Inelastic analysis of granular interfaces via computational contact homogenization

The macroscale response of granular contact interfaces is investigated. In order to circumvent the difficulties associated with a direct resolution of such heterogeneous contact problems, where highly mobile particles residing between a deformable body and a rigid surface govern the microscale dynamics, a space–time contact homogenization methodology is developed. The overall approach is based on a separation of spatial as well as temporal scales and proposes an idealized purely frictional macroscale response. The induced macroscale dissipation is directly associated with the microscale dissipation mechanisms due to (i) an inelastic constitutive response for the boundary layer of the deformable body and (ii) frictional interaction among the components of the three‐body contact system. The consequences of a viscoelastic boundary layer that sustains damage due to highly localized deformation in the vicinity of the particles are investigated extensively within a fully nonlinear computational setting that accounts for incompressibility. The effective coefficient of friction that is induced by the homogenization methodology as the fundamental macroscale observable is found to be of a non‐Amontons as well as a non‐Coulomb type. The proposed analysis framework is amenable to a multiscale implementation within a coupled micro–macro approach and yields insight into the macroscopic dynamics of similar heterogeneous interfaces with varying degrees of mobility associated with the roughness features. Copyright © 2010 John Wiley & Sons, Ltd.