Elastohydrodynamic Lubrication of Squeeze Films : Part 2, Two spherical bodies lubricated with grease

Abstract

In this paper, an elastohydrodynamic squeeze problem between two spherical bodies lubricated with grease is studied. In this analysis, grease is assumed to be a Bingham solid whose plastic viscosity and yield stress depend on the pressure, and the time-dependent elastohydrodynamic equation for a Bingham solid is solved by the same method presented in the author's previous paper. It is discussed how the core formation, which is the inherent property of a Bingham flow, affects the film profile and the load capacity. In the experiment, a spherical body is dropped onto a lubricated optical flat and the film profiles are measured using the interferometric method and photographed by a highs peed cinecamera. It is discussed, using grease and gear oil, how the various lubricants affect the film profile. analytical results and experimental ones are compared.