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Maglev vehicle/guideway vertical interaction model. (a) Model of maglev vehicle on at-grade short beam; (b) Maglev vehicle/elevated-guideway model.
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Summary The research and development (R & D) of maglev technology had made a great progress in China since the early 1980s. Especially, a 35 km-long Shanghai high-speed maglev railway employing the German Transrapid system began to be constructed on March 1, 2001. Based on the Transrapid system, the paper develops a 10-degree-of-freedom model of ma...
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The existing international bibliography -German, French, AREMA methods- includes various methods for a realistic estimation of loads on track superstructure and the reactions/actions on the sleepers. The magnitude of loads derived from these formulas could not justify the systematic appearance of cracks at 60% of the sleepers in the Greek network....
Trains and railways affect our lives in a variety of ways we may not always realize. Passengers traveling across country get there safely and quickly with the use of train and railway system. In many countries around the world, the train is a necessary form of transportation as the communities are very far apart and though there are rough roads and...
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... There are two major forms of magnetic levitation, utilizing either the attractive force between iron-core electromagnets and ferromagnetic rails or the repulsive force between superconductivity magnets and induced electric currents in conductive guideway components [2]. The former is known as electromagnetic suspension (EMS), and the latter is called electrodynamic suspension (EDS). ...
As a novel form of railway transportation, maglev transportation has the advantages of a better curve negotiation ability and grade ability and lower noise and vibration than traditional urban wheel–rail transportation. Thus, it is suitable for use in urban public transportation. However, the levitation of the widely utilized electromagnet suspension (EMS) system relies on continuously active suspension force adjustment, which gives it vehicle–track-coupled vibration characteristics different to those of the traditional wheel–track transportation system. Despite many research studies focusing on maglev vehicle–track coupling vibration, the environmental vibration influences associated with the running of maglev trains are still unclear. When the vibration propagates to the surroundings beyond certain thresholds, it may lead to various vibration serviceability problems. Practical test results on the environmental vibration induced by maglev transportation are still not enough to generate convincing vibration propagation and attenuation laws. In this research, a series of in situ tests were carried out around the Shanghai maglev line; the results show that the viaduct bridge is helpful in reducing environmental vibration, and an empirical formula was proposed to predict the effect of viaduct column height. Due to the ground wave superposition, a vibration-amplifying zone was also found about 10 m away from the maglev line, in which the vibration magnitude was strong enough to be perceived by the surrounding occupants.
... The magnetic levitation module's linear and angular acceleration are caused by forces that arise during the passage of the vehicle [49]. Non-linear non-uniformities appear on the guideway's surface as a result of the suspension system's reaction to accelerations in the discrete system during travel [50]. The mechanical model of the guideway is described in scientific journals as being represented by a beam with a constant crosssection resting on an elastic basis [51]. ...
A mathematical model is presented for the slide as a continuous system along which a moving force from the capsule moves, and the capsule as a discrete system. The displacements of the magnet elements were determined by performing simulations. Simulations were carried out with ANSYS software using FEM (Finite Element Method) calculations. The results will determine the nature of the capsule's movement. The results of the simulations were used to study stability in a technical and stochastic sense (Lyapunov criterion) for non-linear systems, taking into account the conditions present in the magnet and guide element system. Transverse displacements of the electromagnets were used in the technical stochastic stability study. The paper also presents a method for determining technical and stochastic stability for the Hyperloop vehicle for different speeds and taking into account the displacements of the levitation set. The probability of unsteady Hyperloop motion was then determined.
... 1 The first commercial maglev line in the world was built in 2003, connecting Shanghai Pudong Airport to Longyang Railway Station. 2 Recently, China launched a high-speed maglev transport system at 600 km/h, demonstrating the possibility of further commercialization of high-speed maglev trains. 3 As train speed increases, increasing attention has been paid to the dynamic performance of the maglev vehicle when it runs on a guideway. ...
