Thermoelastic Instability of Two-Conductor Friction System Including Surface Roughness

A model is developed to investigate the mechanism of thermoelastic instability (TEI) in tribological components. The model consists of two thermally conducting bodies of finite thickness undergoing sliding contact. Appropriate governing equations are derived to predict the critical speed beyond which the TEI is likely to occur. This model takes into account the surface roughness characteristics of the contacting bodies as well as the thermal contact conductance at the interface. Analytical expressions are provided for the special cases neglecting the disk thickness and the thermal contact conductance. An extensive series of parametric simulations and discussion of the implication of the results are also presented. The simulations show that the difference in material properties and geometry of the two conducting bodies has a pronounced influence on the critical speed. A special case of the model shows that the threshold of TEI critical speed is pushed to a much higher level when the conducting bodies have identical material properties and are geometrically symmetric. It is also shown that the perturbed wave generally tends to move with the body with higher thermal conductivity.