This study describes the dynamic behavior of the HEMU-430X, the Korean next-generation high-speed train. The HEMU-430X was initially analyzed using VAMPIRE, a computer program that is used to examine the dynamics of railway vehicles, based on which it was expected to sway strongly at its tail end. This hunting motion was expected to disappear when the position of the yaw damper was changed. The dynamic behavior of the HEMU-430X was assessed in an on-track test performed using the protocols in the EN14363 standard and measuring the carbody, bogie and axle accelerations; the HEMU-430X was found to satisfy the safety criterion. The hunting motion appeared at speeds of 150, 350 and 387 km/h, and countermeasures such as changing the position of the yaw damper, installing carbody dampers, and increasing the damping coefficient of the yaw damper installed on the motor car containing the driver's cab were taken in order to reduce the vibrations. Ultimately, the highest test speed achieved was 421.4 km/h. Subsequently, it was found that the critical speed tended to decrease with mileage. This was attributed to excessive lateral damping and a revised design was proposed to solve this problem.
서 론차세대Abstract This study describes the tail vibration reduction for the next generation high speed EMU(HEMU-430X). The model of 6 cars was generated and the calculation was performed using VAMPIRE(railway vehicle dynamic software). In view of ride characteristics, HEMU-430X was expected to sway at the tail because of the yaw damper direction. The lateral acceleration of vehicle body exceeded the criteria because of hunting. To reduce this hunting motion, some methods such as wheel profile change, the change of damping coefficient for the 2nd lateral damper, the damping coefficient change of yaw damper were tested, but had little effect. Finally, the yaw damper direction was changed and the tail vibration disappeared. In real running test, the tail vibration appeared at the speed of 150km/h and the yaw damper direction change made the vehicle stable at the speed of 300km/h. The maximum test speed of HEMU-430X is 430km/h. If the tail vibration appears at higher speed, some other methods in this study may be considered to reduce it.
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