Effect of Brake Pad Friction Block Shape on Tribological Behavior of Brake Interface of High-Speed Train

The dragging brake experiments using hexagon, pentagon and circular friction blocks were conducted on a self-developed high-speed train braking shrinkage ratio dynamometer, to investigate the influence of friction block shapes on the tribological behavior of brake interface of high-speed train. The finite element method was performed to analyze the difference of the brake interface contact behavior under different friction block shapes, and the influences of the friction block shapes on the contact pressure distribution and surface heat distribution were discussed. The results showed that the friction block shape can significantly affect the wear characteristics and contact pressure distribution of the brake interface, resulting in different temperature distribution of the disc. In this study, the surface of the hexagonal friction block was slightly worn and the size of the contact platform was relatively uniform, while the pentagonal and circular friction blocks showed visible ploughing and exfoliation, and the large contact platform accounted for a relatively high proportion. For the hexagonal friction block, a larger contact area was formed during the drag braking process between the block and the disc, which made the contact pressure more uniform and showed better contact behavior. By contrast, the contact behaviors of the cases of pentagonal friction block and the circular friction block were relatively more complex, which resulted in visible temperature concentration on the disc.