ABSTRACT
Some of the features assigned to the particles making up a granular film are that they are nearly spherical in shape, are free of intergranular cohesion, and the spacings between the particles are small compared to their diameter. There is very little direct experimental data on the lubrication capacity of granular films, if for no other reason than the whole field is relatively new. One of the basic questions, and one that is central to the nature of granular lubrication, is whether such a layer can produce load-8upporting pressures. One of the items discussed in the analysis by Haff is that a granular layer distinguishes between a smooth boundary and one composed of granules identical to the film itself. The top disk was restrained by a torque arm to measure friction; it is also free to move vertically to accommodate any expansion or contraction of the granular film during operation.
