Measures to Reduce the Lateral Vibration of the Tail Car in a High Speed Train

Abstract

From the vibration data obtained simultaneously on several cars in the same Shinkansen train, it was observed that the vibration amplitude of the tail car is greater than those of the other cars in a train. The authors' analysis arrived at the conclusion that the vibration mode of a train has a tendency for the tail car to vibrate more than the others, when the carbody hunting characteristics of a train for the yawing mode are likely to emerge, and when aerodynamic forces work in a tunnel section. Referring to those results, by simulation analysis etc., it was found that two longitudinal dampers installed parallel between the car ends (Fig. 1) with their forces depending on the angular velocity between cars, are effective in decreasing the train vibration including the tail car's vibration. Then, the prototype of the longitudinal dampers between the cars for Shinkansen was designed by obtaining the proper damping coefficient through simulation. The effectiveness of the installed damper was verified when it was tested up to 310 km/h in the Shinkansen train.

Modeling of Aerodynamic Force Acting in Tunnel for Analysis of Riding Comfort in a Train

“…The RMS values of the aerodynamic force acting on cars No.15 and No.16 are both greater between 0～10 s and 10～20 s after entering the tunnel than those after 20 s; this is regarded as a transitional effect. Here, the aerodynamic forces measured at 4 force increases as the measuring position shifts to the rear. As a result, the aerodynamic force acting on the position ⑯-1 is smallest out of the 8 measuring positions on the two cars, and the aerodynamic force acting on the position ⑯-4 is greatest.…”

“…From the above-mentioned results, it is suggested that the cars after car No. 4 or No.5 in this 8-car train model, where the aerodynamic force reaches its full magnitude and the vibrations are almost constant, should be examined for ride comfort.…”

“…In the typical Shinkansen train composed of 16 cars, cars No.1 to No.6 ～ 8 are in the "developing region", where the magnitude of the aerodynamic force increases gradually, cars No.9 to No.16, except for the rear of car No.16, are in the "steady region", where the force reaches its full magnitude, and the rear of car No.16 is in the "separation region", where the aerodynamic force increases rapidly due to the effect of wake separation (3) ．To examine the vibrations in the tunnel section and countermeasures against them, it is necessary to model the aerodynamic force generated in the tunnel. Fujimoto and Miyamoto (4) reported on the lateral vibrations of the Shinkansen train, but the effect of the aerodynamic force in tunnels was not considered.…”

Design and analysis of a magnetorheological damper for train suspension

“…Since there is no change in volume as the piston rod moves, this arrangement has the advantage that no rod-volume compensator is needed for the damper design and the fluctuation of the oil chamber volume is small during both compression and extension with this structure 9 . The total stroke of the MR damper to be used in this study will be 80 mm, which is a nominal value of the allowable displacement between the bolster and the side frame.…”

“…Therefore, semi-active suspensions are proposed to overcome those shortcomings as aforementioned in order to achieve high performance while the systems are stable and fail-safe. The main semi-active devices that have been considered for railway vehicles are variable orifice dampers [7][8][9][10] , which are composed of hydraulic cylinders and mechanical valves, so the system reliability may be reduced and the maintenance may be costly due to the use of valves. Besides, the time delays of the valves would degrade the performance of the suspension system 8 .…”