An investigation into evaluation methods for ride comfort of railway vehicles in the case of carbody hunting instability

Sun, Jianfeng; Chi, Maoru; Cai, Wubin; Gao, Hongxing; Liang, Shulin

doi:10.1177/0954409720949116

Cited by 17 publications

(5 citation statements)

References 18 publications

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“…This motion is characterized by a vibration frequency range of 7-9 Hz, which can be easily coupled with the first-order diamond vibration mode of the car body, thereby resulting in elastic vibration that significantly reduces passenger comfort. The second type is car body hunting, [22][23][24][25] which is occurs in case of an excessively small equivalent conicity. This motion is typically characterized by a vibration frequency range of 1-2 Hz, which can be easily coupled with the rigid body mode of the car body, thereby resulting in significant vibration and reduced passenger comfort.…”

Section: Introductionmentioning

confidence: 99%

Hunting motion of high-speed emu during cross-line operation: Mechanism and countermeasures

Yang,

Wei,

Gan

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part F:

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During the operation of the Chinese 250 km/h-level EMU, hunting occurs when the EMU crosses from Line B to Line A. Numerous tests and simulations have been conducted to investigate the mechanism of this phenomenon. Comparisons of the measured rail profiles of the two lines indicate that the left rail in Line A is higher than that in Line B at the inner rail shoulder. In addition, the top position of the right rail in Line A is approximately 2–3 mm closer to the inside than that of the right rail in Line B, with the right rail in Line A being higher than that in Line B at the inner rail shoulder. These differences cause a significant increase in the wheel–rail equivalent conicity when the EMU crosses from Line B to Line A and further cause the hunting phenomenon. Moreover, simulations and experiments are conducted to investigate the countermeasures for EMU cross-line hunting. Field test results show that both increasing the damping of the yaw damper and wheel reprofiling can improve the stability during EMU cross-line operation; however, the effect of increasing the damping of the yaw damper is limited under particularly poor wheel–rail relationship. Simulation results reveal that rail grinding of Line A referring to the Chinese 60N rail profile can also improve the stability of the EMU during cross-line operation.

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Section: Introductionmentioning

confidence: 99%

Hunting motion of high-speed emu during cross-line operation: Mechanism and countermeasures

Yang,

Wei,

Gan

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part F:

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“…To evaluate the dynamic performance of the locomotive in the case of the carbody hunting instability, the ride comfort and running stability analysis are conducted using the accelerations collected from the bogie frame and the carbody floor. According to the results obtained by Sun et al, 21 the continuous comfort method is a good choice to evaluate the ride comfort at the condition of carbody hunting instability, and the lateral comfort index C Cy is expressed as followwhere W d denotes the frequency weighted value in the lateral direction, and y¨Wd denotes the frequency weighting acceleration in the lateral direction, and T denotes the calculation window. In general, T is taken 5 s, and the lateral comfort index C Cy thus is a five-second root mean square (r.m.s.)…”

Section: Introductionmentioning

confidence: 99%

An investigation into the influence of wheel–rail contact relationships on the carbody hunting stability of an electric locomotive

Guan

Chi

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part F:

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Carbody hunting stability has attracted more and more attention due to its great influence on the dynamic performance of a railway vehicle. To fully understand the correlation between the wheel–rail contact relationship and the carbody hunting stability of an electric locomotive, the wheel–rail contact geometry analysis and the multi-body dynamics simulation are carried out in this work. The focus is on the influences of track parameters (including rail profile, rail cant and track gauge) on wheel–rail contact relationships and carbody hunting stability. A group of rail profiles are obtained by interpolating between the standard CHN60 profile and the worn rail profiles. The nominal equivalent conicity, the effective equivalent conicity and the wheel–rail contact bandwidth for a wheelset lateral displacement of ±6 mm are used to evaluate the wheel–rail contact relationship, while the lateral continuous comfort index is used to evaluate the carbody hunting stability. The simulation results show that keeping the rail cant at about 1/40 and reducing the track gauge and the wear depth at the gauge corner of rail can improve the carbody hunting stability of the electric locomotive. Furthermore, the effective equivalent conicity is a good choice to establish the relationship between the wheel–rail contact geometry and the carbody hunting stability.

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“…[16][17][18] In addition to the bogie hunting instability, the carbody hunting instability is also an important issue because it usually behaves as a low-frequency vibration which significantly deteriorates the ride comfort of human body. 19 The carbody hunting instability, manifesting as a large amplitude oscillation of carbody, usually arises at a low wheel/rail contact conicity and can be understood as a resonance phenomenon between the hunting motions of the wheelsets and the Eigen modes of the carbody from the perspective of vibration characteristics. 20,21 Matsudaira 22 observed the carbody hunting instability from an experimental study on a one-tenth scale model of a bogie car.…”

Section: Introductionmentioning

confidence: 99%

Modal parameters-based hunting stability analysis of high-speed railway vehicles considering full range of equivalent conicity

Sun

Chi

Jiao

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part K:

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The balance of vehicle parameters to avoid both the carbody and bogie hunting instabilities existing at different stage of vehicle operation is a long-standing problem. However, most of the existing researches focus on a single form of hunting instability and only take specific value of equivalent conicity as the worst case of wheel-rail contact relationship. To face this challenging problem, this paper studies the hunting stability of high-speed railway vehicles from the perspective of modal parameters based linearized analysis. The root locus analysis is carried out first to observe the modal information and hunting stability. The continuous modal tracking method is exploited to understand the variation regularity of each mode under the speed parametric excitation, especially when the frequency coupling occurs. Two objective functions related to the minimal damping ratio are proposed to indicate the severity of carbody and bogie hunting instabilities, respectively. The proposed objective functions consider the full range of running speed and wheel-rail contact conicity during operation. Starting from the objective functions, the sensitive analysis and a vector evaluated genetic algorithm are implemented to optimize the suspension parameters. Finally, the optimal solution of the suspension parameters is obtained after a generation of 20. The research method presented in this paper deepens the understanding of hunting motion and improves the vehicle stability in a simple, efficient and effective way.

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An investigation into evaluation methods for ride comfort of railway vehicles in the case of carbody hunting instability

Cited by 17 publications

References 18 publications

Hunting motion of high-speed emu during cross-line operation: Mechanism and countermeasures

Hunting motion of high-speed emu during cross-line operation: Mechanism and countermeasures

An investigation into the influence of wheel–rail contact relationships on the carbody hunting stability of an electric locomotive

Modal parameters-based hunting stability analysis of high-speed railway vehicles considering full range of equivalent conicity

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