Elastohydrodynamic Lubrication of Elliptical Contacts for Materials of Low Elastic Modulus: II—Starved Conjunction

Abstract

By using the theory and numerical procedure developed by the authors in earlier publications, the influence of lubricant starvation upon minimum film thickness in starved elliptical elastohydrodynamic conjunctions for low-elastic-modulus materials has been investigated. Lubricant starvation was studied simply by moving the inlet boundary closer to the center of the conjunction. The results show that the location of the dimensionless inlet boundary m* between the fully flooded and starved conditions can be expressed simply as m* = 1 + 1.07 [(Rx/b)2Hmin,F]0.16, where Rx is the effective radius of curvature in the rolling direction, b is the semiminor axis of the contact ellipse, and Hmin,F is the dimensionless mimimum film thickness for the fully flooded condition. That is, for a dimension-less inlet distance m less than m*, starvation occurs; and for m ≥ m*, a fully flooded condition exists. Furthermore, it has been possible to express the minimum film thickness for a starved condition as Hmin,S = Hmin,F [(m − 1)/(m* − 1)]0.22. Contour plots of the pressure and film thickness in and around the contact are presented for both the fully flooded and starved lubrication conditions. It is evident from the contour plots that the inlet pressure contours become less circular and that the film thickness decreases substantially as the severity of starvation increases. The results presented in this report, when combined with the findings previously reported, enable the essential features of starved, elliptical, elastohydrodynamic conjunctions for materials of low elastic modulus to be ascertained.