scholarly journals Research on Low-Frequency Swaying Mechanism of Metro Vehicles Based on Wheel-Rail Relationship

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yixuan Shi ◽  
Huanyun Dai ◽  
Qunsheng Wang ◽  
Lai Wei ◽  
Huailong Shi
Keyword(s):  
Ride Comfort ◽  
Low Frequency ◽  
Railway Vehicle ◽  
Initial Contact ◽  
Lateral Direction ◽  
Vehicle System ◽  
Locus Method ◽  
Multibody Dynamic ◽  
Hunting Frequency ◽  
Equivalent Conicity

For the worn state of the wheel, metro vehicles often suffer a serious carbody swaying issue, which causes the lateral stability of the vehicle to exceed the limit and affects the ride comfort. An experimental test was carried out on this investigation to study the carbody swaying of the metro vehicle. The field results show that the vehicle system vibrates at around 2.5 Hz in the lateral direction, which leads to the low-frequency swaying on the carbody. In order to explore the formation mechanism of the carbody low-frequency swaying and its relationship with the geometry matching of wheel-rail contact, measured rail and wheel profiles are employed to present a comparative analysis with respect to the initial contact geometry. A multibody dynamic railway vehicle system is established further. Time-domain simulations state that the 2.5 Hz vibration on the carbody belongs to the natural frequency of the vehicle, and the amplitude is larger for the measured wheels than that of the standard wheel profiles. By using the root-locus method, it can be determined that the 2.5 Hz vibration corresponds to the upper swaying mode of the carbody. With the increase in the wheel-rail equivalent conicity, the hunting frequency of bogie increases gradually, which converts frequency with the upper swaying frequency of carbody and leads to carbody low-frequency swaying.

Effect of Low-Frequency Vibration on Human Body in Standing Position Exposed to Railway Vehicle

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Rajesh Govindan ◽  
Suraj Prakash Harsha
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Human Body ◽  
Low Frequency ◽  
Vertical Direction ◽  
Standing Position ◽  
Mode Shapes ◽  
Railway Vehicle ◽  
Lateral Direction ◽  
Low Frequency Vibration

In this paper, the dynamic characteristics of the human body were investigated by developing a 3-D finite element model based on 50th percentile anthropometric data for a 54 kg Indian male subject in standing position by considering human body segments as an ellipsoid. The finite element modal analysis is carried out to extract several low-frequency vibration modes and its vibration mode shapes were presented in this paper. The results show that the lowest natural frequency of the standing passenger model occurs in the fore-and-aft direction. The second natural frequency occurs in the lateral direction and the first order natural frequency of the standing passenger model in the vertical direction occurs at 5.379 Hz. The model will be helpful to predict the vibration response of human body under various vibration environment encounters in the railway vehicle.

Vibration control and electromagnetic interference analysis of high-speed railway vehicle system with magneto-rheological damper

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1439-1445
Author(s):  
Xinna Ma ◽  
Shaopu Yang ◽  
Wenrui Shi
Keyword(s):  
Electromagnetic Interference ◽  
High Speed ◽  
Ride Comfort ◽  
Adaptive Fuzzy Control ◽  
Mr Damper ◽  
Railway Vehicle ◽  
High Speed Railway ◽  
Mr Dampers ◽  
Vehicle System ◽  
Magneto Rheological

With running speed increases, the dynamics characteristic of railway vehicle system behaves intensively, such as, snaking motion, bifurcation problem, even digression accident. These questions effect ride comfort and run stationary. The magneto-rheological (MR) damper can continually change its state in a few milliseconds and has low energy requirement and insensitivity to the temperature and circumstance. MR dampers have turned out to be a promising device in vibration control. According to the nonlinear of MR damper and the vibration characteristic of semi-active suspension of high-speed vehicle, a seventeen-degree-of-freedom lateral semi-control model of high-speed whole vehicle with MR dampers is established. Taking into account of the vibrations of vehicle and electromagnetic interference, a novel adaptive fuzzy control strategy is put forward. The simulation results show that adaptive fuzzy control method can improve the ride comfort and restrain electromagnetic interference. The electromagnetic interference noise problems in high-speed railway vehicle system with MRD are analyzed and discussed according to EN 55022 for the first time.

