Purpose–High-speed maglev technology can address the issues of adhesion,friction,vibration and highspeed current collection in traditional wheel-rail systems,making it an important direction for the future developmen...Purpose–High-speed maglev technology can address the issues of adhesion,friction,vibration and highspeed current collection in traditional wheel-rail systems,making it an important direction for the future development of high-speed rail technology.Design/methodology/approach–This paper elaborates on the demand and significance of developing high-speed maglev technology worldwide and examines the current status and technological maturity of several major high-speed maglev systems globally.Findings–This paper summarizes the challenges in the development of high-speed maglev railways in China.Based on this analysis,it puts forward considerations for future research on high-speed maglev railways.Originality/value–This paper describes the development status and technical maturity of several major high-speed maglev systems in the world for the first time,summarizes the existing problems in the development of China’s high-speed maglev railway and on this basis,puts forward the thinking of the next research of China’s high-speed maglev railway.展开更多
The safety and stability of high-speed maglev trains traveling on viaducts in crosswinds critically depend on their aerodynamic characteristics.Therefore,this paper uses an improved delayed detached eddy simulation(ID...The safety and stability of high-speed maglev trains traveling on viaducts in crosswinds critically depend on their aerodynamic characteristics.Therefore,this paper uses an improved delayed detached eddy simulation(IDDES)method to investigate the aerodynamic features of high-speed maglev trains with different marshaling lengths under crosswinds.The effects of marshaling lengths(varying from 3-car to 8-car groups)on the train’s aerodynamic performance,surface pressure,and the flow field surrounding the train were investigated using the three-dimensional unsteady compressible Navier-Stokes(N-S)equations.The results showed that the marshaling lengths had minimal influence on the aerodynamic performance of the head and middle cars.Conversely,the marshaling lengths are negatively correlated with the time-average side force coefficient(CS)and time-average lift force coefficient(Cl)of the tail car.Compared to the tail car of the 3-car groups,the CS and Cl fell by 27.77%and 18.29%,respectively,for the tail car of the 8-car groups.It is essential to pay more attention to the operational safety of the head car,as it exhibits the highest time average CS.Additionally,the mean pressure difference between the two sides of the tail car body increased with the marshaling lengths,and the side force direction on the tail car was opposite to that of the head and middle cars.Furthermore,the turbulent kinetic energy of the wake structure on the windward side quickly decreased as marshaling lengths increased.展开更多
Purpose–This study aims to explore the formation mechanism of aerodynamic noise of a high-speed maglev train and understand the characteristics of dipole and quadrupole sound sources of the maglev train at different ...Purpose–This study aims to explore the formation mechanism of aerodynamic noise of a high-speed maglev train and understand the characteristics of dipole and quadrupole sound sources of the maglev train at different speed levels.Design/methodology/approach–Based on large eddy simulation(LES)method and Kirchhoff–Ffowcs Williams and Hawkings(K-FWH)equations,the characteristics of dipole and quadrupole sound sources of maglev trains at different speed levels were simulated and analyzed by constructing reasonable penetrable integral surface.Findings–The spatial disturbance resulting from the separation of the boundary layer in the streamlined area of the tail car is the source of aerodynamic sound of the maglev train.The dipole sources of the train are mainly distributed around the radio terminals of the head and tail cars of the maglev train,the bottom of the arms of the streamlined parts of the head and tail cars and the nose tip area of the streamlined part of the tail car,and the quadrupole sources are mainly distributed in the wake area.When the train runs at three speed levels of 400,500 and 600 km$h1,respectively,the radiated energy of quadrupole source is 62.4%,63.3%and 71.7%,respectively,which exceeds that of dipole sources.Originality/value–This study can help understand the aerodynamic noise characteristics generated by the high-speed maglev train and provide a reference for the optimization design of its aerodynamic shape.展开更多
With the quasi-natural experiment of the launching of high-speed railways in Chinese cities,this paper empirically investigated the effects of the upgrade of the transportation infrastructure on the site selection of ...With the quasi-natural experiment of the launching of high-speed railways in Chinese cities,this paper empirically investigated the effects of the upgrade of the transportation infrastructure on the site selection of polluting enterprises.We found that although the launching of a high-speed railway generally has a negative impact on the siting of polluting enterprises:(i)While there was a significant decrease in polluting enterprises of a private and other nature,the reduction in overseas-funded and state-owned enterprises was insignificant;(ii)while the launching of a high-speed railway greatly restrained the entry of polluting enterprises in the