ANALYSIS OF DIMENSIONLESS PARAMETERS OF SPEED, LOAD, AND MATERIALS IN RELATION TO THE EMPIRICAL SOLUTION OF THE EGD LUBRICATION MODEL IN THE LOCAL FRICTION CONTACT ZONE
DOI:
https://doi.org/10.18372/0370-2197.3(112).21634Keywords:
EHD lubrication model, local friction contact zone, dynamic viscosity, pressure-viscosity coefficient, lubricant film thickness, rheological properties, lubricantAbstract
This article is devoted to a comprehensive evaluation and analysis of the dimensionless parameters of velocity (U), load (W), and materials (G), which form the basis for deriving empirical solutions for the elastohydrodynamic (EHD) model of lubrication in the local friction contact zone. The problem under study is considered in the context of non-conformal friction joints (in particular, rolling bearings), where high contact pressure causes elastic deformation of the interacting surfaces and a significant change in the rheological properties of lubricants. Based on the processing of an initial dataset of experimental data for a spectrum of four transmission oils (ATF-III, SAE 75W-80, SAE 75W-90, SAE 80W-90) in the MatLab environment, multiple regression mathematical models were developed. Analytical relationships were established between the output dimensionless parameters and key input factors: dynamic viscosity, rolling speed, contact load, piezoviscosity coefficient, and reduced modulus of elasticity.
The analysis showed that the dimensionless velocity parameter U exhibits a multiplicative combined effect of dynamic viscosity and rolling speed. For the load parameter W, the contact load has a dominant direct influence, whereas dynamic viscosity has an extremely small exponent. An investigation of the material parameter G demonstrated the decisive role of the piezoviscosity coefficient of the lubricant, as opposed to the significantly less pronounced influence of the reduced modulus of elasticity of the friction pair materials. Based on the calculation results, three-dimensional (3D) surface models were constructed, which clearly demonstrate the physical characteristics of the elastic-piezo-viscous lubrication regime and confirm the adequacy and statistical significance of the mathematical relationships (according to Fisher’s F-test). The practical value of this work lies in the ability to perform high-precision analysis and prediction of the lubricant film thickness to enhance the durability of tribological interfaces.
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