scholarly journals Numerical Investigation into the Critical Speed and Frequency of the Hunting Motion in Railway Vehicle System

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Jianfeng Sun ◽  
Maoru Chi ◽  
Wubin Cai ◽  
Xuesong Jin
Keyword(s):  
High Speed ◽  
Critical Speed ◽  
Dynamic Performance ◽  
Decisive Role ◽  
Creep Model ◽  
Railway Vehicle ◽  
Sudden Increase ◽  
Nonlinear Creep ◽  
Vehicle System ◽  
Hunting Frequency

The critical speed and hunting frequency are two basic research objects of vehicle system dynamics and have a significant influence on the dynamic performance. A lateral dynamic model with 17 degrees of freedom was established in this study to investigate the critical speed and hunting frequency of a high-speed railway vehicle. The nonlinearities of wheel/rail contact geometry, creep forces, and yaw damper were all considered. A heuristic nonlinear creep model was employed to estimate the contact force between the wheel and the rail. The Maxwell model, which covers the influence of the stiffness characteristic, is used to simulate the yaw damper. To reflect the blow-off of the yaw damper, the damping coefficient is described by stages. Based on the mathematical model, the combined effects of vehicle parameters on the critical speed in the straight line and hunting frequency of the wheelset were investigated innovatively. The novel phenomenon that the hunting frequency exhibits a sudden increase from a smaller value to a larger value when the blow-off of the yaw damper occurs was discovered during the calculations. The extents to which various parameters affect the critical speed and hunting frequency are clear on the basis of the numerical results. Moreover, all of the parameter values were divided into three sections to determine the sensitive range for the critical speed and hunting frequency. The results show that the first section of values plays the decisive role on both the critical speed and the hunting frequency for all parameters analyzed. The investigation in this paper enriches the study of hunting stability and gives some ideas to probably solve the abnormal vibrations during the actual operation.

Multirate Integration for Multibody Dynamic Analysis With Decomposed Subsystems

1999 ◽  
Author(s):  
Sung-Soo Kim ◽  
Jeffrey S. Freeman
Keyword(s):  
Dynamic Analysis ◽  
Multibody System ◽  
Equations Of Motion ◽  
Low Frequency ◽  
Inertia Force ◽  
Integration Scheme ◽  
Integration Algorithm ◽  
Multibody Dynamic ◽  
Higher Order Derivative ◽  
Derivative Information

Abstract This paper details a constant stepsize, multirate integration scheme which has been proposed for multibody dynamic analysis. An Adams-Bashforth Moulton integration algorithm has been implemented, using the Nordsieck form to store internal integrator information, for multirate integration. A multibody system has been decomposed into several subsystems, treating inertia coupling effects of subsystem equations of motion as the inertia forces. To each subsystem, different rate Nordsieck form of Adams integrator has been applied to solve subsystem equations of motion. Higher order derivative information from the integrator provides approximation of inertia force computation in the decomposed subsystem equations of motion. To show the effectiveness of the scheme, simulations of a vehicle multibody system that consists of high frequency suspension motion and low frequency chassis motion have been carried out with different tire excitation forces. Efficiency of the proposed scheme has been also investigated.

scholarly journals Research on Bogie Frame Lateral Instability of High-Speed Railway Vehicle

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Chen Wang ◽  
Shihui Luo ◽  
Ziqiang Xu ◽  
Chang Gao ◽  
Weihua Ma
Keyword(s):  
High Speed ◽  
Dynamics Simulation ◽  
Lateral Acceleration ◽  
Railway Vehicle ◽  
Lateral Instability ◽  
Bogie Frame ◽  
High Speed Railway ◽  
Long Time ◽  
Line Test ◽  
Equivalent Conicity

