The effect of the friction block installation direction on the tribological behavior and vibrational response of the high-speed train brake interface

Abstract

Abstract In this study, to investigate the effect of the hexagon friction block installation direction on the surface tribology and friction-induced vibration and noise (FIVN), tribological tests were carried out on a self-manufactured high-speed train brake dynamometer under different installation directions. Accordingly, a finite element (FE) model with material parameters and boundary conditions coinciding with the test rig was used to conduct complex eigenvalue analysis (CEA), and the Archard wear formula was employed to simultaneously study the wear and vibration. The results demonstrate that the installation direction has little effect on the frequency and mode shape of unstable modes, but the FIVN intensity, the phase-space characteristics of the friction noise, and the damping ratio of the brake system are changed. The contact stress and wear are found to be mainly distributed in the leading edge and the inner area of the friction block, leading to the severe eccentric wear phenomenon, and the friction heat is mainly concentrated in this area and the inner region of the disc friction area. The degree of uneven wear of the block is found to vary with the change of its installation direction, which also causes differences in the amount of wear debris flowing in the brake interface and the damage to the interface. Under the joint action of wear debris, friction heat, and contact stress, the brake interfaces of the brake systems with different block installation directions are found to exhibit different tribological behaviors, which affects the intensity of FIVN and the phase-space characteristics of friction noise. Therefore, it is necessary to consider the influence of the block installation direction on the tribological and dynamic behaviors of the brake interface of high-speed trains when designing the brake pad, which can aid in the development of a brake pad with excellent interface tribological behavior and friendly FIVN characteristics.