Thermo - mechanical instabilities in friction contact

TL;DR

This paper investigates thermo-mechanical instabilities causing cylinder corrugation in automotive engines, highlighting the role of heat, friction, and critical velocity in the onset of such tribological issues.

Contribution

It introduces an analytical framework to predict thermo-mechanical instabilities in piston-cylinder systems, emphasizing the impact of heat and friction coefficients.

Findings

Heat significantly influences cylinder corrugation onset.

Critical velocity is key to instability occurrence.

Friction coefficient affects the stability threshold.

Abstract

The phenomenon of corrugated surfaces is a known technical problem of tribological systems; considerable work has been published in the past on the aspect of rail corrugation of railway systems. Less known is a similar phenomenon observed within the cylinder-piston system of advanced automotive engines using aluminium cylinders. This paper investigates the condition leading to cylinder corrugation in the piston/cylinder system. Material investigations strongly indicate that heat in the contact is playing a major role. Using basic analytical relationships from contact mechanics, the condition required for the onset of such thermo-mechanical instabilities are investigated. Using the concept of a critical velocity it is shown that such instabilities can occur for a realistic set of parameters. A significant technical key factor is the friction coefficient.