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Prediction and analysis of the thermo-mechanical coupling behavior in friction braking system is very important for the design and application of vehicle brakes, such as brake judder, brake squeal, brake wear, brake cracks, brake fade. This paper aims to establish a macro-structural model of the thermo-mechanical dynamics of the ventilated disc brake with asymmetrical outer and inner disc thickness, taking into account the friction-velocity curve of the disc pad couple acquired by testing. On the basis of finite elements analysis of the model, the predictions of the thermo-mechanical responses of the brake disc are presented, including disc transient temperature field and normal stress in radial, circular and axial directions, disc lateral deformation and disc thickness variation. Numerical predictions of the disc surface temperature and later distortion are compared with experimental measurements obtained by thermocouples and non-contact displacement sensors.

In order to explore the generation mechanism of hot-spots on the automotive brake disc, disc tests under non-frictional thermal loads are carried out on the brake dynamometer test bench. In the tests, the oxy-acetylene flame is used as the heat source, and the distribution characteristics of the disc temperature and displacement are measured and analyzed. To confirm the mechanism of the disc deformation, a disc thermal buckling model using finite element method is established, and the key factors for the disc thermal buckling under thermal loads are further analyzed. It is found that the temperature circumferential gradient is small but the temperature radial gradient is large. The disc presents waviness deformation mode with 5th order in circumferential direction, which is the first thermal buckling mode of the disc. A method using spatial frequency spectrum has been proposed to find the critical time and load of thermal buckling.

Brake pedal feel characteristic is determined by the structural and kinetic parameters of the components of the brake system. As the servo power component of the brake system, vacuum booster has a significant influence on the brake pedal feel. In this paper, a brake system model for brake pedal feel which has a detail vacuum booster mathematical description is established in the software MATLAB/Simulink. The structure gaps, spring preload, friction force and reaction disc characteristics of vacuum booster are considered in this model. A brake pedal feel bench test under different input velocity and vacuum pressure is completed in order to validate the prediction of the model.