This paper describes a method to identify material variations between brake discs. The method was validated with different brake discs and is used to identify batches and variation in material properties. The main goal is to see if and how two nominally identical discs differ, which may influence the noise behavior of the brake system. Since damping is sensitive to most changes and can be measured in a fast way, it is possible to monitor changes. The main aspect to achieve this goal is to control all boundary conditions so that only the material influences are measured. The result is an easy to handle, cheap and fast system, with a high sensitivity and reproducibility. This paper also shows the benefits of measuring specimen rather than complete discs.

Rausch Christian, Zerweck Janik. M-Plan GmbH, Germany. Thomas Claus, Wallner Daniel. Porsche AG, Germany.