Thermal analysis of periodic sliding contact on a braking tribometer

The thermal behaviour of a brake disc during a periodic sliding contact in braking situations is studied. The experimental tests are performed on a braking tribometer, on two types of materials used in railway applications: an organic matrix composite (OMC) for the pin and a grey cast iron for the disc. The mass temperature of the brake disc is measured 2 mm, 5 mm and 7 mm under the friction surface during a succession of stop brakings. Experimental data and an analytical model of thermal conduction determine the disc surface temperature evolution during the succession of stop brakings. Results are then compared with those estimated by pyrometry; a good correlation is found. Finally, the complex thermal transfer function of the disc, defined as the ratio of the mass and surface temperature of the disc, quantifies the temperature attenuation and the phase shift of the thermal wave in the disc.