Understanding the Influences of Multiscale Waviness on the Elastohydrodynamic Lubrication Performance, Part I: The Full-Film Condition

Abstract

Understanding the responses of tribosystems to multiscale roughness is fundamental for the identification of the relevant roughness scales. This work used a point-contact elastohydrodynamic lubrication (EHL) problem as a representative tribosystem and artificially generated waviness with different amplitudes, frequencies, and directions to mimic the multiscale roughness. The amplitudes and frequencies are related to the feature geometry of smooth EHL problems. This work consists of Part I (this paper), focusing on the full-film condition, and Part II, focusing on the partial-film condition. Generated waviness is input to a transient thermal EHL model. The simulation is conducted 1600 times for different waviness parameters, loads, and speeds. Seven performance parameters are extracted: the minimum film thickness, maximum pressure, central film thickness, central pressure, mean film thickness, coefficient of friction (COF), and maximum temperature rise. The ratios of these parameters with and without waviness are plotted on the frequency–amplitude coordinate plane as contour maps. The influences of the amplitude, frequency, wave direction, load, and speed on the seven performance parameters are analyzed and summarized. The simulated data and plotted contour maps are provided to the readers in the Supplementary Material.