Optimum shape design for surface of a porous slider bearing lubricated with couple stress fluid

Porous-bearing performance can significantly benefit from optimally designing the shape of the bearing. The present paper introduces an approach for designing the optimum shape of a slider bearing using an inverse method. The proposed approach utilises a sequential quadratic programming algorithm to minimise friction subject to load and centre of pressure requirements specified by the designer. Bearing characteristics, such as friction, load and centre of pressure, are obtained by solving a modified Reynolds-type equation numerically using the finite difference method. The modified Reynolds equation is derived on the basis of Stokes' microcontinuum theory of couple stress fluids, which is used to study non-Newtonian lubricants. Results show that the optimisation approach reduces the coefficient of friction. In addition, the dimensionless slip parameter is shown to be the most significant parameter affecting optimal friction. Copyright © 2008 John Wiley & Sons, Ltd.