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.

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.

Correlation between Ride Comfort Index and Sperling's Index for Evaluation Ride Comfort in Railway Vehicles

2018 ◽  
Vol 880 ◽  
pp. 201-206 ◽  
Author(s):  
Mădălina Dumitriu ◽  
Mihai Leu
Keyword(s):  
Numerical Simulations ◽  
Critical Points ◽  
Reference Point ◽  
Ride Comfort ◽  
Dynamic Performance ◽  
Railway Vehicles ◽  
Comfort Index ◽  
Index Methods ◽  
Comfort Indices

Ride comfort is a reference point in evaluating the dynamic performance in railway vehicles. There are more methods to assess the ride comfort, depending on the traffic details and the specific needs of a railway administration. This paper focuses on the comfort index methods, in accordance with UIC Leaflet 513 R and the standard of railway applications ENV 12299, and the ride Sperling’s method, formulated by Sperling. A correlation is drawn between the comfort indices corresponding to the two methods, based on the link between the comfort and the values of these indices. The comfort indices derived from the two methods by numerical simulations help with validating the fact that, in general, the velocity influences the vertical ride comfort, and, in particular, the position of the carbody critical points, from the perspective of the ride comfort.

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.

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.

Performance Evaluation of Train Suspension Energy Harvesting Shock Absorber on Railway Vehicle Dynamics

2018 ◽  
Author(s):  
Yu Pan ◽  
Sijing Guo ◽  
Ruijin Jiang ◽  
Yong Xu ◽  
Zhiwen Tu ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Vehicle Dynamics ◽  
Shock Absorber ◽  
Ride Comfort ◽  
Average Power ◽  
Modern Society ◽  
Railway Vehicle ◽  
Railway Transportation ◽  
Suspension Dynamics ◽  
Secondary Suspension

Railway transportation has been increasingly significant for modern society in recent decades. To enable smart technology, such as health monitoring and electromagnetic braking for railway vehicles, a mechanical motion rectifier (MMR) based energy harvesting shock absorber (EHSA) has been proposed and proved to be capable of scavenging energy from the train suspension vibration. When installed on the train, MMR-EHSA works as a tunable damper in parallel with an inerter. This new suspension form brings great potential for further optimization of suspension dynamics but is rarely researched before. In this paper, the influence of the energy harvesting shock absorber (EHSA) on the railway vehicle dynamics performance is studied. A ten-degree of freedom vehicle model is established, with MMR shock absorber’s nonlinearity taken into account, with the purpose to analyze the influence of the EHSA on the ride comfort and wheel-rail vertical forces. Simulations are conducted by replacing the traditional shock absorber from train secondary suspension with the EHSA. Results show that EHSA could respectively harvest 180 W and 40 W average power at AAR 6th and 5th rail irregularity. In addition, compared with the traditional shock absorber, the MMR-EHSA can provide a higher ride comfort for passengers and slightly reduce the wheel-rail contact force.

Ride Quality of High-Speed Trains Traveling Over the Corrugated Rails

2006 ◽  
Author(s):  
H. Farahpour ◽  
D. Younesian ◽  
E. Esmailzadeh
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
The Body ◽  
Ride Quality ◽  
Comfort Index ◽  
Suspension Systems ◽  
Power Spectral ◽  
High Speed Trains ◽  
Train Speed ◽  
Secondary Suspension

Ride comfort of high-speed trains is studied using Sperling's comfort index. Dynamic model is developed in the frequency domain and the power spectral density (PSD) of the body acceleration is obtained for four classes of tracks. The obtained acceleration PSD is then filtered using Sperling's filter. The effects of the rail roughness and train speed on the comfort indicators are investigated. A parametric study is also carried out to evaluate the effects of the primary and secondary suspension systems on the comfort indicators.

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.

Evaluation of Ride Comfort in a Railway Passenger Vehicle With Integrated Vehicle and Human Body Bond Graph Model

2017 ◽  
Author(s):  
Smitirupa Pradhan ◽  
Arun Kumar Samantaray ◽  
Ranjan Bhattarcharyya
Keyword(s):  
Ride Comfort ◽  
Graph Model ◽  
Bond Graph ◽  
Railway Vehicle ◽  
Domain Modeling ◽  
Passenger Vehicle ◽  
Air Spring ◽  
Energy Domain ◽  
Railway Passenger ◽  
Secondary Suspension

Ride comfort is the level of comfort sensed by the passengers when they are continuously exposed to the vibration and noise. To diminish the vibration level, air springs are used in the secondary suspension system instead of coil springs, especially in the modern railway vehicles. This article focuses on the modeling of Nishimura air spring with non-linear damper and human biodynamic (bio-mechanical) model by using multi-energy domain modeling approach, bond graph. The car body of the railway vehicle is treated as a beam and the first five modes including three flexible modes are considered in the model. We use International Organization for Standardization 2631 for evaluating ride comfort for different durations of the travel time (1 h, 2.5 h, 4 h and 8 h) on flexible and irregular tracks.

scholarly journals Evaluation of Ride Comfort in a Railway Passenger Car Depending on a Change of Suspension Parameters

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8138
Author(s):  
Ján Dižo ◽  
Miroslav Blatnický ◽  
Juraj Gerlici ◽  
Bohuš Leitner ◽  
Rafał Melnik ◽  
...  
Keyword(s):  
Standard Method ◽  
Ride Comfort ◽  
Theoretical Background ◽  
Suspension System ◽  
The Body ◽  
Passenger Car ◽  
Comfort Index ◽  
Suspension Parameters ◽  
Railway Passenger ◽  
Secondary Suspension

Ride comfort for passengers remains a pressing topic. The level of comfort in a vehicle can influences passengers’ preferences for a particular means of transport. The article aims to evaluate the influence of changes in suspension parameters on the ride comfort for passengers. The theoretical background includes a description of the applied method for a creating the virtual model of an investigated vehicle as well as the method of evaluating the ride comfort. The ride comfort of the vehicle is assessed based on the standard method, which involves calculating the mean comfort method, i.e., ride comfort index NMV in chosen points on a body floor. The NMV ride comfort index (Mean Comfort Standard Method) requires the input of acceleration signals in three directions. The rest of the article offers the results of simulation computations. The stiffness–damping parameters of the primary and secondary suspension systems were changed at three levels and the vehicle was run on the real track section. The ride index NMV was calculated for all three modifications of the suspension system in the chosen fifteen points of the body floor. It was found that lower values in the stiffness of the secondary suspension system lead to lower levels of ride comfort in the investigated railway passenger car; however, lower values in the stiffness–damping parameters of the primary suspension system did not decrease the levels of ride comfort as significantly.

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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