A POROUS-MEDIA MODEL FOR THIN-FILM LUBRICATION

A rheological model has been developed which can be applied to boundar y lubrication. The model is applicable to thin films in which the mole cular length scale is the same order as the film thickness. The micro structure is simulated by porous layers attached to the contact surfac es. The model contains three material properties: (I) viscosity, (2) t he thickness of the porous layer, and (3) a porosity parameter. A modi fied Reynolds equation is developed. Behavior in two types of contacts is calculated: squeezing flow between crossed cylinders (Chan and Hor n's, 1985 drainage experiment) and a one-dimensional converging wedge contact. The effect of the layer thickness parameter is to increase th e load and reduce the friction coefficient. Increasing the porosity pa rameter value tends to reduce the magnitude of the load increase.