Effect of Variable Wheelset Steering Stiffness and Yaw Damper Damping on Hunting Stability

Abstract

Due to the track curvature and irregularities difference, a high-speed dedicated railway vehicle running on a high-speed railway cannot achieve a good dynamics performance when it is operated on an existing railway for conventional low-speed railway vehicle. Then an adaptive bogie which can adjust its suspension parameters, like the steering stiffness of wheelset and the damping of yaw damper, is regarded as a solution to make the high-speed train be operated on an existing railways. In this investigation, a highly nonlinear dynamics model of the adaptive bogie vehicle multi-body system is built to study the effects of wheelset steering stiffness and yaw damper damping on the vehicle dynamics. Both a straight track passing and curved tracks negotiating scenarios are considered to examine the expected range of stiffness and damping when the bogie was operated those two kinds of railways. It shows that reducing the steering stiffness of wheelset leads to a significant decrease in the critical speed of vehicle, and the critical speed of vehicle decreases significantly when the yaw damper damping is less than 500 kN⋅s/m. In case of wheel wear, the smaller the wheelset steering stiffness or the yaw damper damping is, the lower the critical speed of vehicle is. Through the analysis, the limit values of wheelset steering stiffness and yaw damper damping are proposed. When the adaptive bogie vehicle operates on the existing track, the lower limit values of wheelset steering stiffness and yaw damper damping are 12 MN/m and 200 kN⋅s/m respectively.