Thermoelastic instability in lubricated sliding between solid surfaces

Abstract

IN the past few years, it has been recognised that, in certain conditions, thermoelastic instabilities occur in dry sliding contact between two solids^1–4. We here report observations of the same phenomenon in the presence of a liquid lubricant which supports analytical predictions⁶ of such an effect. Thermoelastic instability is caused by frictional heating and thermal deformation of the surfaces in contact, and alters the original contact configuration. Even if the surfaces are perfectly flat at the outset, instability will lead to a departure from flatness, ultimately resulting in patches of high pressure in the lubricant, with surrounding regions of low pressure and relative parting of the surfaces. This instability can lead to a malfunction of, for example, mechanical face seals.