In order to find out the reason for the bogie frame instability alarm in the high-speed railway vehicle, the influence of wheel tread profile of the unstable vehicle was investigated. By means of wheel-rail contact analysis and dynamics simulation, the effect of tread wear on the bogie frame lateral stability was studied. The result indicates that the concave wear of tread is gradually aggravated with the increase of operation mileage; meanwhile the wheel-rail equivalent conicity also increases. For the rail which has not been grinded for a long time, the wear of gauge corner and wide-worn zone is relatively severe; the matching equivalent conicity is 0.31-0.4 between the worn rail and the concave-worn-tread wheel set. The equivalent conicity between the grinded rail and the concave-worn tread is below 0.25; the equivalent conicities are always below 0.1 between the reprofiled wheel set and various rails. The result of the line test indicates that the lateral acceleration of bogie frame corresponding to the worn wheel-rail can reach 8.5m/s2, and the acceleration after the grinding is reduced below 4.5m/s2. By dynamics simulation, it turns out that the unreasonable wheel-rail matching relationship is the major cause of the bogie frame lateral alarm. With the tread-concave wear being aggravated, the equivalent conicity of wheel-rail matching constantly increases, which leads to the bogie frame lateral instability and then the frame instability alarm.

Kinematic Analysis and Simulation on Parallel Vibration Reduction Seat

2011 ◽  
Vol 464 ◽  
pp. 195-198
Author(s):  
Qi Zhi Yang ◽  
Guo Quan Huang ◽  
Chen Long ◽  
Xiao Bing Zhu
Keyword(s):  
Ride Comfort ◽  
Vibration Reduction ◽  
Simulation Models ◽  
Vibration System ◽  
Good Effort ◽  
Seat Suspension ◽  
Vehicle System ◽  
Adams Software ◽  
Seat Vibration ◽  
Vehicle Seat

Vibration of vehicle system is a typical vibration of multi-degree freedom. The damping performance of multi-degree freedom seat suspension is important to ride comfort of vehicle occupants. Based on the multi-dimensional movement principle of parallel mechanism, it is built a new vehicle seat with 3-DOF suspension. It is Established a kinematics model and then analyzed the theory of the displacement of the parallel vehicle seat system. Finally, using ADAMS software to build the simulation models of seat suspension, it is showed that the seat vibration system has a good effort on vibration reduction.

Development of a reduced dynamic model for comfort evaluation of rail vehicle systems

2016 ◽  
Vol 230 (4) ◽  
pp. 489-504 ◽  
Author(s):  
Mortadha Graa ◽  
Mohamed Nejlaoui ◽  
Ajmi Houidi ◽  
Zouhaier Affi ◽  
Lotfi Romdhane
Keyword(s):  
Dynamic Model ◽  
Degrees Of Freedom ◽  
Dynamic Models ◽  
Railway Vehicle ◽  
Passenger Comfort ◽  
Rail Vehicle ◽  
Vehicle System ◽  
Comfort Evaluation ◽  
Complex Models ◽  
Reduced Dynamic

In this paper, an analytical reduced dynamic model of a rail vehicle system is developed. This model considers only 38 degrees of freedom of the rail vehicle system. This reduced model can predict the dynamic behaviour of the rail vehicle while being simpler than existing dynamic models. The developed model is validated using experimental results found in the bibliography and its results are compared with existing more complex models from the literature. The developed model is used for the passenger comfort evaluation, which is based on the value of the weighted root mean square acceleration according to the ISO 2631 standard. Several parameters of the system, i.e., passenger position, loading of the railway vehicle and its speed, and their effect on the passenger comfort are investigated. It was shown that the level of comfort is mostly affected by the speed of the railway vehicle and the position of the seat. The load, however, did not have a significant effect on the level of comfort of the passenger.

scholarly journals Dynamic performance analysis and parameters perturbation study of inerter–spring–damper suspension for heavy vehicle

