Stability Analysis of a Mass-Sliding Belt System and Experimental Validation as Motivated by the Brake Squeal Problem

Purpose: Brake squeal as a dynamic instability phenomenon is a major comfort problem observed in automotive disc brake systems. Thus, it is aimed to investigate the effects of certain operational parameters on squeal initiation. Methods: The problem is investigated both experimentally and mathematically from the perspective of system stability. Experimentally, a mass-sliding belt experiment is designed and built, with a focus on three key operational parameters. Experiments are conducted at a wide range of these operational parameters. Furthermore, the contact stiffness at the mass and sliding belt contact interface is evaluated via modal tests. Mathematically, a nonlinear mathematical model of the experiment is developed. The model is then linearized through certain assumptions, and the stability of the system is assessed through the linearized mathematical model via complex eigenvalue solution. Results: Data measured from the experiments are processed in time and frequency domains. Time domain results reveal local dynamic amplifications in time histories of certain operational parameters, which lead to the emergence of super-harmonics in frequency domain. Furthermore, Stribeck type friction characteristic is observed at the mass and sliding belt contact interface. The critical values of dynamic friction coefficient and motor angular speed are obtained for the validation of predictions with experimental data. Conclusion: A good correlation between the model predictions and experiments is achieved, thus the stability analysis based on linearized model is validated with the experimental data. An extensive understanding about the effects of key operational parameters on system stability is obtained.