Investigation of the heat distribution in dry friction systems during fade and recovery using fiber-optic sensing and infrared technology

The design of dry-running friction pairings and systems determines not only their installation space and costs, but also their reliability under critical load conditions, for example in emergencies, in the case of faults, and in the event of misuse. While knowledge of the contact pattern is highly important for the development of clutches and brakes, the contact-related measurement of the temperature of these systems has not yet been solved in a satisfactory manner. Despite its importance, the temperature distribution has only been measured in a few studies. Typically, temperature measurements of complete clutches and brakes are carried out using thermocouples only. In this study, a new innovative test setup is presented. This setup is able to measure the heat distribution of the lining and the steel disk of a brake with high spatial resolution by means of fiber optic sensing technology and thermography. As a novelty, it enables measurement of the heat distribution and allows to correlate it with the fade and recovery behavior. Contrary to the expectations, the contact pattern is heterogeneous in circumferential direction. Possible causes are discussed using simulation results. Along with surface analysis, the new setup contributes to the investigation of the causes of fade and recovery.