The dynamic performance of high-speed maglev trains, a next-generation rapid transit system, has received continuous attention in recent years. In this study, a dynamic reliability analysis method for a high-speed maglev train–guideway coupled system was proposed. First, a refined model of the maglev vehicle–bridge interaction system was established, where the vehicle subsystem was simulated as a rigid body-spring-damper model with 101 degrees of freedom. The guideway subsystem was simulated as a finite element model, and these two subsystems were coupled as an entire system through a magnet–rail interaction model with a proportional-derivative (PD) controller. Second, a dimension-reduction method for the simulation of representative samples of track irregularities was developed, and thus the number of random variables in the system was reduced to four. Finally, an efficient method for the calculation of the dynamic reliability of a maglev train–guideway coupled system was proposed using the probability density evolution method-based equivalent extreme value principle. With numerical examples, the accuracy of the maglev train–guideway interaction model was verified by comparing it with field measurement data from the Shanghai high-speed maglev line. The accuracy of the proposed dynamic reliability analysis method was confirmed by comparing three types of results, that is, the mean value time-history curve, the probability density function, and the cumulative distribution function of extreme values, obtained by the Monte Carlo method. Finally, the dynamic reliability of the running safety and stability of the maglev vehicle at a speed of 430 km/h and the variation laws of the dynamic reliabilities with train speed were examined in detail.
... Many researchers have studied the dynamics problems involving the train-guideway dynamic interactions, running safety and ride comfort of maglev trains. The vehicle system dynamics models are developed from multi-rigid-body system with only vertical motions [2][3][4][5] or vertical/ lateral/longitudinal coupling motions [6][7][8][9][10] to flexible multibody system [11][12][13], and the description for connections between the vehicle components is promoted to capture strong nonlinearity. The dynamics models of guideway system are improved from simple continuous Bernoulli-Euler beam with only vertical vibrations [2][3][4][5] to beams with considering discontinuity, spatial motions and/or detailed cross-section [7][8][9][10]13,14]. ...
... The vehicle system dynamics models are developed from multi-rigid-body system with only vertical motions [2][3][4][5] or vertical/ lateral/longitudinal coupling motions [6][7][8][9][10] to flexible multibody system [11][12][13], and the description for connections between the vehicle components is promoted to capture strong nonlinearity. The dynamics models of guideway system are improved from simple continuous Bernoulli-Euler beam with only vertical vibrations [2][3][4][5] to beams with considering discontinuity, spatial motions and/or detailed cross-section [7][8][9][10]13,14]. The electromagnet forces are simulated by proportionalderivative controllers [8][9][10], replacing linear/nonlinear springdampers [2][3][4][5] to nonlinear spatial ones. ...
... The dynamics models of guideway system are improved from simple continuous Bernoulli-Euler beam with only vertical vibrations [2][3][4][5] to beams with considering discontinuity, spatial motions and/or detailed cross-section [7][8][9][10]13,14]. The electromagnet forces are simulated by proportionalderivative controllers [8][9][10], replacing linear/nonlinear springdampers [2][3][4][5] to nonlinear spatial ones. With the refinement of these models and the developments of computational techniques, it is more realistic and efficient to study the dynamics problems due to moving maglev trains. ...
... Talukdar and Talukdar [12] summarized a method of modeling and simulating maglev vehicle-guide track by using SIMULINK software, studied the influence of vehicle speed and track irregularity on vehicle performance, analyzed the dynamic response of vehicle-guide track, and optimized suspension parameters. Based on Transrapid system, Zhao and Zhai [13] developed a 10-degree-of-freedom model of maglev vehicle running at constant speed on three types of guide tracks; discussed the construction of track random irregularity, simulated based on this, obtained the response of maglev train and calculated the stability; used direct time integration method and discrete fast Fourier transform (DFFT) to study the random response of maglev vehicle-track system, and obtained the resonance frequency of vehicle body acceleration. ...
