Surface Roughness Influence on the Dynamic Performance of Rayleigh Step Bearing Lubricated with Couplestress Fluid

Abstract

In the present paper, we have analyzed the surface roughness influence on the dynamic performance of Rayleigh step bearing by taking the squeezing action. The non-Newtonian lubricant in the film region considered is a couplestress fluid. A stochastic random variable with a non-zero mean, variance and skewness characterizes the roughness. The improved averaged Reynolds type equation is obtained using constitutive Stoke’s equations for couple stress fluid and stochastic surface roughness theory. For volume flow rate, steady-state characteristics and dynamic characteristics are derived in closed-form expression and are solved numerically by Simpson rule using Mathematica software. The non-Newtonian couplestress fluid enhances (diminishes) the steady load carrying capacity, the dynamic stiffness, and the dynamic damping coefficients, also a decrease (increase) in the volume flow rate is required for negatively (positively) skewed surface roughness in accordance with the Newtonian case. The relative percentage increase in bearing characteristics is studied. The results are considered with that of the smooth case.