls. The rheology of this granular media is studied and a transformation from a quasi-fluid behaviour to quasi-solid behaviour is highlighted. This rheology considerably affects the macroscopic friction coefficient, which increases with adhesion and then decreases. These variations are linked to the different states of the granular media. This work emphasises the complexity of the behaviour of the interfacial particle layer. Consequently, the friction coefficient measured when two pieces are in contact may greatly depend on the behaviour of this particle layer. (c) 2005 Elsevier B.V. All rights reserved.