eastern region,large cities and more developed cities,this was followed by the movement of more polluting enterprises to the central and western regions,small and medium-sized cities and less developed cities;(iii)there was a significant decrease in polluting enterprises in environmentally conscious cities after the launching of a high-speed railway.This paper also found that infrastructure upgrade may influence the siting of polluting enterprises through the following:Environmental cleanness,factor concentration and spatial integration.Government authorities and market entities should be fully aware of and attach great importance to how the transportation infrastructure influences the site selection of businesses,as this is of great significance for China’s regional development planning,local business climate and investment planning,environmental protection,and other related policymaking initiatives.展开更多
In recent ten years, the rapid development of China high-speed railway is called "China miracle", and it not only provides great convenience for people's daily life trip, but also greatly promotes the ec...In recent ten years, the rapid development of China high-speed railway is called "China miracle", and it not only provides great convenience for people's daily life trip, but also greatly promotes the economic development. However, the annual spring transportation in the special period is still a great challenge to high-speed railway transportation, and this paper analyzes the high-speed railway ticket for spring transportation from the perspective of microeconomics, and then thinks for the solution. This paper specifically analyzes the problem that demand exceeds supply for high-speed railway ticket by using the theories of the demand elasticity of supply and demand and the influence of price on supply and demand, monopoly markets. In addition, opportunity cost, incomplete information and other economic principles are used to think about the theoretical reasons for the difficulty of buying tickets during the spring transportation. I have given my understanding for the two problems owned by China spring transportation, and the corresponding countermeasures and suggestions. For example, speed up the development of substitutes and carry out the mechanism of price fluctuation;In the ticket refunding mechanism, this paper boldly conceives the method to relieve the pressure through a reasonable and scientific ticket refunding mechanism. Finally, this paper starts from the source and find the key point to solve the problem of spring transportation in China by breaking the urban-rural dual structure. Hereafter the final conclusion was drawn: Although there are some problems to cope with the spring transport for the current China high-speed railway, it is believed that in the near future, the difficulty of buying a ticket in spring transportation will no longer hinder the homecoming of wanderers.展开更多
In this study, the intrinsic mechanism of aerodynamic effects on the motion stability of a high-speed maglev system was investigated. The concept of a critical speed for maglev vehicles considering the aerodynamic eff...In this study, the intrinsic mechanism of aerodynamic effects on the motion stability of a high-speed maglev system was investigated. The concept of a critical speed for maglev vehicles considering the aerodynamic effect is proposed. The study was carried out based on a single magnetic suspension system, which is convenient for proposing relevant concepts and obtaining explicit expressions. This study shows that the motion stability of the suspension system is closely related to the vehicle speed when aerodynamic effects are considered. With increases of the vehicle speed, the stability behavior of the system changes. At a certain vehicle speed,the stability of the system reaches a critical state, followed by instability. The speed corresponding to the critical state is the critical speed. Analysis reveals that when the system reaches the critical state, it takes two forms, with two critical speeds, and thus two expressions for the critical speed are obtained. The conditions of the existence of the critical speed were determined, and the effects of the control parameters and the lift coefficient on the critical speed were analyzed by numerical analysis. The results show that the first critical speed appears when the aerodynamic force is upward,and the second critical speed appears when the aerodynamic force is downward. Moreover, both critical speeds decrease with the increase of the lift coefficient.展开更多
A novel maglev transportation system was proposed for large travel range ultra precision motion.The system consists of a levitation subsystem and a propulsion subsystem.During the propulsion subsystem driving the movi...A novel maglev transportation system was proposed for large travel range ultra precision motion.The system consists of a levitation subsystem and a propulsion subsystem.During the propulsion subsystem driving the moving platform along the guideway,the levitation subsystem uses six pairs of electromagnets to steadily suspend the moving platform over the guideway.The model of the levitation system,which is a typical nonlinear multi-input multi-output coupling system and has many inner nonlinear coupling characteristics,was deduced.For testifying the model,the levitation mechanism was firstly controlled by proportional-integral-differential(PID) control,and then a lot of input-output data were collected for model parameter identification.The least-square parameter identification method was used.The identification results prove that the model is feasible and suitable for the real system.展开更多
