Thermal Elastohydrodynamic Analysis Using a Generalized Non-Newtonian Formulation With Application to Bair-Winer Constitutive Equation

Abstract

The governing equations together with a solution methodology are given which enables one to effectively handle an EHL line contact problem with simple non-Newtonian fluids including thermal effects. A computational algorithm is proposed that determines the equivalent viscosity as a function of shear strain rate for a specified constitutive equation. It is shown that the method effectively handles Bair-Winer’s rheological equation in its original form and without the need for an approximate perturbation analysis. Among the performance parameters presented are the local behavior of the shear stress as predicted by the Bair-Winer’s model and its comparison to that of the Ree-Eyrings constitutive equation. It is shown that these rheological equations predict a qualitatively similar trend for the traction coefficient. Nevertheless, depending on the operating conditions, the local shear stress as predicted by the Ree-Eyring equation may exceed the material limiting shear stress. A comparison study of the traction coefficient as predicted by the Bair-Winer’s fluid model and actual experimental measurements is also presented. The results are found to be in good quantitative agreement.

Normal and tangential oil film stiffness of modified spur gear with non-Newtonian elastohydrodynamic lubrication

“…The non-Newtonian behaviors were investigated based on an EHL model of spur gear by Larsson [5], and the transient thermal effect was investigated at a generic elastohydrodynamic line contact [6]. As for non-Newtonian lubricant, it was notable that Ree-Eyring model failed to describe large shear rate, which was pointed out by Khonsari and Hua [7]. Later, Khonsari et al analyzed the features of non-Newtonian fluid models in different boundary conditions and also discussed the validity of various rheology models over a wide range of shear rate [8].…”

History, Origins and Prediction of Elastohydrodynamic Friction

“…[46][47][48][49][50][51][52]. All produce, as might be expected, the general shape of traction curves, with varying levels of quantitative match.…”

Model and experiments to determine lubricant film formation and frictional torque in aircraft landing gear pin joints

“…Numerical simulation for a pin-joint Input parameters A set of equations (9), (13) and (19) have three unknown parameters: 1 , 2 and h c which define the relative proportions of liquid and solid contact. A MathCAD program was written to solve this set of simultaneous equations for given input conditions.…”