The complex eigenvalue analysis is one of the most effective approaches to predict squeal instability and this analysis is becoming more popular due to the progress of computers recently. In order to evaluate the brake squeal instability, friction characteristics can be a key parameter because unstable frequency range and instability are dependent on the friction coefficient level. Dynamic friction surface pressure on the friction when the brake is applied is not measureable, however it can be estimated based on the pad wear condition after some mileage accumulation. As a result of pad wear investigation, the dynamic friction surface pressure was calculated and it corresponded to pad wear profile. Typical dynamic pressure distribution was assumed that the leading side pressure was higher than the trailing side for the inner pad. We applied these dynamic surface pressures to determine the spring constant in the new FEM structural model for complex eigenvalue analysis. In order to confirm the effectiveness for this analysis, we compared two different eigenvalue analyses, namely constant pressure distribution and dynamic pressure distribution based on wear investigation, as well as noise test results. According to the comparison between the two complex eigenvalue analyses and noise test results, we confirmed significant benefits by using realistic dynamic pressure distribution on the friction surface.
Koichi Nakamura, Yasushi Suganuma; - Honda R&D Co.,Ltd.