Multiscale friction in lubricant-surface systems for high performance transmissions under mild wear
journal contributionposted on 06.06.2018, 15:17 by Ed Humphrey, Nick Morris, Michael Leighton, Ramin Rahmani, Homer Rahnejat
The lubricant-surface system is complex in nature and can significantly affect the frictional performance of high-performance transmission systems. The complexity stems from the coupled mechanical and chemical phenomena that occur at the interfacial tooth conjunctions. A combined analytical and precision experimental approach is presented to analyse the salient parameters of the lubricant-surface system. A multiscale procedure comprising topographical measurement, pin-on-disc tribometry, atomic force microscopy in lateral force mode, X-ray photo-electron spectroscopy and continuum contact mechanics analysis under mixed non-Newtonian thermo-elastohydrodynamics is used to describe the formation of a tribo-film, as well as wear and frictional characteristics of the lubricant-surface system. The contribution of chemisorbed and physisorbed bonded tribo-film on the boundary coefficient of friction is ascertained at different physical scales. Therefore, the paper presents a novel multiscale analysis, promoting improved understanding of the complex interactions between mechanisms of friction, wear and surface chemistry.
The authors are grateful to the Engineering and Physical Science Research Council (EPSRC) for the financial support extended to this research through the Doctoral Training Program (DTP). The authors also acknowledge use of facilities within the Loughborough Materials Characterisation Centre (LMCC).
- Mechanical, Electrical and Manufacturing Engineering