2020 ◽  
pp. 146134842096289
Author(s):  
Xiaofeng Yang ◽  
Long Yan ◽  
Yujie Shen ◽  
Hongchang Li ◽  
Yanling Liu
Keyword(s):  
Ride Comfort ◽  
Dynamic Performance ◽  
Low Frequency ◽  
Angular Acceleration ◽  
Vertical Vibration ◽  
Heavy Vehicle ◽  
The Road ◽  
Multi Objective Genetic Algorithm ◽  
Parameters Perturbation ◽  
Dynamic Performance Analysis

Inerter, a new type of mass element, can increase the inertia of motion between two endpoints. In order to study the dynamic inertia effect of inerter–spring–damper suspension for heavy vehicle on ride comfort and road friendliness, the inerter–spring–damper suspension is applied and its mechanism is studied. This paper establishes a half vehicle model of inerter–spring–damper suspension for heavy vehicle. The parameters of inerter–spring–damper suspension for heavy vehicle are optimized by multi-objective genetic algorithm and system simulations are carried out. The parametric influence of different spring stiffness, damping coefficient, inertance, and load on suspension performance is also studied. The simulation results demonstrate that the centroid acceleration and pitch angular acceleration are improved by 24.90% and 23.54%, respectively, and the comprehensive road damage coefficient is reduced by 4.05%. The results illustrate that the inerter–spring–damper suspension can decrease the vertical vibration of vehicle suspension especially in low frequency and reduce the road damage. The analyses of suspension parameters perturbation reveal their different effect laws of the different wheels on vehicle ride comfort and road friendliness, which provide a theoretical basis for setting parameters of inerter–spring–damper suspension.

Spectral Distribution of Derailment Coefficient in Non-Linear Model of Railway Vehicle–Track System With Random Track Irregularities

2013 ◽  
Vol 8 (3) ◽  
Author(s):  
Ewa Kardas-Cinal
Keyword(s):  
Spatial Frequency ◽  
Second Harmonic ◽  
Lateral Displacement ◽  
Strong Dependence ◽  
Contact Forces ◽  
Railway Vehicle ◽  
Characteristic Structure ◽  
Window Width ◽  
Derailment Coefficient ◽  
Hunting Frequency

Improving the running safety and reducing the risk of derailments are the key objectives in the assessment of the running characteristics of railway vehicles. The present study of the safety against derailment is focused on the effect of wheelset hunting on the derailment coefficient Y/Q and, especially, how it is reflected in the power spectral density (PSD) of Y/Q. The lateral Y and vertical Q forces at the wheel/rail contact are obtained in numerical simulations for a four-axle railway vehicle moving at a constant velocity along a tangent track with random geometrical irregularities. The PSD of Y/Q, calculated as a function of spatial frequency, is found to have a characteristic structure with three peaks for the leading wheelsets and one peak for the trailing wheelsets of the front and rear bogies. The positions of the PSD maxima remain unchanged with increasing ride velocity, while their magnitudes and shapes evolve. One of the PSD peaks occurs for all wheelsets at the same spatial frequency corresponding to the wheelset hunting, while an additional peak at the double hunting frequency is found for the leading wheelsets. Such a peak structure is also found in the PSD of Y/Q determined in simulations with modified parameters of the vehicle primary suspension and for different track sections. The peak at the double hunting frequency is shown, by a detailed analysis of the contact forces, the flange angles and their PSDs, to result from the nonlinear geometry of the wheel/rail contact leading to the second-harmonic term in Y/Q. The emergence of this peak is also closely related to the phase difference between the hunting oscillations of the wheelset lateral displacement and the oscillations of its yaw angle, for which the difference is significantly smaller for the leading wheelset than for the trailing one. Finally, the effect of wheelset hunting is also shown to manifest itself in the strong dependence of the running average of Y/Q, which is used in the railway technical safety standards for the assessment of the safety against derailment (with the Nadal criterion), on the applied window width.

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