High speed maglev train has become a new non-contact transportation mode mainly studied in recent years because of its non-sticking and high speed characteristics.Firstly,the finite element model of the long stator li...High speed maglev train has become a new non-contact transportation mode mainly studied in recent years because of its non-sticking and high speed characteristics.Firstly,the finite element model of the long stator linear synchronous motor(LSM)is established based on the structure of the test prototype.After calculation,it is compared with the experimental data and verified.On this basis,a field-circuit coupling model based on inverter circuit is established,and the influence of carrier wave ratio change on the output characteristics of LSM is calculated and analyzed.Finally,the filter circuit is introduced into the field-circuit coupling model,and the influence of the filter circuit on the output characteristics of the LSM is compared and analyzed.展开更多
Purpose-This paper aims to provide top-level design and basic platform for intelligent application in China high-speed railway.Design/methodology/approach-Based on the analysis for the future development trends of wor...Purpose-This paper aims to provide top-level design and basic platform for intelligent application in China high-speed railway.Design/methodology/approach-Based on the analysis for the future development trends of world railway,combined with the actual development needs in China high-speed railway,The definition and scientific connotation of intelligent high-speed railway(IHSR)are given at first,and then the system architecture of IHSR are outlined,including 1 basic platform,3 business sectors,10 business fields,and 18 innovative applications.At last,a basic platform with cloud edge integration for IHSR is designed.Findings-The rationality,feasibility and implementability of the system architecture of IHSR have been verified on and applied to the Beijing-Zhangjiakou high-speed railway,providing important support for the construction and operation of the world’s first IHSR.Originality/value-This paper systematically gives the definition and connotation of the IHSR and put forward the system architecture of IHSR for first time.It will play the most important role in the design,construction and operation of IHSR.展开更多
In this paper, the roles of infrastructure development and transportation coordination for Northeast Asian economic cooperation are discussed. It would be necessary to establish an efficient transportation network as ...In this paper, the roles of infrastructure development and transportation coordination for Northeast Asian economic cooperation are discussed. It would be necessary to establish an efficient transportation network as soon as possible. "Hub-and-Spoke"transportation system and China-Korean peninsula railway container transportation system might be more significant for regional economic cooperation.展开更多
Evacuated tube transportation(ETT) will be one of the ultra-large-scale vacuum application areas.This paper lists some key vacuum technology issues in ETT:(1) how to construct ultra-large-scale vacuum chamber with low...Evacuated tube transportation(ETT) will be one of the ultra-large-scale vacuum application areas.This paper lists some key vacuum technology issues in ETT:(1) how to construct ultra-large-scale vacuum chamber with lower cost and high reliability,(2) how to evacuate gas out of the ETT tube in short time,(3) how to release heat or reduce temperature in the vacuum tube,(4) how to avoid vacuum discharge,(5) how to make vehicles with airproof shells and life support system,and(6) how to detect leaks and find leak positions efficiently.At the same time,some solutions are proposed.展开更多
The super-high speed high temperature superconductor (HTS) maglev evacuated tube transport (ETT) is a promising transport mode for the future. As a key component of the HTS maglev vehicle, the permanent magnet guide-w...The super-high speed high temperature superconductor (HTS) maglev evacuated tube transport (ETT) is a promising transport mode for the future. As a key component of the HTS maglev vehicle, the permanent magnet guide-ways (PMGs) with different geometrical configurations and iron yoke widths are analyzed by finite element method (FEM). The levitation force of a single onboard HTS maglev device over the designed PMG at different field cooling heights (FCH) is measured by magnetic levitation measurement system. Based on the designed PMG and experimental results, a preliminary scheme of subterranean super-high speed HTS maglev ETT is described in this paper. The HTS maglev ETT is mainly composed of an evacuated tube, HTS maglev vehicle, PMG, propulsion system, station, emergency rescue system, etc. In addition, a subterranean tube that consists of foundation tube and vacuum airproof layer is introduced. In order to convert the stress caused by the air pressure difference between inside and outside of the vehicle, a multi-circular vehicle body is designed. The vehicle is driven by a linear motor propulsion system under the control of a ground controlling system. The scheme of long-distance super-high speed passenger transportation is accomplished by the connection of different vehicles.展开更多
