Using a coupled FEM-DEM method to study the nonlinear phenomena of third-body behavior

Abstract

Third-body lubrication is widely applied in the design of mechanical frictional pair, but the relation between the lubrication performance and third-body rheology is hardly focused on. In this paper, the behavior of two plates shearing granular third-body is modeled by a coupled FEM-DEM method to study the nonlinear phenomena during this process. The upper plate is modeled by FEM, while the third-body and lower plate are modeled by DEM. During the simulation, the upper plate compresses the granular third-body at a certain pressure. Then, the lower plate shears at a constant speed. The fluctuations of friction force and dilatancy phenomenon of clearance between two plates, which show strong nonlinearity over time, are studied over different external loads, shearing speeds, and elastic moduli. The nonlinear distributions of averaged stress and velocity across the height of third-body are also studied to further reveal the relation between the nonlinear phenomena and the discreteness of third-body. The perspective of the paper is that the coupled FEM-DEM method can elucidate the nonlinear nature of third-body by efficiently processing both the third-body rheology and first-body deformation.