Elastohydrodynamic lubrication of a circular point contact for a compliant layered surface bonded to a rigid substrate Part 2: Numerical results

Both the theoretical formulation and the numerical analysis of the elastohydrodynamic lubrication problem of a circular point contact of a compliant layered surface firmly bonded to a rigid substrate have been present in the earlier paper, Part 1. The numerical method is applied, in this paper, to a compliant layered surface firmly bonded to a rigid substrate. The results of the film thickness and pressure distribution are presented for a wide range of ratios of the contact radius to the layer thickness and Poisson's ratio. It has been shown that the film thickness for a layered surface can be predicted from the semi-infinite solid assumption when the ratio of the contact radius to the layer thickness is less than or equal to 0.25. Furthermore, it has been demonstrated that, for a layered surface with Poisson's ratio equal to 0.4, the elastohydrodynamic solutions based on the simple constrained column model are reasonably accurate when the contact radius is larger than or equal to the layer thickness. General non-dimensional solutions of the minimum and central film thicknesses have been presented using the Moes load and film thickness parameters as a function of the ratio of the contact radius to the layer thickness and Poisson's ratio. All the numerical solutions of both the central and the minimum (along the centre of contact in the entraining direction) film thicknesses have been curve fitted using a least-squares technique. A normal human hip joint has been chosen as an example to illustrate the application of the present study.