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In this paper, the noise reduction performance of the active steering bogie, developed to address wheel and rail wear and reduce noise during train operation in curved sections, was evaluated. A prototype of the active steering bogie was installed on the test train, and noise reduction performance by active steering control was measured in curved sections of a commercial line with a radius of curve of 300 m or less. The results of the test run confirmed that both the wheel and car interior noise were reduced when active steering control was applied, compared with the case where it was not applied. According to the test results in the curved section with the most noise reduction effect, the equivalent noise level was reduced by 6.6 dB for wheels and 4.7 dB for the car body by active steering control. In addition, analyzing the frequency characteristics by wheel steering control has confirmed that the squeal noise mode generated in the 300 to 2000 Hz band during curve running was significantly reduced. Therefore, the noise reduction performance of the active steering bogie, developed to improve steering performance in curved sections, has been sufficiently verified through the test results. [ABSTRACT FROM AUTHOR]

This paper presents a study on the dynamic model and robust controller design for enhancing ride comfort in railway vehicles. An analytical model is introduced, encompassing the lateral, roll, and yaw motions of wheelsets, bogies, and the car body, while incorporating an efficient method for computing wheel-rail interactions. Rail irregularities and their impact on vibration excitation are also examined. A robust controller design methodology is proposed to address uncertainty and ride comfort quality, considering the significant variations in mass and moment of inertia experienced by railway vehicles. Through simulations, the designed controller consistently demonstrates an approximate 2 dB improvement in ride comfort across different levels of uncertainty. Future research directions include developing controller designs considering actuator response characteristics and identifying additional conditions for practical implementation. This study contributes to understanding railway vehicle dynamics and lays the foundation for effective control strategies to enhance ride comfort while accommodating uncertain operating conditions. [ABSTRACT FROM AUTHOR]

Under dynamic conditions, the dynamic force between the suspended equipment and the car body is substantially increased. This increase not only affects the ride comfort but also substantially raises the likelihood of fatigue damage to the suspended equipment. A multiobjective analytical target cascading (ATC) optimization is proposed to improve the ride comfort of high-speed trains and reduce the vibration of the suspended equipment. A mathematical simulation model of the vehicle equipment system is established, and the acceleration frequency-response function expression of the car body and the suspension system is obtained. The comfort index of the car body and the acceleration root mean square (RMS) of the suspended equipment are calculated by combining the German vertical irregular track spectrum and the comfort filter function. Meanwhile, the ATC method is used to optimize the car body comfort index and the acceleration RMS of the underframe suspended equipment. Then, the availability of the optimization method is evaluated via numerical simulation. Compared with the original suspension scheme of the underframe equipment, when the running speed of the vehicle is 300 km/h, the RMS value of the vibrational acceleration of the underframe equipment after optimization decreases by 19.9 %, and the ride comfort indexes at the car body center and above the front and rear bogies are improved by 6.4 %, 0.1 %, and 1.1 %, respectively. Simulation results demonstrate that ATC optimization can improve the railway vehicle ride comfort and reduce the vibration of the suspended equipment. This paper provides a new approach to the suspension parameter design of equipment. [ABSTRACT FROM AUTHOR]

An integrated vehicle-biodynamic model is developed in this article by using multi-domain energy domain bond graph model simulation and multi-body simulation software ADAMS VI-Rail. These models are specifically used to evaluate passenger ride comfort in a railway vehicle where vertical and lateral excitations at the wheels arise out of the track irregularities. In the bond graph model, the carbody of the railway vehicle is treated as an Euler-Bernoulli beam and its first five modes are included in the model. Thereafter, a detailed model of the railway vehicle is created in ADAMS VI-Rail. The International Organization for Standardization (ISO) 2631 specification is used to determine the passenger comfort for different travel durations and track irregularities. [ABSTRACT FROM AUTHOR]

The dynamics equations of Automatic passenger mover (APM) vehicle with the middle-guiding single-axle tire running gears were derived using linearized tire model, in which side force and rolling contact effect on running tire are taken account. A simulation model of APM vehicle based on Simulink environment was built using object-oriented programming technique, and the effects of contact statues between guiding tires and rail and different rotation modes on of curving performance and ride quality were studied. The simulation has shown that the preload force on guiding tires don't improve curving performance but significantly worsen lateral ride quality, whereas the gap between guiding tires and rail will increase the running tires side force and guiding tires radial force on curve. The gap between guide tires and rail should be controlled between 0 and 5 mm on compromising the curving performance and ride quality of APM vehicle. The cornering force of the rotating mechanism above the springs mode is greater than that of the below mode, and decreases with the increase of the curve radius, which is unfavorable to the curve passing. [ABSTRACT FROM AUTHOR]

