Influence of Curve Geometric Parameters on Curving Performance of Sub-Frame Radial Bogie

Based on the theory of vehicle-track coupled dynamics, the dynamic model of the freight car mounted with the sub-frame bogies and the numerical model of curved track were established, utilizing the fast numerical integration method, the vehicle curving performance was simulated to study the influence of the curve geometric parameters such as curve radius, transition curve length, and superelevation of outer rail on wheel-rail dynamic interactions. The simulation results indicate that: (1) Increasing curve radius can decrease the wheel-rail wear, but the effect will weaken while the curve radius is greater than 800 m. (2) If the transition curve length is less than 30 m, vibrations will appear at the transition-circle connecting point, but when the length is bigger than 50 m, its further variation has very little effect on wheel-rail wear. (3) The superelevation of outer rail affects the distribution and difference of the inner and outer wheel-rail forces, too large deficient or excessive superelevation will worsen the wheel-rail wear either. However, an appropriate deficient superelevation of outer rail (e.g. <20 mm) is helpful to reduce the wheel-rail wear, which is consistent with the engineering practice of settling a certain deficient superelevation value.