Effect of Local Contact on Temperature of Brake Disc and Friction Performance

The bilateral contact and middle contact patterns were designed for the friction blocks. The effects of local contact patterns on the surface temperature of the brake disc and friction performance were studied on the reduced-scale inertia braking test bench of track and train under the braking pressures of 0.50, 0.75 and 1.00 MPa at the braking speeds of 50, 80, 120, 160 and 200 km • h-1 respectively, and were compared with those of full contact pattern. Results show that the position of local contact has an obvious effect on the surface temperature of the disc and friction coefficient. At the speed of 200 km • h-1 and the braking pressure of 1.00 MPa, the friction coefficient is reduced by about 10% due to local contact. Compared with the full contact, the peak temperature of disc surface rises by 31%, and the maximum temperature difference is increased by 37% for the case of middle contact, while the peak temperature decreases by 11% and the maximum temperature difference decreases by 68% under bilateral contact. The reason is that the contact area coincides with the high energy area of the disc surface during the middle contact, which intensifies the temperature concentration degree, while the contact area deviates from the high energy area during the bilateral contact, which helps to improve the temperature uniformity of disc surface. © 2020, Editorial Department of China Railway Science. All right reserved.