To suppress vertical flexural vibration of a railway vehicle car body, a new passive control method by mounting dampers on the longitudinal beams of the car body underframe is proposed. The method is firstly studied by an Euler-Bernoulli beam model using Green's functions, then it is further verified by a nonlinear dynamic model of the vehicle. Results show that the car body flexural vibration can be noticeably reduced by this method. It is better to mount the damper near the car body centre. The higher damping coefficient of the damper, the more effective in decreasing the car body first vertical bending vibration. The higher the rigidity of the damper bracket and rubber bush, the better performance of the damper. It is found that when mounting six dampers at proper positions, the damping coefficient of each damper is 1.33×10 N·s/m, even if the first vertical bending frequency of the studied car body is only 7.2 Hz, a very good ride quality will be achieved when the vehicle runs at 250 km/h. [ABSTRACT FROM AUTHOR]

This study assesses the capability of an active steering bogie to run effectively on a curved track. It presents a curvature measuring method that can be implemented in a railway vehicle system to steer a railway vehicle. This method was used to conduct a field test. The angle of attack and lateral force were reduced in a railway vehicle model on a curved track and analyzed. An active steering system was implemented to improve certain states when a railway vehicle runs on this track, such as wear and derailment index. The railway vehicle was also equipped with an active steering bogie to limit lateral contact forces and wear rates between the wheel and the rail. Finally, this paper describes the modeling of this active steering system and of a system to control the performance of a vehicle as it curves. Simulation results with this bogie were better than those obtained with a conventional railway vehicle, including in terms of lateral forces and the wear number of the wheels. Therefore, the proposed model is more effective than conventional systems with respect to operation on a curved track. [ABSTRACT FROM AUTHOR]

As train operating speeds increase, upgrading the performance of the railway vehicle has been required. To improve the ride comfort related to vibration, researches to replace the conventional passive suspension with (semi)active suspension have been carried out. For the purpose of vibration reduction, the magneto-rheological (MR) damper has been widely applied in automobile or anti-vibration areas, but it hasn't yet been applied to railway vehicles. In this study, skyhook control with the MR damper was applied to the 1/5 scaled railway vehicle model on roller rig to suppress the lateral vibration of the carbody. For the 1/5 scaled prototype model of the railway vehicle, the dimensions of railway vehicle were scaled down by similarity method. Both numerical analysis and experiments to control the carbody lateral vibration were conducted and compared. The possibility of improving both the ride comfort and running stability of the railway vehicle by using the semi-active control was discussed in detail. [ABSTRACT FROM AUTHOR]

This paper deals with the lateral stability for a railway vehicle. Particularly, nonlinear critical speed is investigated via bifurcation analysis. Shooting method and trust region algorithm are applied to calculate the limit cycle of the nonlinear dynamic vehicle model. In case of the investigated vehicle model, the influences of the suspension parameters on the critical speeds are not large. The effects of friction coefficient are also small. However, there is an overall consistency that the nonlinear critical speed is decreased when the stiffness of the suspension is reduced. Study of the excitation conditions where the stable limit cycles occur gives very useful information to understand the nonlinear dynamic behavior of a railway vehicle and to test the vehicle with roller rig test stands. According to the results, the direction of the excitation is very important as well as the amplitude and frequency to acquire accurate nonlinear critical speed. [ABSTRACT FROM AUTHOR]

In this study, a standardized finite element model for the carbody structures of various railway vehicles made of sandwich composites was suggested. The standardized finite element model for composite carbody structures was introduced and proposed by comparing the results of real structural tests under vertical, compressive, twisting load and natural frequency tests of various railway vehicles. The results showed that the quadratic shell element was suitable to model the reinforced metal frame used to improve the flexural stiffness of sandwich panels compared to beam elements, and layered shells and solid elements were recommended to model the skin and honeycomb core of sandwich panels compared to sandwich shell elements. Also, the proposed standard finite element model has the merit of being applied to crashworthiness analysis just by minor modifications, such as contact conditions and constraint equations. [ABSTRACT FROM AUTHOR]

The conventional railway vehicle was designed to ensure running stability using high stiffness elements for primary suspensions. Curving performance of the railway vehicle is relatively low because the natural steering motion of a wheelset is constrained by the high stiffness suspensions. High running stability has always been in conflict with good curving performance in conventional design processes. This conflict problem can be solved with an active steering bogie since active elements properly control the wheelset motions according to track conditions such as straight or curved lines. In this paper, an active steering mechanism for railway vehicle is introduced, and the curving performance of the proposed active steering bogie is investigated through simulation and experiments. According to the results, the proposed active steering bogie is highly effective for curve negotiation. [ABSTRACT FROM AUTHOR]

Vibrations related to ride comfort should be considered at the beginning of design stage. In general, ride comfort of human is mainly affected by vibration transmitted from the floor and seat. Also, vibration level is very important regarding with running safety on freight wagon. To ensure ride comfort for passenger coach and vibration level for freight wagon, tests had been repeated by different test procedures with several equipments. With different measuring and evaluations for these results, it took much time to evaluate test results. In this paper, a new evaluation procedure was developed combining several software for ride comfort and vibration level test on railway vehicles. In addition, this developed system is capable of ride comfort test and vibration test by a single integrated system that is capable of immediate reporting the test result. With this developed system, the comfort in a passenger coach and the vibration in a freight car were evaluated. And the simulation results from the proposed system are verified by a field test. [ABSTRACT FROM AUTHOR]