Influence of contact parameters on the radiated noise from an automotive drum brake

Drum brakes are the major source of noise and vibrations in the automobile as the drum acts as a significant source of the noise. High-frequency noises are generated at the interfacial contact between the brake shoe and brake drum. Hence, the variation in the contact parameters (friction, contact stiffness, and contact damping) will significantly affect the vibro-acoustic noise emanating from the drum brake. The current work quantifies the variation in vibro-acoustic noise due to an asymmetry in the contact of leading and trailing shoes with the drum. The overall sound pressure level is estimated numerically using a finite element model of the drum brake. Multiple spring-like components in parallel between the brake shoe and the drum imitate the contact in real drum brakes. The numerical model predicts the noise generated by a symmetric system (without any asymmetry defects) and a system with controlled asymmetric defects introduced into the model. The results show that the overall sound pressure level is a strong function of the contact parameters. The current research is envisioned to better the selection of contact parameters and hence the drum and shoe properties.