High-speed Maglev is a cutting-edge technology brought back into the focus of research by plans of the Chinese government for the development of a new 600 km/h Maglev train.A Chinese‐German cooperation with industria...High-speed Maglev is a cutting-edge technology brought back into the focus of research by plans of the Chinese government for the development of a new 600 km/h Maglev train.A Chinese‐German cooperation with industrial and academic partners has been established to pursue this ambitious goal and bring together experts from multiple disciplines.This contribution presents the joint work and achievements of CRRC Qingdao Sifang,thyssenkrupp Transrapid,CDFEB,and the ITM of the University of Stuttgart,regarding research and development in the field of high‐speed Maglev systems.Furthermore,an overview is given of the historical development of the Transrapid in Germany,the associated development of dynamical simulation models,and recent developments regarding high-speed Maglev trains in China.展开更多
High-speed maglev trains will play an important role in the high-speed transportation system in the near future.However,under the conditions of strong magnetic fields and continuous operation,the actuators of the high...High-speed maglev trains will play an important role in the high-speed transportation system in the near future.However,under the conditions of strong magnetic fields and continuous operation,the actuators of the high-speed maglev train suspension system are prone to lose partial effectiveness,which makes the suspension control problem challenging.In addition,most existing fault-tolerant control(FTC)methods for suspension systems require linearization around the equilibrium points during the controller design or stability analysis.Therefore,from a practical perspective,this study presents a novel nonlinear FTC strategy with adaptive compensation for high-speed maglev train suspension systems.First,a nonlinear dynamic model of the suspension system based on join-structure is established and the actuator failures are described.Then,a nonlinear fault-tolerant suspension control law with an adaptive update law is designed to achieve stable suspension against partial actuator failure.The Lyapunov theory and extended Barbalat lemma are utilized to rigorously prove the closed-loop asymptotic stability even if there is partial actuator failure,without any approximation to the original nonlinear dynamics.Finally,hardware experimental results are included to demonstrate the effectiveness of the proposed approach.展开更多
Land-use efficiency is low for the urban agglomeration of China.High-speed transportation construction has been an important factor driving land use change.It is criti?cally importa nt to explore the spatial relati on...Land-use efficiency is low for the urban agglomeration of China.High-speed transportation construction has been an important factor driving land use change.It is criti?cally importa nt to explore the spatial relati on ship between the high-speed transportation su?periority degree and land-use efficie ncy.We built a model to evaluate the ben efits of con?venient high-speed transportation using the relative density of highways and the distanee from high-speed rail stations and airports as a metric.We used 42 coun ties of the Shan dong Peninsula urban agglomeration as an example.Land?use efficiency was calculated by a DEA model with capital,labor,economic ben efits and envir on mental ben efits as input and output factors.We examined the spatial relati on ships betwee n high-speed tran sport superiority degree and land-use efficiency and obtained the following results.First,there are significant spatial differe nces in the relati on ships betwee n the high-speed transportati on superiority degree and land-use efficiency.Taking the two major cities of Jinan and Qingdao as the hubs,the core surrounding counties show significant spatial relationship between land-use efficiency and the high-speed transportation superiority degree.Spatial correlation declines as the distance from the hubs in creases.Land-use efficiency is less tha n high-speed tran sportation convenience in areas along the transportation trunks that are distant from the hub cities.Correlation is low in areas that are away from both hub cities and transportation trunk routes.Second,high-speed transportation has a positive relationship with land?use efficiency due to the mechanism of element agglomeration exogenous growth.Third,high-speed transportation facilitates the flow of goods,services and tech no logies between core cities and peripheral cities as space spillover(the hub effect).This alters the spatial pattern of regional land-use efficiency.Fin ally,the short-board effect caused by decreased high-speed tran sport corn struction can be balaneed by highway construction and the proper node layouts of high-speed rail stations and airports,resulting in a well-balaneed spatial pattern of land?use efficiency.展开更多
At present, most of China's railway hubs are developed to be transportation complexes, with some problems like unsmooth traffic circulation, mixed but disordered functions, separated spaces, etc. In high-speed rai...At present, most of China's railway hubs are developed to be transportation complexes, with some problems like unsmooth traffic circulation, mixed but disordered functions, separated spaces, etc. In high-speed rail era, high-speed railway hubs should be regarded as the catalyst to promoted urban development. The mode of urban complex should be developed, to closely connect the railway hub and the surrounding area within walking distance, so as people could get to their destinations in the most convenient way. Furthermore, it would strengthen people's aggregation, thus to bring about larger scale urban development by the successful development of urban complex.展开更多
