ABSTRACT
This chapter deals with steady isothermal and non-isothermal line and point EHL problems for lightly loaded smooth contacts. A lubricant is considered to be an incompressible non-Newtonian fluid of a rather general rheology. In lightly loaded lubricated contacts, the influence of the elastic properties of the solids in contact on the contact pressure is relatively small. In other words, the problem solution in the entire lubricated contact is close to the solution of the problem for a lubricant flow through a narrow gap of a known shape. The aim of the chapter is to consider lightly loaded lubricated contact by
employing the method of regular perturbations [1, 2], which allows to study the solution behavior in contacts with fluid of rather complex rheology. As a result of application of the above-mentioned method the differential equations for the first two terms of the asymptotic expansion of the problem solution for pressure, gap, and lubrication film thickness are obtained. Moreover, some new two-term analytic formulas for the lubrication film thickness and frictional forces are derived. The obtained relationships are illustrated by examples of fluids with different rheologies. In the special case of Newtonian fluid, the leading terms of the aforementioned asymptotic expansions coincide with the classic Kapitza [3] results. A thermal EHL problem for a lightly loaded contact is briefly considered. The formulas obtained for the lubrication film thickness and frictional forces
can be used in treating experimental results for lightly loaded lubricated contacts as well as for making a judgment on application of a fluid of a particular rheology.