... Early studies used simplified analytical models to examine the dynamic interaction of the maglev system. The guideway was also generally treated as a simple or continuous beam supported by the mode superposition method, and simplified vehicle models were developed without considering the suspension control [9][10][11][12][13][14][15][16][17][18][19]. Following the improved simulation of the maglev vehicle and electromagnet interaction, more complicated vehicle/guideway models such as two-dimensional [15][16][17][18][19] and threedimensional vehicle models [20][21][22] were developed that consider the proportional-integral-derivative (PID) control [15] or LQG control theory [13]. ...
... The guideway was also generally treated as a simple or continuous beam supported by the mode superposition method, and simplified vehicle models were developed without considering the suspension control [9][10][11][12][13][14][15][16][17][18][19]. Following the improved simulation of the maglev vehicle and electromagnet interaction, more complicated vehicle/guideway models such as two-dimensional [15][16][17][18][19] and threedimensional vehicle models [20][21][22] were developed that consider the proportional-integral-derivative (PID) control [15] or LQG control theory [13]. These models have been used to investigate more complicated dynamic interactions of maglev systems including the effects of irregularities [17,19], resonant conditions [15], ground settlement [23] and cross-wind loads [24]. ...
... The EMS maglev vehicle has advantages of high operational safety, good ride comfort, low vibration and noise, better curve negotiation and climbing ability. In recent years, the world has made rapid developments with respect to these technologies [1][2][3]. But in almost every lowspeed maglev line operation, there are violent vehicleguideway (switch) coupling vibration phenomena, and in serious cases, these can lead to electromagnet and rail collisions and may even lead to levitation instability [4,5]. ...
... Based on the previous analysis, the PID levitation control model accounting for the LGF time delay (2) is constructed in Simulink; the levitation gap and levitation electromagnet force are used as the input and output of Simpack and Simulink; and the Simat interface is used to realize the co-simulation analysis. The German lowdisturbance track irregularity is used to model external excitation on the maglev vehicle system [1]. The analysis focuses on the coil current and levitation gap at the first control point on the right first levitation module, the vertical acceleration responses of the first levitation frame, and the carbody. ...
EMS maglev train uses the active control system to maintain the levitation stability, time delay is widespread in control system. However, the existing maglev dynamics studies rarely consider the effect of time delay, so these analysis results cannot directly guide the engineering design. This paper starts from a theoretical analysis of the levitation stability of a single electromagnet levitation system to obtain the theoretical critical value for the time delay. Then the model is gradually extended to a complete vehicle model and a vehicle-girder coupling dynamics model to find the time delay engineering critical values for the complex coupling system. In order to seek ways to reduce the influence of time delay on the dynamic responses, this paper analyzes the influence regularities of the running speed and control parameters on the dynamic response under the effect of time delay. The result shows that the theoretical critical value of the time delay is equal to the ratio of the differential coefficient and proportional coefficient of the PID controller. For a complex maglev system, the engineering critical value is less than the theoretical critical value. Higher running speeds lead to time delay having a more obvious effect on the maglev system’s dynamic responses. Selecting the smaller proportional coefficient and appropriate differential coefficient for the levitation control system can expand the stability region and reduce the influence of time delay on the maglev system. This analysis is helpful and meaningful to the understanding of the EMS vehicle system stability, and helpful to explore the reason of violent coupled vibration in actual engineering.
... Over the last two decades, studies on the dynamic performance of train-track systems for maglev trains have contributed significantly to the fulfillment of low-medium-speed maglev transportation. In consideration of rail irregularities, Zhao and Zhai [8] built a 10-DOF model of a maglev train to study the maglev train responses and dynamic indexes affecting riding comfort underlying the German maglev express train system. Zheng et al. [9] optimized the maglev train by transforming it into a five-degree-of-freedom model with two-stage suspensions, and simulated the coupled dynamic responses of the system. ...
