On the development of a Reynolds equation for air bearings with contact

In hard-disk drives, the air bearing that separates the slider and the disk provides the necessary lubrication that allows a reliable operation. However, due to the small height of the air bearing, intermittent contact between the slider and the disk can create a wear problem. An important step in the development of a comprehensive wear model is to incorporate an air bearing model that can provide accurate estimates of the air pressure when contact between slider and disk occurs. The purpose of this research is therefore to evaluate existing air bearing models under contact conditions and to provide an air bearing model appropriate for contact.; In the process of evaluating current air bearing models we develop some two dimensional transient exact analytical solutions of the no slip and first-order slip Reynolds equations. Thereafter, we perform a local asymptotic analysis and a numerical analysis of some of the existing Reynolds equations under conforming contact. The results show that the no slip and first-order slip Reynolds equations are inappropriate to model air bearings with contact, since they predict infinite contact pressures. We next use Stokes equations to model Taylor's scraping plane problem with a 90{dollar}spcirc{dollar} angle between contacting plates. This part of the study allows for a proposed modification to Maxwell's theory of slip. The analytical and numerical results show that for the 90{dollar}spcirc{dollar} contact geometry, the modified Maxwell slip produces a bounded contact pressure. Stokes equations and Reynolds equation are then used, together with the modified Maxwell slip boundary condition to model an incompressible bearing in contact. For this bearing, both Stokes and Reynolds equations produce bounded contact pressures, and the pressure predictions of these equations are found to be very similar. Finally, the development of the incompressible Reynolds equation with modified Maxwell slip reveals that the second-order slip and 1.5-order slip incompressible Reynolds equations can also produce bounded contact pressures.