LUBRICATION OF A CYLINDRICAL SYNOVIAL JOINT CONSIDERING ROLLING MOTION AND ELASTIC INCOMPRESSIBLE CARTILAGE

In the analysis of lubrication of rolling cylinders with low modulus c oatings, attention is drawn to elastic incompressible layers. The cons trained column model (a simplified model where layer compression is as sumed proportional to fluid pressure) fails for the Poisson ratio nu o f the layers close to 0.5. An approximate lubrication model is propose d for nu = 0.5 and highly deformed coatings, i.e. for the low ratio of elastic layer thickness to fluid film length. This model does not res ult in a rigid differential equation for high loading as is the case w ith the constrained column model. The model is applied to the rolling motion of the human ankle joint.