The dynamic interaction between maglev vehicle and three-span continuous guideway is discussed. With the consideration of control system, the dynamic interaction model has been developed. Numerical simulation has been...The dynamic interaction between maglev vehicle and three-span continuous guideway is discussed. With the consideration of control system, the dynamic interaction model has been developed. Numerical simulation has been performed to study dynamic characteristics of the guideway. The results show that bending rigidity, vehicle speed, span ratio and primary frequency all have important influences on the dynamic characteristics of the guideway and there is no distinct trend towards resonance vibration when f1/(v/l) equals 1.0. The definite way is to control impact coefficient and acceleration of the guideway. The conclusions can serve the design of high-speed maglev three-span continuous guideway.展开更多
The dynamic interaction between moving vehicles and two-span continuous guideway was discussed. With the consideration of the magnetic levitation system,the maglev vehicle/guideway dynamic interaction model was develo...The dynamic interaction between moving vehicles and two-span continuous guideway was discussed. With the consideration of the magnetic levitation system,the maglev vehicle/guideway dynamic interaction model was developed.Numerical simulation was performed to understand dynamic characteristics of the guide- way used in practice.The results show that vehicle speed,span length and primary frequency of the guideway have an important influence on the dynamic responses of the guideway and there is no distinct trend towards resonance vibration when f_1 equals 1.0.The definite way is to control the impact coefficient and acceleration of the guideway.The conclusions can serve the design of high speed maglev guideway.展开更多
基金This paper was supported by the funding of Strategic research and consulting project of Chinese Academy of Engineering(Grant No.2022-XBZD-20).
文摘Purpose–High-speed maglev technology can address the issues of adhesion,friction,vibration and highspeed current collection in traditional wheel-rail systems,making it an important direction for the future development of high-speed rail technology.Design/methodology/approach–This paper elaborates on the demand and significance of developing high-speed maglev technology worldwide and examines the current status and technological maturity of several major high-speed maglev systems globally.Findings–This paper summarizes the challenges in the development of high-speed maglev railways in China.Based on this analysis,it puts forward considerations for future research on high-speed maglev railways.Originality/value–This paper describes the development status and technical maturity of several major high-speed maglev systems in the world for the first time,summarizes the existing problems in the development of China’s high-speed maglev railway and on this basis,puts forward the thinking of the next research of China’s high-speed maglev railway.
基金supported by Wuyi University Hong Kong and Macao Joint Research and Development Fund(GrantsNos.2021WGALH15,2019WGALH17,2019WGALH15)the National Natural Science Foundation of China-Guangdong Joint Fund(GrantsNo.2019A1515111052)+2 种基金the National Natural Science Foundation of China(Grant No.52202426)a grant from the Research Grants Council(RGC)of the Hong Kong Special Administrative Region(SAR),China(Grants No.15205723)a grant from the Hong Kong Polytechnic University(Grant No.P0045325).
文摘The safety and stability of high-speed maglev trains traveling on viaducts in crosswinds critically depend on their aerodynamic characteristics.Therefore,this paper uses an improved delayed detached eddy simulation(IDDES)method to investigate the aerodynamic features of high-speed maglev trains with different marshaling lengths under crosswinds.The effects of marshaling lengths(varying from 3-car to 8-car groups)on the train’s aerodynamic performance,surface pressure,and the flow field surrounding the train were investigated using the three-dimensional unsteady compressible Navier-Stokes(N-S)equations.The results showed that the marshaling lengths had minimal influence on the aerodynamic performance of the head and middle cars.Conversely,the marshaling lengths are negatively correlated with the time-average side force coefficient(CS)and time-average lift force coefficient(Cl)of the tail car.Compared to the tail car of the 3-car groups,the CS and Cl fell by 27.77%and 18.29%,respectively,for the tail car of the 8-car groups.It is essential to pay more attention to the operational safety of the head car,as it exhibits the highest time average CS.Additionally,the mean pressure difference between the two sides of the tail car body increased with the marshaling lengths,and the side force direction on the tail car was opposite to that of the head and middle cars.Furthermore,the turbulent kinetic energy of the wake structure on the windward side quickly decreased as marshaling lengths increased.
基金The research was supported by the National Key Research and Development Program(Grant No.2020YFA0710903)the Financial Funding Project for Central Colleges and Universities(Grant No.202045014)the Science and Technology Research and Development Program of China State Railway Group Co.,Ltd.(Grant No.P2019J008).
