Abstract
This study presents an analysis of the contact of a rippled rigid impermeable indenter against a cartilage layer, which represents a first simulation of the contact of rough cartilage surfaces with lubricant entrapment. Cartilage was modeled with the biphasic theory for hydrated soft tissues, to account for fluid flow into or out of the lubricant pool. The findings of this study demonstrate that under contact creep, the trapped lubricant pool gets depleted within a time period on the order of seconds as a result of lubricant flow into the articular cartilage, while for steady state sliding contact a lubricant pool cannot be sustained. These results suggest that the classical cartilage lubrication models of weeping and boosted lubrication may have to be revised. More recent mixture-based models described in the literature are able to predict the frictional response of articular cartilage without necessarily assuming or requiring entrapment of lubricant pools at the articular contact interface.