Paper VIII(ii) The lubrication of elliptical conjunctions in the isoviscouselastic regime with entrainment directed along either principal axis

Synopsis The study of elastohydrodynamic lubrication, in which the deformation of the contacting bodies plays an important part in the lubrication process, may be divided into two categories. Firstly, there is the regime in which the pressures generated within the conjunction cause the lubricant viscosity to increase by several orders of magnitude-the piezoviscous-elastic regime. The second regime encompasses conditions where the fluid is essentially isoviscous throughout the contact, and is therefore known as the isoviscous-elastic regime. In the 1970's the work of Hamrock and Dowson (1, 2, 3, 4) advanced the study of piezoviscouselastic point contacts considerably, although the range of solutions was restricted to conditions in which lubricant entrainment coincided with the minor axis of the contact ellipse. Subsequently, the analysis of most of the other lubrication regimes required for the construction of lubrication regime charts enjoyed comparable improvement. conjunctions which remained limited to conditions in which lubricant entrainment was aligned with the minor axis of the contact ellipse. These restriction was removed for piezoviscous-elastic contacts by Chittenden, Dowson, Dunn, and Taylor (5,6). The work presented in this report therefore seeks to remove the geometrical limitations existing in the analysis of the isoviscous-elastic regime, so as to allow lubrication regime charts to be constructed for a general case. A solution procedure is detailed, and from thirty new results computed for lubricant entrainment directed along the major axis of the contact ellipse, dimensionless minimum and central film thickness expressions are derived. With the inclusion of the existing results for entrainment coincident with the minor axis of the contact ellipse (and six new solutions for these situations) equations are developed for entrainment along either principal axis. Some of the similarities and differences between solutions in the piezoviscous-elastic and the isoviscous-elastic regime are outlined, and a comparison is made with the limited number of existing isoviscous-elastic results.

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