Effects of Non-Newtonian Couple Stresses on the Dynamic Characteristics of Wide Rayleigh Step Slider Bearings

Abstract

Based upon the micro-continuum theory developed by Stokes (1966), the present study investigates the non-Newtonian effects of couple stresses upon the dynamic characteristics of wide parabolic-shaped slider bearings. To account for the couple stress effects resulting from a Newtonian lubricant blended with various additives, the non- Newtonian dynamic Reynolds-type equation is derived using the Stokes motion equations together with the continuity equation. A closed-form solution for the bearing characteristics is obtained for engineering applications. Comparing with the parabolic-film Newtonian-lubricant case, the effects of couple stresses provide an increase in the dynamic stiffness and damping coefficients. Comparing with the inclinedplane bearings with couple stress fluids by Lin et al. (2003), the parabolic-film slider bearings signifies an improvement in the dynamic stiffness and dynamic characteristics; the improvement of bearing dynamics is more pronounced for lower squeezing-film heights and larger geometrical parameters and non-Newtonian couple stress parameters. The results of the present study provide engineers useful information in bearing selection and designing.