title: Dynamic system model for ultrasonic lubrication in perpendicular configuration.
abstract: Ultrasonic lubrication can be achieved by superimposing ultrasonic vibrations onto the relative sliding velocity between two surfaces. Ultrasonic vibrations are typically generated by a piezoelectric actuator. Relative to the macroscopic velocity, the vibrations can be longitudinal, transverse, or perpendicular. Often considered as a purely interfacial effect, ultrasonic lubrication is in fact a system phenomenon incorporating the dynamics of the actuator, sliding surfaces, and surrounding structure. This article presents a dynamic system model for ultrasonic lubrication configured in perpendicular mode, as experimentally measured with a modified pin-on-disc tribometer. The framework includes a lumped-parameter, dynamic model for the tribometer, an electromechanical model for the piezoelectric transducer used to generated the ultrasonic vibrations in the tribometer, and a "cube" model for the contact mechanics between asperities. Electrical impedance, system vibrations, and friction reduction are examined. Results show a strong match between experiments and simulations with errors lower than 10%. A parametric study is conducted to investigate the influence of driving voltage, macroscopic velocity, driving frequency, and signal waveform on ultrasonic friction reduction.
authors.affiliation: Smart Vehicle Concepts Center, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210, USA.
authors.forename: Sheng
authors.initials: S
authors.lastname: Dong
authors.affiliation: Smart Vehicle Concepts Center, Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH 43210, USA. Electronic address: dapino.1@osu.edu.
authors.forename: Marcelo J
authors.initials: MJ
authors.lastname: Dapino
keywords: Friction reduction; Parametric study; Piezoelectric actuator; System dynamics; Ultrasonic lubrication