In order to reduce the impact of noise on the environment and reduce the dissipation of useless energy of traction motors, this study analyzed the noise of a traction motor by detecting the vibration acceleration of the suspension frame. Field tests were conducted to measure the traction noise and suspension frame vibration in a commercially operational medium- and low-speed maglev train. The tests showed that as the train accelerates, the sound pressure grows overall, but the increase becomes smaller at each test speed. The speed of the maglev train is closely correlated with the vibrations of the suspension frame in lateral/vertical directions. The dominant frequency of traction motor noise is basically consistent with that of suspension frame vibration acceleration, showing that the suspension frame vibration is the main reason for high-frequency noise in the operation of low–medium-speed maglev trains.
... [6][7][8] Additionally, the resonance between maglev vehicles and the slender guideway was simulated and measured on a test track, especially under standing levitation and low-speed operating conditions. 9,10 In China, maglev train dynamics have been studied extensively since 2000, [11][12][13][14][15][16][17] when the Shanghai Highspeed Maglev Line Project was approved and implemented. Subsequently, several medium-low speed maglev test vehicles were developed in China during the¯rst decade of the 21st century, whose dynamic performances were predicted and evaluated by numerical studies. ...
With the ongoing development and deployment of medium-low speed maglev vehicles in China, it has become common to increase operational speeds from 100km/h up to 140km/h or even 160km/h, necessitating further studies and simulation models to understand the implications of these changes. This paper analyzes medium-speed maglev vehicle-track-girder coupling dynamic performance at a speed of 160km/h. First, a field dynamics experiment is carried out on the Changsha Maglev Express with a running speed of 80–140km/h. Then we introduce the distributed coupling simulation platform for maglev transportation system (MTS-DCSP) and the vehicle-track-girder coupling model, taking into account the complex vehicle structure, the guideway structure, and the Proportion Integral Differential (PID) levitation control system. Together, this platform and model can conduct a simulation of the complete process at scale and at all degrees of freedom to obtain accurate results. Our analysis of the results gives an accurate portrayal of the coupling dynamics properties and validates the coupling model. The results from the field experiments together with the coupling simulation demonstrate that the medium-speed maglev train can operate safely and stably within the range of 140–160km/h. While at 140km/h, however, the Sperling ride quality index (RQI) is about 2.5, which is within the Excellent grade range, at a speed of 160km/h, the Sperling ride quality index can increase to as high as 2.74, which is a grade of Good. Therefore, it is necessary to optimize the parameters of the secondary suspension system to improve the ride comfort of the maglev vehicle at 160km/h.
... High-speed maglev transportation has attracted more and more attention with the advantages of high speed, low energy consumption, strong climbing ability and high comfort [8,15]. These features make the high-speed maglev line have excellent competitiveness in the transportation system between cities with medium and long distance. ...
PurposeThe existing integrated structural form of track and beam for maglev transportation leads to the relative large complexity in manufacture and construction. And the height alignment adjustment of the track surface is hard to realized to maintain the favourable running condition in the daily operation. To avoid these shortcomings, a new structural form of separated track and beam for high-speed maglev is proposed and its dynamic characteristics under moving train are studied.Methods
The proposed separated track beam structure contains the prefabricated concrete simply supported box section beam, track bearing beam, track bearing platform, prefabricated track slab, and anchor fastener system. Its finite element model is established first. Then the maglev train is modelled in a dynamic way. Introducing the electromagnetic force with the typical PID control rule, the coupled dynamic system of the high-speed maglev train and the bridge is set up through the inner system iteration method. In the dynamic system, track irregularity is fully considered.ResultsThe dynamic amplification factor of the new structure with 3.5 m-high beam can be controlled within 1.3. The ride comfort can also be well controlled. The dynamic responses of the track, and the maglev gap can be accepted.Conclusion
The ride comfort of the high-speed maglev train can be further control through increasing the beam height, reducing the beam span, or improving the performance of the secondary suspension system of the train. The end deformation of the track slabs is not the core control parameter.
