Experimental and numerical research on the bogie hunting of a high-speed train caused by the empty stroke of yaw damper.

The yaw damper serves as a hydraulic system connecting the bogie frame with the carbody and is the most critical component to prevent unstable oscillations of high-speed vehicles. Accidently, some unexpected factors can cause the yaw damper to fail, resulting in vehicle hunting instability. In this paper, a severe bogie-hunting phenomenon was monitored during the operation of a Chinese high-speed train. Specific research on the cause and solutions was performed by experimental and numerical methods. The wheel-rail contact relationship and the dynamic performance of the yaw damper were measured and analysed to identify the primary contributor to violent bogie hunting. The results indicated that the abnormal dynamic stiffness and damping of the yaw damper caused by the compression empty stokes serve as the primary origin of this abnormal vibration. The multi-body dynamics model of the high-speed train was established by integrating the field-tested parameters. The bogie hunting phenomenon was reproduced successfully, and the influences of yaw damper parameters on bogie hunting stability were analysed to propose the optimisation scheme. Finally, two solutions were adopted to suppress the empty compression strokes of the yaw damper and verified by the roller rig test. [ABSTRACT FROM AUTHOR]