Discrete Surface Dynamics: Distributed Sprag Slip Elements in Brakes

In recent years, characteristic structures in the boundary layer of high-load contacts such as brakes have been reported, which have an important impact on the dynamics of the tribological contact. Usually, local assumptions concerning the friction of these patches are used to reach global conclusions about the brake system. Several numerical methods (e.g. Cellular Automata) have been developed which make use of such assumptions. The validation of these methods through measured data tends to be laborious and costly. Sprag-Slip elements are friction elements which are typically considered to exclusively undergo static friction. Such elements have been sporadically utilized towards describing friction in brake applications. In this paper, many locally distributed Sprag-Slip elements are used to model the global dynamics of braking friction. The results show good agreement with the measured characteristics of brakes. This approach offers new possibilities for the description of global friction dynamics, and offers significant advantages concerning measurement validation and stability analysis.