Brake squeal is a well-known phenomenon in disc brakes induced by the mode coupling effect. The complex eigenvalue analysis (CEA) is widely used to identify this phenomenon by calculating the complex eigenvalues in a given frequency range. The real part of the eigenvalues is a measure for unstable oscillations corresponding with the probability of brake squeal. In various recent researches, attempts have been made to reduce the brake squeal propensity by avoiding mode coupling, e. g. by increasing the system damping or by shifting the frequencies of coupling-critical eigenmodes. The latter is a problematic task, as structural modifications often effect other non-involved eigenmodes and may cause unwanted effects. In this study, a novel heuristic approach is presented to shift the frequency of a specific eigenmode by structural modification and constraining other eigenfrequencies simultaneously. First, the complex eigenvalue analysis of a disc brake delivers the critical eigenmodes. The calculation of component contribution factors (CCF) and component mode contribution factors (CMCF) reveals the brake component and the corresponding eigenfrequency with the strongest influence onto the unstable oscillation. Secondly, the new approach is applied to the chosen brake component. The results show the potential of the new method and its limitations. Experimental investigations emphasize the effectivity of the numerical approach.
Volkswagen AG: Ing. Marcel Deutzer; TU Hamburg: Prof. Dr. Norbert Hoffmann