Transient EHD-friction and its relation to contact temperature

The desire to optimise profit is one of three forces (the others being human health and military advantage) powerful enough to control the direction of research. Prolonging the life of machines and increasing their efficiency by the reduction of wear and friction are two easily measurable factors contributing to profits. If friction could be controlled and optimised in all respects, the worldwide reduction in the use of resources (and the subsequent environmental benefits) would be astronomical. However, this will remain a utopian dream until we have more knowledge of the parameters controlling and affecting frictional build-up; thereby enabling us to implement friction control, with surgical precision, in all applications at all times. This work introduces a new evaluation method for detailed studies of transient friction and density. The method provides both quantitative information about lubricant properties as well as a qualitative explanation to a newly discovered thermo-physical phenomenon. It highlights the importance of a thorough thermodynamic consideration of the lubricant parameters controlling contact temperature, for more accurate elastohydrodynamic simulations.