Many engineers in academia and industry have dealt with the problem of brake squeal and performed work in this area. However, it still remains a major issue in brake development and until today there remain many open questions.

In the last decade the use of simulation methods, especially the complex eigenvalue analysis, has been extended and is used in the development process for brakes. One of the main problems of the eigenvalue analysis is that it usually overpredicts the criticality of a brake system. Depending on the brake model it finds a number of instabilities that never occur in the hardware brake system. It is a main reason for that issue that it is not possible to calculate limit cycles with the method of eigenvalue determination, because the stability of a linearized model is calculated. Hence, the method cannot determine the size of a limit cycle and hence not the noise level or its criticality.

This paper explores a harmonic balance method for the approximation of limit cycles under the assumption that joint characteristics are the main nonlinearities in a brake system. The results are used to suggest a simple method to determine critical instabilities in brake system based on the linear eigenvalue analysis widely used in industry nowadays.

Kruse, Sebastian* - Audi AG & University of Technology Hamburg Zeumer, Bernhard - Audi AG & University of Stuttgart Reuß, Pascal - University of Stuttgart Hoffmann, Norbert - University of Technology Hamburg