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Abstract
The distribution probability of contact force, force chain evolution law, dynamic states, and the force chain distribution characteristics for granular flow lubrication are researched. In order to study the above contents, a granular flow lubrication model of parallel sliding friction pairs basing on the discrete element method is built. The results show that the normal contact force, tangential contact force, and total contact force are all consistent with the power law, and the granular flow is mainly influenced by the normal contact force. When the lower friction pair speed increases from 1.5, 4.5, to 15 m/s, the dynamic behavior of granules can transform into four flow states: a jamming state, quasistatic flow, slow flow, and rapid flow. Under the four flow states, the magnitude of the total force chains is higher in the jamming, quasistatic flow, and slow flow state but lower in the rapid flow state. In the process of the granule dynamic flow state changing from a rapid flow state, to a slow flow state, to a quasistatic flow state, the number of weak force chains decrease notably, whereas the number of strong force chains and super strong force chains increases; in addition, the flow speed of the granular lubrication medium and the deconstruction and reconstruction speed of the force chains will obviously slow down.