Spatiotemporal analysis of thermal response characteristics in C/C-SiC brake friction pair for high-speed trains: Numerical and experimental investigation

Carbon fiber-reinforced silicon carbide (C/C-SiC) composite is a promising lightweight candidate for railway braking systems, yet the thermal response behavior of C/C-SiC brake pairs remain insufficiently understood. To address this, a thermo-mechanical coupled model of a C/C-SiC brake pair was established, and a thermal factor was proposed to elucidate and predict its thermal response characteristics. The simulated model is validated experimentally at initial braking speed (IBS) of 50-160 km/h and braking pressures of 0.50–0.75 MPa. Results indicated the simulated brake disc temperature field closely matches the experimental measurements, validating the simulated model. The influence of braking pressure on disc temperature is dependent on the friction radius, with the peak temperature localized at 115 mm, arising from the synergistic effect of the linear velocity and friction arc length. The low thermal conductivity of C/C-SiC brake materials results in a pronounced uneven temperature distribution, which is exacerbated under higher speed braking conditions. Increasing the IBS from 120 to 160 km/h at 0.50 MPa induces respective increments of 39% and 14% in the maximum radial and axial temperature differences. The proposed thermal factor successfully explains and predicts the thermal distributions. A notable finding is the 6 mm offset between the peak location of thermal factor and average temperature, resulting from the omission of convective heat exchange effects in the proposed thermal factor.