Dynamic sliding friction and similarity with Stokes׳ law

This study investigated the dynamic sliding friction of polyurethane (PU) rubber samples on an inclined smooth transparent polymethylmethacrylate (PMMA) surface with a thin layer of silicone oil. The sliding velocity increased during the initial stages of sliding and approached a constant value toward the latter stages. To describe the changes in velocity observed, the present study developed an analytical model based on Couette flow with no pressure gradient and indicated that the model could predict important changes in velocity. These findings suggest that dynamic friction force is dependent on both the sliding velocity and the contact area, and that the behavior is similar to that given by Stokes׳ law, which describes the falling velocity of a particle in a viscous fluid.