Fluid-Film Lubrication Regimes Revisited

Dimensionless film-thickness equations are provided for four fluid-film lubrication regimes found for nonconformal surfaces. Side-leakage effects are present in the equations. These regimes are isoviscous-rigid; piezoviscous-rigid, isoviscous-elastic, or soft EHL; and piezoviscous-elastic, or hard EHL. The influence or lack of influence of elastic and viscous effects is a factor that distinguishes these regimes. The film-thickness equation for the respected regimes come from earlier theoretical studies. Results are presented as a map of the lubrication regimes, with film thickness contours on a log-log grid of the viscosity and elasticity parameters for four values of the ellipticity parameter.