The performance failure of yaw damper caused by air entering its inner tube and its impact on hunting instability of an intercity train

Abstract

Listen

Translate article

The yaw damper, employed to mitigate the relative yaw motions between the carbody and the bogie frame, is critical in ensuring the vehicle’s hunting stability. During a roller rig test, bogie hunting instability was observed in an intercity train, attributed to the performance failure of the yaw damper. To investigate this failure further, a physical parameter model, validated through static and dynamic test data, was established to capture the yaw damper performance under normal and faulty states. Then, the vehicle hunting stability was analyzed using the vehicle dynamic model, considering different numbers of faulty yaw dampers. The results indicate that the entry of free air into the inner tube, followed by its passage through the damper valve, induces the damping characteristics failure of the yaw damper. As the number of faulty yaw dampers increases, subcritical bifurcation and grazing bifurcation are observed at lower speeds, causing serious bogie hunting instability and further deteriorating the operational safety and ride comfort of the vehicle. The research offers theoretical support for structure improvement and performance optimization of the yaw damper to avoid the above failure.