During the braking process, abnormal noise often occurs between the friction pair of SiCp/Al composite disc and synthetic brake pad. Through 1:1 bench noise test and simulation method based on complex eigenvalue analysis, the induction mechanism, influencing factors, variation rule and noise reduction strategy of braking noise were studied. The results of MM-1000 friction reduced-scale test and simulation show that the sound pressure levels of two groups of friction pairs using SiCp/A356 composite material are lower than those of FE-928W friction pair under the same working conditions. The friction surfaces of different friction pairs show different degrees of surface scratches, material transfer and peeling, which will cause the friction pairs to have different tribological properties and contact relationships, resulting in differences in braking noise. 1:1 bench test and simulation results show that the main type of brake noise of service brake parts is brake squeal, which is induced by the braking temperature rise. Its main frequency is concentrated around 2.2?kHz, and the maximum sound pressure level can reach 110?dB(A). Braking squeal is more likely to occur when the energy input of a single brake is too large, resulting in high temperature rise of the brake parts, or when the brake temperature is kept at a high level in continuous braking for several times. The orthogonal test and the control variable method were used to study the influence law of 10 variables on the tendency of braking noise. It is found that the brake pad is the main component of the braking noise, and the friction coefficient of the friction pair and the Young's modulus have a significant effect on the tendency of braking noise. Considering the test results and simulation laws, the brake noise control strategies were proposed, such as increasing the chamfer depth of the pad friction surface, reducing the friction coefficient of the friction pair, increasing the young's modulus of the pad and controlling the brake temperature rise. In addition, compared with the original model, the instability tendency coefficient (TOI) of the new disc model established through variable selection is reduced by 81.21?%, and the brake noise tendency is obviously reduced, which verifies the effectiveness of the brake noise control strategy at the simulation level.

» Author: Zhiyong Yang, Shanshan Ye, Ziming Wang, Zhiqiang Li, Weijing Li

» Publication Date: 01/03/2023

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