Experimental Research on Force Transmission of Dense Granular Assembly Under Shearing in Taylor–Couette Geometry

Abstract

Considering the difficulties in experimental research on journal bearings under granular lubrication, we have designed and developed a Taylor–Couette geometry tester to study granule behavior under shearing. Surface structure, granularity, granular material, filling amount, gap eccentricity, and granular distribution are considered in our experiments. The measured torque, which is transmitted from the inner to the outer cylinder, reveals the effect of these input parameters on force transmission behavior. Results show that a rough surface, a high filling amount, a heavy material, and a eccentricity geometry increase the measured torque. The effects of granularity, cylinder–granule slip, granule distribution, and torque mutation are discussed as well. Force transmission is directly affected by cylinder–granule contact and force transmission path in granule assembly. The cylinder and granule contact occurs through the cylinder–granule slip and granular collision. The force transmission path in the granule assembly is dependent on the formation or breakage of the arch and the force chain, which is closely related to flow state. In the article, some direct links between the experimental results and the optimization of an actual granular lubricated journal bearing are provided.