scholarly journals Influence of Bending Vibration on the Vertical Vibration Behaviour of Railway Vehicles Carbody

2021 ◽  
Vol 11 (18) ◽  
pp. 8502
Author(s):  
Mădălina Dumitriu ◽  
Ioana Izabela Dihoru
Keyword(s):  
Ride Comfort ◽  
Reference Points ◽  
Structural Vibration ◽  
Railway Vehicle ◽  
Type Model ◽  
Vertical Acceleration ◽  
Bending Vibration ◽  
Railway Vehicles ◽  
Bending Mode ◽  
Vertical Vibrations

The topic of reducing structural vibrations in the case of flexible carbodies of railway vehicles has been intensively studied, but it is still an active research topic thanks to the importance of the perspective of improving the ride comfort. However, no study has been identified in the specialty literature to feature the contribution of the vibration structural modes upon the vibration behaviour of the railway vehicle carbody. The structural vibration modes of the flexible carbodies are particularly complex; however, the first vertical bending mode holds great significance in terms of the ride comfort. This paper analyses the influence of the first vertical bending mode on the vibration behaviour in three reference points of the railway vehicle carbody in correlation with the carbody flexibility, the vehicle velocity and the suspension damping. This study relies on comparisons between the results of the numerical simulations obtained for a ‘flexible carbody’ type model of the vehicle and the ones obtained for a ‘rigid carbody’ type model. The first part of this study analyses the characteristics of the vertical vibrations behaviour of the flexible carbody based on the dynamic response of the vehicle and expressed as the acceleration power spectral density. In the second part, the influence of the vertical bending on the vertical vibrations level of the carbody is analysed using the root mean square of the vertical acceleration.

scholarly journals Effect of the Anti-Yaw Damper on Carbody Vertical Vibration and Ride Comfort of Railway Vehicle

2020 ◽  
Vol 10 (22) ◽  
pp. 8167
Author(s):  
Mădălina Dumitriu ◽  
Dragoș Ionuț Stănică
Keyword(s):  
Ride Comfort ◽  
Vertical Vibration ◽  
Theoretical Research ◽  
Railway Vehicle ◽  
Vertical Acceleration ◽  
Damping Force ◽  
Comfort Index ◽  
Lateral Vibrations ◽  
Power Spectral ◽  
Vertical Vibrations

The theoretical research on means to reduce the vertical vibrations and improve the ride comfort of the railway vehicle relies on a mechanical model obtained from the simplified representation of the vehicle, while considering the important factors and elements affecting the vibration behaviour of the carbody. One of these elements is the anti-yaw damper, mounted longitudinally, between the bogie and the vehicle carbody. The anti-yaw damper reduces the lateral vibrations and inhibits the yaw motion of the vehicle, a reason for which this element is not usually introduced in the vehicle model when studying the vertical vibrations. Nevertheless, due to the position of the clamping points of the anti-yaw damper onto the carbody and the bogie, the damping force is generated not only in the yawing direction but also in the vertical and longitudinal directions. These forces act upon the vehicle carbody, impacting its vertical vibration behaviour. The paper analyzes the effect of the anti-winding damper on the vertical vibrations of the railway vehicle carbody and the ride comfort, based on the results derived from the numerical simulations. They highlight the influence of the damping, stiffness and the damper mounting angle on the power spectral density of the carbody vertical acceleration and the ride comfort index.

Study on Improving the Ride Comfort in Railway Vehicles Using Anti-Bending Dampers

2018 ◽  
Vol 880 ◽  
pp. 207-212 ◽  
Author(s):  
Mădălina Dumitriu
Keyword(s):  
Numerical Simulations ◽  
Ride Comfort ◽  
Railway Vehicle ◽  
Vehicle Model ◽  
Bending Vibrations ◽  
Bending Vibration ◽  
Type Method ◽  
Railway Vehicles

The paper researches the possibility to reduce the bending vibrations in the railway vehicle carbody and to improve the ride comfort via a new passive type method. This would involve the fitting of the vehicle with dampers, called anti-bending dampers, fixed to the longitudinal beams of a carbody underframe. The efficiency of this method is made visible in the results derived from numerical simulations developed on the basis of a rigid-flexible coupled vehicle model. The introduction of the anti-bending dampers is seen as a significant reduction in the bending vibration of the carbody. Similarly, a relevant improvement of the ride comfort at the centre of the carbody, at high velocities. This efficiency mainly depends on the damping constant of the anti-bending damper.

scholarly journals Suppression of vertical bending and rigid-body-mode vibration in railway vehicle car body by primary and secondary suspension control: Results of simulations and running tests using Shinkansen vehicle

