Effect mechanism of contact sliding state on rheological properties of dense granular inertial flow

Abstract

The contact sliding state of particles within a granular system can significantly affect the macroscopic rheological behaviors. Here, the whole contact network of a dense granular inertial flow is partitioned into nonsliding and sliding subnetworks. Discrete element method simulations are employed to comprehensively study the microstructure characteristics, anisotropies, and contributions of subnetworks, by virtue of a unified expression of stress-force-fabric relationship. In terms of the microstructure characteristics, the nonsliding subnetwork is segmented by the sliding subnetwork, which reduces the whole system's stability. All the individual anisotropic parameters of subnetworks contribute positively to the whole network's shear strength, except the anisotropy in the sliding subnetwork's normal contact force. The nonsliding subnetwork always makes more contribution to the shear strength; however, its contribution weight decreases with flow rate increasing. Additionally, the difference and complementarity in stability between subnetworks make the whole network maintain a dynamic balance between collapse and reconstruction. • The whole contact network is partitioned into sliding and nonsliding subnetworks. • The contributions of subnetworks are unified by stress-force-fabric relationship. • The nonsliding subnetwork dominates both load-bearing capacity and shear strength. • Anisotropy in the sliding subnetwork's normal contact force contributes negatively. • The difference and complementarity in stability between subnetworks are revealed.