Shear rate and pressure effects on boundary slippage in highly stressed contacts

Boundary slippage has been well confirmed using micro/nano measuring technologies and molecular-dynamic simulations. However, the characteristics of slip behaviour are still open for discussion due to their various behaviors under different conditions. This paper focuses on the boundary slippage under EHL conditions and its dependence on the shear rate and pressure. By tracing the movement of entrapped high molecular polymeric lubricants, boundary slippage was inferred. The slip length was measured under different conditions. The results showed that slip length varies exponentially with shear rate, indicting a nonlinear relationship. With pressure increasing, the slip length increased linearly in double logarithmic coordinates. (C) 2012 Elsevier Ltd. All rights reserved.