Reduction of Brake Squeal Analyzed in Terms of Coupling Between In-Plane and Out-of-Plane Modes

This paper examines the onset of brake noise and the mechanisms involved during the initial stages of noise occurrence. The emphasis is directed towards disc mode coupling and improvements are suggested to inhibit the coupling of the in-plane and out-of-plane modes with similar frequencies. To better understand the mechanisms, modal analysis of the system is carried out in a static condition but with varying pressure loads. In addition the operational deflection shape (ODS) was recorded under normal braking conditions using tri axial accelerometers attached on a disc. It was identified by a 3D scanning technique during squeal braking. Through a parametric study and using complex eigenvalue analysis the disc mode shapes were reproduced and correlated to the system results. The proposals to reduce mode coupling were successfully evaluated on a brake dynamometer and the results were confirmed with vehicle testing.