Boundary Layer Dynamics and Sound Generation 2018-01-1900
In recent years, characteristic structures in the boundary layer of high-load contacts such as brakes have been reported, which substantially influence the dynamics of the tribological contact.
Usually, local assumptions concerning the friction behavior of these patches are used to reach global conclusions about the brake system. Several numerical methods (e.g. Cellular Automata) have been developed which employ such assumptions. The validation of these methods through measurement data tends to be laborious and costly.
Sprag-Slip elements are friction elements that are exclusively subjected to static friction, never undergoing sliding friction. Implementing such elements on a mesoscopic scale, it is possible to generate global descriptions of macroscopic stick and slip friction phenomena. Locally, these Sprag-Slip elements are similar to the patch structures in the tribological boundary layer of brakes.
The Sprag-Slip elements are suitable for describing the basic physics in the boundary layer between brake pad and rotor. Previous works have established their ability to depict principle macroscopic brake friction curves. In this paper, it is shown that characteristic boundary layer oscillations can represent characteristic braking behaviors, such as squealing and creep groan.