Drum Brake Squeal Analysis by Finite Element Method

Brake squeal is one of the most common problems in automobile industry that results in significant warranty cost. To reduce warranty cost due to brake squeal and provide guidance for brake design, it is important to understand the contributions of key brake design parameters for brake noise. This type of noise occurs when a brake system experiences large amplitude mechanical vibration and is audible in 1,000 to 15,000 Hz frequency range.

In this paper, an approach to study the drum brake squeal based on finite elements method (FEM) is proposed that can be used as a design tool for improving the quality of the brake system. The finite element model used in the analysis consists of several major components; drum, shoes, lining (trailing and leading)…etc. The full finite element model was used to predict the brake system natural frequency and associated mode shape. Dynamically unstable modes are found during squeal due to friction coupling of neighboring (brake drum and brake shoes) modes. The modes will be stabilized and squeal is eliminated when these modes are decoupled. Moreover, the leading and trailing brake shoes mode shapes are independent from each other with the same frequency. Good correlation with experimental results is shown where the final results identified the major parameters associated with the brake noise and also lead to an optimal design by selecting appropriate levels of those parameters. For example, the Young's modulus of the brake drum and lining materials play an important role in the occurrence of the squeal, whereas decreasing the lining coefficient of friction lead to decrease the occurrence of squeal.