Abstract
Low-frequency carbody swaying on China’s high-speed trains is not only an impediment to ride comfort but it may also be an operational risk under some extreme situations. To study the mechanism and mitigate the carbody swaying problem for high-speed trains, a multibody dynamics model was established based on both linear and nonlinear analyses. Whilst it is generally assumed that carbody swaying is predominantly caused by carbody hunting motion, the results in this paper has shown that, under certain boundary conditions, bogie-hunting motion can also lead to low-frequency carbody swaying. This low-frequency swaying phenomenon was also found to be caused by the excessively low wheel-rail contact or mismatched suspension parameters. Parametric optimization analysis was accordingly conducted from the perspective of the wheel-rail contact relationship and the suspension system. The analysis indicated that although optimizing the suspension parameters can meet the requirement of vehicle stability, bogie's vibration worsen when the wheel profiles wear over time. Overall, while rail reprofiling was found to be one of the fundamental solutions to mitigate carbody swaying, it is cost prohibitive for most routine operational applications. Thus, for economic considerations and the fact that low wheel-rail contact conicity is also a contributing factor to carbody swaying, vehicles with worn wheels can also be operated on the rail line, which was successfully verified by the field data presented in this paper.
Highlights
With the rapid development and widespread application of China’s high-speed railway systems, the phenomenon of low-frequency carbody swaying, which is a function of vehicle hunting motion, has become an increasing occurrence during high-speed vehicle operations. e hunting motion of the vehicle system is essentially an issue of vehicle system stability that can be divided into carbody and bogie-hunting motions [1]
Based on the field test and simulation analysis of the carbody swaying phenomenon under low contact conicity presented in this paper, the following conclusions can be drawn: (1) e field test showed that, unlike traditional cognition, the carbody swaying phenomenon can occur at high speeds. is can significantly affect the ride index and the passenger’s comfort with the carbody swaying behavior
(2) Unlike the traditional carbody hunting stability, carbody swaying at high speed is a function of the bogie-hunting motion caused by the low equivalent conicity and the unreasonable matching of the suspension parameters under the wheel-rail matching relationship
Summary
With the rapid development and widespread application of China’s high-speed railway systems, the phenomenon of low-frequency carbody swaying, which is a function of vehicle hunting motion, has become an increasing occurrence during high-speed vehicle operations. e hunting motion of the vehicle system is essentially an issue of vehicle system stability that can be divided into carbody and bogie-hunting motions [1]. Improving the wheel-rail contact relationship and adjusting the suspension system parameters are considered as some of the key remedial measures to eliminate or reduce carbody swaying. The reason for carbody swaying is considered to be related to the vibration transmitted from the bogie-hunting motion due to low wheel-rail contact conicity and mismatching of the suspension parameters. E study results showed that the adjustment of the suspension parameters can improve the vehicle-swaying phenomenon with the new wheel profiles, the bogie’s vibration would still be affected by the worn wheel profiles. Considering economic conditions and other factors, the train can operate on the concerned line with worn wheel profiles Field data supported this and substantiated that this method can effectively reduce the carbody swaying phenomenon. The limiting values for ride comfort are 2.5, 2.75, and 3.0 for excellent, medium, and qualified levels, respectively
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