A new central film thickness formula pertaining to thin film elastohydrodynamic lubrication (EHL) line contacts has been developed for Carreau-type shear-thinning lubricants using an extensive set of full EHL simulations. The shear-thinning correction factors available in the literature are based on EHL simulations carried out for a particular value of load and piezo-viscous coefficient using the simplest exponential pressure-viscosity relationship. In the present work, therefore, the load and piezo-viscous coefficient are varied over a wide range so as to arrive at a more generic and accurate film thickness equation. Also, the pressure-viscosity relation employed herein is the Doolittle's free volume-based viscosity model, which is capable of replicating the experimental pressure-viscosity data with a high degree of accuracy. It has been demonstrated that the present film thickness equation accurately captures the recently discovered scale and load sensitivity effects.

The milled fly ash (MFA) was attained by mechanical ball milling of raw fly ash (RFA) and was characterized for changes in particles morphology, size, and specific surface area (SSA). The RFA and MFA, varying in wt% from 20 to 35, were exclusively used for composite fabrication using compression molding machine.

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Thermal effect in elastohydrodynamic lubrication (EHL) has been the subject of study for the last four decades; however, some important aspects related to the physical behaviour of the lubricant in response to pressure, temperature, and shear rate remain largely neglected. This paper presents a brief review of the thermal EHL literature and sheds light on the importance of accurate characterization of the lubricant properties such as viscosity, density, rheology, and thermal conductivity. Full thermal EHL line contact simulations under steady-state and transient conditions show that using the ambient value of thermal expansivity, which has been the usual trend, may overestimate the central film thickness and introduce unrealistic features in transient EHL characteristics. Also, it is demonstrated that the most extensively used rheological equation – the sinh law – for characterizing the behaviour of shear-thinning lubricants underestimates the effect of viscous heating on EHL traction and film thickness.