Detailed analysis of drum brake squeal using complex eigenvalue analysis

Nowadays one of the major topics in the brake development community is the NVH (noise, vibration and harshness) problem. Although reasonably well researched in the disc brake systems, the squeal prediction in the drum brakes is often neglected, manly due to its complexity. The newly developed methodology presented in this work gives the directions on how to develop a squeal free drum brake design using some novel approaches to closely correlate the numerical results with the experimental brake tests. The goal is to make a robust drum brake design that is stable under the different noise factors and under broad operational conditions. In order to predict if a brake system will generate the squeal noise during the operation, the finite element method was used to simulate the system. By solving the complex eigenvalues of the FEM (finite element method) matrices, the presence of unstable modes was predicted. A good correlation with the SAE J2521 noise matrix dynamometer test procedure was established