In this article, considering the coupled interaction of heat, stress, material wear, and wheel–rail force transmission in the disc-braking process, a complex multifield coupled method was proposed to study thermal mechanical properties and contact state of brake discs. First, a coupled dynamic model of train, track, and brake gear was established to analyze the force transmission between brake friction pairs and wheel–rail system. Based on the coupled dynamics simulation results, a thermomechanical wear coupled model of the friction pair was established. It is found that the track irregularity results in vertical relative displacements with a range of (–2.6 mm, 2.8 mm) and makes the maximum brake force increase to 24.1 kN. As a comparison, brake bench tests without wheel–rail interaction were carried out. This showed that there was no vertical relative displacement between the friction pair, and the braking force had a stable value of 22.5 kN. The simulation results of the brake disc temperature distribution, and the friction pair contact state are consistent with the bench test results. In addition, different thermal simulation methods of the brake disc were used to verify the validity of the complex multifield coupled simulation results.
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