Thermal Localizations in Friction Brakes

The determination of the heat gradients in friction brakes is precious data in the analysis of the friction brake performances. However, in calculations, the assumption of uniform contact pressure on the apparent friction surface is often retained. It is proposed in this paper to give a progress report on the various types of heat gradients met in the friction brakes using experimental analysis (flash temperatures, hot bands, gradients on hot bands, macroscopic hot spots, large thermal gradients due to non uniform heat exchanges, etc.), and secondly to discuss on the explanation of their origin and on the techniques of modelling. It is shown that macroscopic models may lead to satisfactory predictions on the main thermal localizations, but only if complex couplings are introduced.