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Investigation on brake disc deformation under asymmetric mechanical loads
ISSN: 0148-7191, e-ISSN: 2688-3627
Published October 11, 2021 by SAE International in United States
The mechanism of automobile brake hot spots is unclear, which is a problem in the brake industry. Complex coupling between friction, heat, contact, and structural is the main difficulty in revealing the mechanism of brake hot spots. This paper proposes a new way to study the mechanism of hot spots by analyzing the deformation behavior of brake discs under asymmetric mechanical load. The actual brake is simplified into a brake disc and friction lining system, and a transient dynamic finite element model under asymmetric mechanical loads is established to analyze the deformation characteristics of brake disc. It is found that the normal deformation of the brake disc under asymmetric mechanical loads consists of two parts: low-frequency bending deformation and high-frequency waviness deformation, which are caused by the squeezing effect of the asymmetric brake pressure on the brake disc and the constraint modal vibration of the brake disc. The influence of rotation speed, the magnitude and the asymmetric distribution of mechanical loads on the normal deformation of the brake disc is analyzed. It shows that the deformation has both critical speed and critical mechanical load. When the rotation speed or mechanical load exceeds critical values, the disc appears stable high-frequency waviness deformation, which propagates in the circumferential direction with high speed. However, the propagation speed is not affected by the rotation speed, the magnitude and asymmetric distribution of mechanical loads, it is very sensitive to the Young's modulus of brake disc. The research in this paper provides a reference for the analysis of the coupling behavior of brake friction, heat, contact, and structure, and it is helpful to explore the mechanism of brake hot spots.