Research on thermal effect of braking interface of urban rail train under continuous braking condition through thermo-mechanical model

Purpose This study aims to elucidate the effects of heat accumulation on the temperature and stress distributions of the brake system, composed of a brake disc (Q345B steel) and brake pads (copper-based powder metallurgy), under continuous braking conditions. It focuses on the differences between continuous and single braking, including the formation mechanism of band-shaped high-temperature regions and their implications for thermal stress. Design/methodology/approach This study establishes a tailored thermo-mechanical model for continuous braking and uses it to analyse the radial and axial temperature and stress distributions and the formation mechanisms of high-temperature regions. The effectiveness of the model is validated through YM-I scaled test bench. Findings Under 2.32 kN braking pressure, continuous braking increases the maximum temperature by 44.5 °C (48.07%) compared to single braking. The temperature rises more rapidly in the early stage, reaching 161.7 °C in 10 s, versus 139.8 °C in 16 s for single braking, with minimal impact on cooling. Radial analysis shows the highest temperature and stress occur at 120 mm (3/4 of the brake disc radius). Stress concentration shifts from the edge to the centre, creating higher temperature and stress, causing irreversible damage to the system. Originality/value By uncovering the formation mechanism of band-shaped high-temperature regions under continuous braking. It lays the groundwork for predicting brake disc fatigue under continuous braking and offers theoretical support for establishing speed usage standards in such conditions. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2025-0010/