2009 ◽  
Vol 223 (6) ◽  
pp. 517-531 ◽  
Author(s):  
Y Sugahara ◽  
A Kazato ◽  
R Koganei ◽  
M Sampei ◽  
S Nakaura
Keyword(s):  
Rigid Body ◽  
Ride Comfort ◽  
Ride Quality ◽  
Railway Vehicle ◽  
Quality Level ◽  
Bending Vibration ◽  
Car Body ◽  
Rigid Body Mode ◽  
Bending Mode ◽  
Mode Vibration

To improve ride comfort in railway vehicles, the suppression of vertical bending vibration and rigid-body-mode vibration in the car body is essential. In this paper, a system is proposed that aims to reduce bending and rigid-body-mode vibration simultaneously by introducing damping control devices in the primary and secondary suspensions. The technique involves a control system of primary vertical dampers and air springs; the former are used to suppress the first bending mode vibration; the latter, to suppress the rigid-body-mode vibration. The results of both simulations and vehicle running tests on the Sanyo—Shinkansen line demonstrate that this system reduced vertical vibrations in the bogies and the car body using the sky-hook control theory. In the running tests in particular, the system reduced the vertical vibration acceleration PSD peak value in the first bending mode to almost 20 per cent and in the rigid body mode to almost 50 per cent compared with the case when the system was not used. As a result, the ride quality level LT (a widely used index of ride comfort in Japan) decreased by at least 3 dB, indicating greater ride comfort.

scholarly journals Influence of Suspended Equipment on the Carbody Vertical Vibration Behaviour of High-Speed Railway Vehicles

2016 ◽  
Vol 63 (1) ◽  
pp. 145-162 ◽  
Author(s):  
Mădălina Dumitriu
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Coupled Model ◽  
Large Mass ◽  
Vertical Vibration ◽  
Reference Points ◽  
Railway Vehicles ◽  
Speed Regime ◽  
Vertical Vibrations

Abstract The equipment mounted on the carbody chassis of the railway vehicles is a critical component of the vehicle in terms of ride comfort. The reason for that is their large mass, able to visibly influence the vibrations mode of the carbody. The paper examines the influence of the equipment upon the mode of vertical vibrations of the carbody in the high-speed vehicles, reached on the basis of the frequency response functions of the acceleration in three carbody reference points - at the centre and above the bogies. These functions are derived from the numerical simulations developed on a rigid-flexible coupled model, with seven degrees of freedom. As a rule, the results herein prove the influence of the equipment mounting mode (rigid or elastic), along with the speed regime, upon the level of vibrations in the carbody reference points, at the resonance frequency of the symmetrical bending mode. Similarly, it is also demonstrated how the equipment mass and the damping degree of the suspension system affect the level of the vibrations in the carbody.

scholarly journals Study on the Evaluation Methods of the Vertical Ride Comfort of Railway Vehicle—Mean Comfort Method and Sperling’s Method

2021 ◽  
Vol 11 (9) ◽  
pp. 3953
Author(s):  
Mădălina Dumitriu ◽  
Dragoș Ionuț Stănică
Keyword(s):  
Numerical Simulations ◽  
Ride Comfort ◽  
Original Model ◽  
Railway Vehicle ◽  
Type Model ◽  
Factors Affecting ◽  
Comfort Index ◽  
Vertical Vibrations ◽  
Secondary Suspension ◽  
Comfort Indices

The paper herein analyzes the ride comfort at the vertical vibrations of the railway vehicle, evaluated by two methods—mean comfort method and Sperling’s method. The two methods have in common that the estimation of the comfort sensation is conducted with the comfort indices, namely ride comfort index NMVZ and ride comfort index Wz. The values of these indices are derived from numerical simulations. The advantage of using the results of the numerical simulations versus using experimental results, on which most previous research is based, resides in the fact that the ride comfort indices can be examined while taking into account the influence of velocity and certain parameters altering the behavior of vertical vibrations of the carbody, i.e., carbody flexibility and the suspension damping. The numerical simulation applications have been developed based on a theoretical model of the vehicle that considers important factors affecting the behavior of vertical vibrations of the carbody, by means of a ‘flexible carbody’ type model and an original model of the secondary suspension. The results presented mainly show that the two assessment methods lead to significantly different outcomes, in terms of ride comfort, under identical running conditions of the vehicle.

Model Predictive Control Application to Flexible-Bodied Railway Vehicles for Vibration Suppression

2013 ◽  
Vol 10 ◽  
pp. 25-35
Author(s):  
P.E. Orukpe
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
High Speed ◽  
Ride Comfort ◽  
The Body ◽  
Ride Quality ◽  
Linear Matrix ◽  
Railway Vehicle ◽  
Railway Vehicles ◽  
Effective Manner

In this paper, we apply model predictive control (MPC) based on mixed H2/H to active vibration control of the flexibility of railway vehicle to improve ride quality. However, the flexibility in the body of high-speed railway vehicles creates difficulties which in practice may result in the body structure being heavier than what it is supposed to be. The use of active suspension helps to model the vehicle and its flexibility in an effective manner. Conventional control approaches are compared with linear matrix inequality MPC technique using flexible-bodied railway vehicle as an example. The result indicates that the MPC technique performs better in improving ride comfort compared to the passive and classical techniques when flexible modes are present.

