This study describes the low damped carbody oscillations of the HEMU-430X, a high-speed electric-multiple-unit experimental train of Korea. The HEMU-430X had already undergone a kind of hunting problem in the test period, but it was effectively suppressed through several measures and the test was finished successfully. However, recently, the HEMU-430X again experienced the similar but slightly different problem after its wheel profile was changed to XP55, which is widely used in high-speed trains in Korea. In this paper, the eigenbehavior and system damping ratio are analyzed using a linearized vehicle model to more systematically investigate the cause of the carbody oscillation of the HEMU-430X. The results show that the bogie lateral movement coupled with carbody upper sway has the least damping ratio in the case of the HEMU-430X and the magnitude of yaw directional constraints of the bogie plays an important role in causing the carbody oscillation. Parametric studies for suspension, equivalent conicity and creep coefficients are carried out. A solution is suggested and it is validated using field tests.

这项研究描述了韩国高速电多单元实验列车HEMU-430X的低阻尼车身振动。HEMU-430X在测试期间已经经历了一种振荡问题，但通过多种措施被有效抑制，并且测试成功完成。但是，最近，在将HEMU-430X的车轮轮廓更改为XP55之后，它又再次遇到了类似但略有不同的问题，XP55在韩国的高速列车中得到了广泛使用。在本文中，使用线性化车辆模型分析了本征特性和系统阻尼比，以便更系统地研究HEMU-430X车身振动的原因。结果表明，在HEMU-430X的情况下，转向架的横向运动与车身的上摆相结合具有最小的阻尼比，并且转向架的偏航方向约束的大小在引起车身振动方面起着重要的作用。进行了悬架，等效锥度和蠕变系数的参数研究。建议了一种解决方案，并使用现场测试进行了验证。