Research on the friction performance and structural optimization of brake pads considering train brake disc temperature

Brake disc temperature is a key factor in the design of brake pads for railway vehicles. However, little attention has been given to the effect of the brake pad structure on initiation time and area ratio of high-temperature zone on the disc. In this work, braking experiments are carried out under the initial braking speeds (IBSs) of 50, 120 and 160 km/h to investigate the effect mechanism between the brake pad surface morphology and brake disc temperature. In addition, three finite element models composed of circular, perforated and grooved pads and discs are established to clarify the relationship between the brake pad structure and brake disc temperature. Experimental results indicate that when the IBS increases from 50 to 160 km/h, the brake disc peak temperature rises from 120 degrees C to 292 degrees C, and the average coefficient of friction (COF) decreases from 0.411 to 0.354, which can be attributed to the thermal softening of copper matrix and formation of the third body layer. The simulated model is validated against experimental results. Simulated results indicate that compared with circular brake pad, the initiation times of high-temperature zones of perforated and grooved pads are delayed by 4 s and 2 s, and the area ratios are reduced by 2 % and 8 %.