Ride comfort of a higher speed rail vehicle using a magnetorheological suspension system

2017 ◽  
Vol 232 (1) ◽  
pp. 32-48 ◽  
Author(s):  
Sunil Kumar Sharma ◽  
Anil Kumar
Keyword(s):  
Ride Comfort ◽  
Suspension System ◽  
Magnetorheological Damper ◽  
Ride Quality ◽  
Railway Vehicle ◽  
Passive Suspension ◽  
Railway Vehicles ◽  
Rail Vehicle ◽  
Passive Suspension System ◽  
Secondary Suspension

In a railway vehicle, vibrations are generated due to the interaction between wheel and track. To evaluate the effect of vibrations on the ride quality and comfort of a passenger vehicle, the Sperling's ride index method is frequently adopted. This paper focuses on the feasibility of improving the ride quality and comfort of railway vehicles using semiactive secondary suspension based on magnetorheological fluid dampers. Equations of vertical, pitch and roll motions of car body and bogies are developed for an existing rail vehicle. Moreover, nonlinear stiffness and damping functions of passive suspension system are extracted from experimental data. In view of improvement in the ride quality and comfort of the rail vehicle, a magnetorheological damper is integrated in the secondary vertical suspension system. Parameters of the magnetorheological damper depend on current, amplitude and frequency of excitations. Three semi-active suspension strategies with magnetorheological damper are analysed at different running speeds and for periodic track irregularity. The performance indices calculated at different semi-active strategies are juxtaposed with the nonlinear passive suspension system. Simulation results establish that magnetorheological damper strategies in the secondary suspension system of railway vehicles reduce the vertical vibrations to a great extent compared to the existing passive system. Moreover, they lead to improved ride quality and passenger comfort.

Statistical Method for Investigating Transient Enhancements of Dynamical Responses due to Random Disturbances: Application to Railway Vehicle Motion

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Ewa Kardas-Cinal
Keyword(s):  
Statistical Method ◽  
Ride Comfort ◽  
Rare Event ◽  
Vehicle Body ◽  
Railway Vehicle ◽  
Dynamical Response ◽  
Vertical Acceleration ◽  
Stochastic Dynamical System ◽  
Derailment Coefficient ◽  
Vehicle Motion

Abstract The paper presents a statistical method for determining a specific variation of random excitations that leads to large transient enhancements (peaks) of a particular dynamical response in a stochastic mechanical system. Such a variation is found by calculating the weighted mean of the excitation variations close to a small number of largest peaks of the response obtained for a single long realization of the system motion. This statistical formula is derived by using the conditional expectation with respect to the rare event of unusually large response values and the ergodic theorem; optionally, a minimal interpeak distance is introduced. A similar formula gives the specific variations of other system variables around the peaks, and it can also be generalized to investigate any multivariable stochastic dynamical system or any set of correlated random signals. This method is applied to transient enhancements of quantities related to running safety and ride comfort of a railway vehicle: the derailment coefficient and the vertical acceleration of the vehicle body, respectively, obtained in simulations of the vehicle motion along a track with random irregularities. The averaged variations of the lateral irregularities and track superelevation close to the track locations of largest peaks of the derailment coefficient show characteristic oscillations leading to enhanced wheelset hunting in a short track section before the peak occurrence. A different pattern is found for the average variation of vertical track irregularities in the vicinity of the track points where largest maxima (or minima) of the vertical body acceleration occur.

scholarly journals Influences of Carbody Vertical Flexibility on Ride Comfort of Railway Vehicles

2017 ◽  
Vol 64 (2) ◽  
pp. 219-238 ◽  
Author(s):  
Mădălina Dumitriu ◽  
Cătălin Cruceanu
Keyword(s):  
Dynamic Response ◽  
Numerical Simulations ◽  
Ride Comfort ◽  
Reference Points ◽  
Railway Vehicles ◽  
Comfort Index ◽  
Traction System ◽  
Selection Of

Abstract The article investigates the influence of the carbody vertical flexibility on the ride comfort of the railway vehicles. The ride comfort is evaluated via the comfort index calculated in three reference points of the carbody. The results of the numerical simulations bring attention to the importance of the carbody symmetrical vertical bending upon the dynamic response of the vehicle, mainly at high velocities. Another conclusion is that the ride comfort can be significantly affected as a function of the symmetrical bending frequency of the carbody. Similarly, there are improvement possibilities for the ride comfort when the best selection of the stiffness in the longitudinal traction system between the carbody and bogie and the vertical suspension damping is made.

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