Time-varying characteristics of friction squeal and the influence of heterogeneous friction and contact characteristics based on transient simulation

Abstract

Friction squeal is a major issue for car manufacturers as it is the reason for the return of many vehicles to customer services, representing high costs for the companies. One of the reasons for the difficulty in prediction and suppression of squeal is its time-varying characteristics. Heterogeneous characteristics of friction and contact characteristics have a great effect on occurrence and evolution of friction squeal. However, the heterogeneous characteristics are always ignored. In this paper, friction squeal test is carried out, and time-varying characteristics of friction squeal are analyzed. A flexible pin-on-disc system model is established. The time-varying characteristics of friction squeal are analyzed by transient simulation, and the effectiveness of the model is verified by the bench test. Then, heterogeneous friction and contact parameters are generated and assigned to the contact surface of the model. Evaluation indexes of time domain characteristics are established to reflect the intensity of squeal. The product of friction coefficient and contact stiffness are introduced to reflect their combination effect on squeal, and the evaluation indexes of heterogeneous friction and contact characteristics are built. Furthermore, uncertainty of friction squeal time domain characteristics is analyzed, when heterogeneous friction and contact parameters are treated as random parameters. The influence of heterogeneous friction and contact parameters on friction squeal is studied by the combination of uncertainty concept and statistical analysis. The research shows that when evaluation indexes of heterogeneous friction coefficient and contact stiffness obey normal distribution, the root mean square (RMS) acceleration of the free end of the pin (RMSAFP) and squeal time (ST) obey skewed distribution. Besides, the mean value of the product of heterogeneous friction coefficient and contact stiffness is the most critical influencing factor on squeal. Squeal intensity increases with the increasing mean value of the product of heterogeneous friction coefficient and contact stiffness. Moreover, the radius of the center position of heterogeneous friction coefficient has some effect on friction squeal. The method and conclusion proposed in this article can be contributed to improving accuracy of the prediction model and providing reference for squeal suppression from the aspect of surface treatment.