The development of silent brakes is one of the major challenges in car development. Although the extensive research conducted in the last decades led to a significantly deeper understanding of the underlying instability mechanisms, the prediction capabilities of the simulation tools are still poor. Among the variety of unsolved problems concerning the simulation of brake squeal (e.g. uncertainty of parameters and modeling of the contact interface) the role of damping and its modeling is crucial. Up to now, damping is either not modeled or inadequately modeled (e.g. Rayleigh damping), even though damping effects mainly determine the stability of the brake system. The joints in assembled structures highly contribute to the energy dissipation and introduce nonlinear behavior to the system. First investigations indicate a strong impact of joint damping on the dynamic behavior of disc brakes. However, further investigations are necessary to determine qualitatively and quantitatively the contribution of joint damping to global damping. A first step towards the integration of adequate damping models in the simulation is the identification of dominant damping effects in the brake system. To achieve this, an experimental modal analysis (using a setup consisting of caliper, brake pad and brake carrier) is conducted. Global damping of components and component assembly are identified and compared to determine mode-dependent influence of joints on global damping.
Tiedemann, M.; - Hamburg University of Technology, Kruse, S.; - Audi AG; Hoffmann, N.; - Hamburg University of Technology; Imperial College London