Measurements of lubricant film thickness in the iso-viscous elastohydrodynamic regime

This paper describes the application of ultrasonic reflection techniques to measure the lubricant film thickness in iso-viscous elastic lubrication regime. The reflection of ultrasonic pulses from the interface between the sphere and disk was recorded for a range of lubricated, dry, static, and dynamic contact conditions. In this way profiles of oil film thickness were created for various loads and sliding speeds. It was also possible to observe cavitation effects on the signal in the exit region. The measured central film thickness results are compared with published models of the lubrication mechanism and experimental data obtained from optical methods.