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Compliant and permeable layered surfaces are used in natural synovial joints and have been proposed for the bearing surface in artificial joint replacements. The squeeze-film lubrication mechanism plays an important role in long-term performance of both natural and artificial joints. The full lubrication solution of the present problem including compliance and permeability is not available yet in the literature. The present study analyses the squeeze effect for a layered contact in two distinct cases: • Impermeable and compliant layer for a spherical contact, based on Winkler assumption. For a spherical hip joint, yields to an optimal clearance, which gives the most persistent film. • Porous and deformable layer with variable permeability, imbibed with lubricant, for spherical and plane contact, based on a novel mechanism, named Ex-Poro-Hydrodynamic (XPHD). The results obtained put in evidence an optimum initial compacticity for the porous matrix. The comparison with the well known model of McCutchen [Wear 1962;5:1-17] shows good agreement. |
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