文摘Purpose–This study aims to explore the formation mechanism of aerodynamic noise of a high-speed maglev train and understand the characteristics of dipole and quadrupole sound sources of the maglev train at different speed levels.Design/methodology/approach–Based on large eddy simulation(LES)method and Kirchhoff–Ffowcs Williams and Hawkings(K-FWH)equations,the characteristics of dipole and quadrupole sound sources of maglev trains at different speed levels were simulated and analyzed by constructing reasonable penetrable integral surface.Findings–The spatial disturbance resulting from the separation of the boundary layer in the streamlined area of the tail car is the source of aerodynamic sound of the maglev train.The dipole sources of the train are mainly distributed around the radio terminals of the head and tail cars of the maglev train,the bottom of the arms of the streamlined parts of the head and tail cars and the nose tip area of the streamlined part of the tail car,and the quadrupole sources are mainly distributed in the wake area.When the train runs at three speed levels of 400,500 and 600 km$h1,respectively,the radiated energy of quadrupole source is 62.4%,63.3%and 71.7%,respectively,which exceeds that of dipole sources.Originality/value–This study can help understand the aerodynamic noise characteristics generated by the high-speed maglev train and provide a reference for the optimization design of its aerodynamic shape.
基金supported by Major Project of the National Social Science Fund of China (NSSFC)“Study on Making Substantive Progress in China’s Long-range Goal of Common Prosperity by 2035”(Grant No. 21ZDA005)General Project of the National Natural Science Foundation of China (NSFC)“Trade Partners, Commodity Structure and Environmental Pollution”(Grant No. 72073013)+1 种基金General Project of the National Natural Science Foundation of China (NSFC)“Village Democratic Governance and China’s Processing Trade Transition”(Grant No. 71773007)support from the Shanghai Yangtze River Delta Financial Service and Collaborative Innovation Center for Sci-tech Innovation Industries。
文摘With the quasi-natural experiment of the launching of high-speed railways in Chinese cities,this paper empirically investigated the effects of the upgrade of the transportation infrastructure on the site selection of polluting enterprises.We found that although the launching of a high-speed railway generally has a negative impact on the siting of polluting enterprises:(i)While there was a significant decrease in polluting enterprises of a private and other nature,the reduction in overseas-funded and state-owned enterprises was insignificant;(ii)while the launching of a high-speed railway greatly restrained the entry of polluting enterprises in the eastern region,large cities and more developed cities,this was followed by the movement of more polluting enterprises to the central and western regions,small and medium-sized cities and less developed cities;(iii)there was a significant decrease in polluting enterprises in environmentally conscious cities after the launching of a high-speed railway.This paper also found that infrastructure upgrade may influence the siting of polluting enterprises through the following:Environmental cleanness,factor concentration and spatial integration.Government authorities and market entities should be fully aware of and attach great importance to how the transportation infrastructure influences the site selection of businesses,as this is of great significance for China’s regional development planning,local business climate and investment planning,environmental protection,and other related policymaking initiatives.
文摘In recent ten years, the rapid development of China high-speed railway is called "China miracle", and it not only provides great convenience for people's daily life trip, but also greatly promotes the economic development. However, the annual spring transportation in the special period is still a great challenge to high-speed railway transportation, and this paper analyzes the high-speed railway ticket for spring transportation from the perspective of microeconomics, and then thinks for the solution. This paper specifically analyzes the problem that demand exceeds supply for high-speed railway ticket by using the theories of the demand elasticity of supply and demand and the influence of price on supply and demand, monopoly markets. In addition, opportunity cost, incomplete information and other economic principles are used to think about the theoretical reasons for the difficulty of buying tickets during the spring transportation. I have given my understanding for the two problems owned by China spring transportation, and the corresponding countermeasures and suggestions. For example, speed up the development of substitutes and carry out the mechanism of price fluctuation;In the ticket refunding mechanism, this paper boldly conceives the method to relieve the pressure through a reasonable and scientific ticket refunding mechanism. Finally, this paper starts from the source and find the key point to solve the problem of spring transportation in China by breaking the urban-rural dual structure. Hereafter the final conclusion was drawn: Although there are some problems to cope with the spring transport for the current China high-speed railway, it is believed that in the near future, the difficulty of buying a ticket in spring transportation will no longer hinder the homecoming of wanderers.
