Thermo-Mechanical Coupling Characteristics and Computation of Stress Intensity Factor of High-Speed Train Brake Disc Under Wheel–Rail Excitation

In order to research the influence of wheel–rail excitation on the stress intensity factor of the brake disc of high-speed train, finite element model of brake disc was established. The vibration characteristics of the brake disc under wheel–rail excitation and the changes of thermo-mechanical coupling temperature field and stress field were computed by combining dynamics and finite element simulation. Finally, the variation law of the stress intensity factor of the fatigue crack of the brake disc with the crack inclination angle and the distance between the two cracks under wheel–rail excitation and without wheel–rail excitation was obtained. The results show that the vibration acceleration value of the brake disc in the vertical direction is maximum. The surface temperature of the brake disc gradually decreases with the increase of the thickness. The maximum temperature under the wheel–rail excitation condition is higher than that without wheel–rail excitation condition. The stress intensity factor of mode I crack of brake disc decreases with the increase of crack angle and radial angle. The stress intensity factor of mode II increases first and then decreases with the increase of crack angle. Under the action of collinear double cracks, as the distance between the two cracks increases, the crack action parameters gradually decrease, which can effectively reduce the crack propagation in the radial direction. In the state of two parallel cracks, with the increase of the distance between the two cracks, the crack action parameters will gradually increase, while the wheel–rail excitation condition will strengthen the inhibition.