Experimental analysis of brake squeal noise on a laboratory brake setup

The present paper is the first of two papers dealing with brake squeal instability. An experimental setup is specifically designed for this purpose and is characterized by a simple design to aid measurements and modeling. This first paper describes the experimental setup called “laboratory brake” and presents the measurements performed on it to characterize its dynamical behavior and its squeal behavior. The tests are aimed at identifying the key parameters controlling the squeal phenomenon that are necessary to build a model of the setup. The experimental analysis on squeal presented here identifies several characteristics that lead to instabilities and correlates them with the operating parameters as well as with the dynamic behavior of the system. Measurements also highlight that the pad dynamics have a key role in the selection of the squealing modes at one of the out-of-plane eigenfrequency of the system. Finally, the experimental results provide a better understanding of the physics of the squeal mechanism and suggest guidelines to build a representative model of the setup.