基金supported by the National Key Research and Development Program of China(Grant 2016YFB1200602)the National Natural Science Foundation of China (Grants 11672306, 51490673)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant XDB22020101)the National Basic Research Program (973 Program) of China (Grant 2014CB046801)the State Key Laboratory of Hydraulic Engineering Simulation and Safety (Tianjin University)
文摘In this study, the intrinsic mechanism of aerodynamic effects on the motion stability of a high-speed maglev system was investigated. The concept of a critical speed for maglev vehicles considering the aerodynamic effect is proposed. The study was carried out based on a single magnetic suspension system, which is convenient for proposing relevant concepts and obtaining explicit expressions. This study shows that the motion stability of the suspension system is closely related to the vehicle speed when aerodynamic effects are considered. With increases of the vehicle speed, the stability behavior of the system changes. At a certain vehicle speed,the stability of the system reaches a critical state, followed by instability. The speed corresponding to the critical state is the critical speed. Analysis reveals that when the system reaches the critical state, it takes two forms, with two critical speeds, and thus two expressions for the critical speed are obtained. The conditions of the existence of the critical speed were determined, and the effects of the control parameters and the lift coefficient on the critical speed were analyzed by numerical analysis. The results show that the first critical speed appears when the aerodynamic force is upward,and the second critical speed appears when the aerodynamic force is downward. Moreover, both critical speeds decrease with the increase of the lift coefficient.
基金Projects(50735007,51005253) supported by the National Natural Science Foundation of ChinaProject(2007AA04Z344) supported by the National High-Tech Research and Development Program of China
文摘A novel maglev transportation system was proposed for large travel range ultra precision motion.The system consists of a levitation subsystem and a propulsion subsystem.During the propulsion subsystem driving the moving platform along the guideway,the levitation subsystem uses six pairs of electromagnets to steadily suspend the moving platform over the guideway.The model of the levitation system,which is a typical nonlinear multi-input multi-output coupling system and has many inner nonlinear coupling characteristics,was deduced.For testifying the model,the levitation mechanism was firstly controlled by proportional-integral-differential(PID) control,and then a lot of input-output data were collected for model parameter identification.The least-square parameter identification method was used.The identification results prove that the model is feasible and suitable for the real system.
文摘High speed maglev train has become a new non-contact transportation mode mainly studied in recent years because of its non-sticking and high speed characteristics.Firstly,the finite element model of the long stator linear synchronous motor(LSM)is established based on the structure of the test prototype.After calculation,it is compared with the experimental data and verified.On this basis,a field-circuit coupling model based on inverter circuit is established,and the influence of carrier wave ratio change on the output characteristics of LSM is calculated and analyzed.Finally,the filter circuit is introduced into the field-circuit coupling model,and the influence of the filter circuit on the output characteristics of the LSM is compared and analyzed.
基金supported by the Science and Technology Research and Development Program of China State Railway Group Co.Ltd. (K2021X010).
文摘Purpose-This paper aims to provide top-level design and basic platform for intelligent application in China high-speed railway.Design/methodology/approach-Based on the analysis for the future development trends of world railway,combined with the actual development needs in China high-speed railway,The definition and scientific connotation of intelligent high-speed railway(IHSR)are given at first,and then the system architecture of IHSR are outlined,including 1 basic platform,3 business sectors,10 business fields,and 18 innovative applications.At last,a basic platform with cloud edge integration for IHSR is designed.Findings-The rationality,feasibility and implementability of the system architecture of IHSR have been verified on and applied to the Beijing-Zhangjiakou high-speed railway,providing important support for the construction and operation of the world’s first IHSR.Originality/value-This paper systematically gives the definition and connotation of the IHSR and put forward the system architecture of IHSR for first time.It will play the most important role in the design,construction and operation of IHSR.
基金Under the auspices of the National Natural Science Foundation of China (No. 49871026) key Directional Project of Knowledge Inno
文摘In this paper, the roles of infrastructure development and transportation coordination for Northeast Asian economic cooperation are discussed. It would be necessary to establish an efficient transportation network as soon as possible. "Hub-and-Spoke"transportation system and China-Korean peninsula railway container transportation system might be more significant for regional economic cooperation.
基金provided by National Natural Science Foundation of China (No.50678152)Scientific Plan Fund of Shaanxi Province (No.2009K09-24)
文摘Evacuated tube transportation(ETT) will be one of the ultra-large-scale vacuum application areas.This paper lists some key vacuum technology issues in ETT:(1) how to construct ultra-large-scale vacuum chamber with lower cost and high reliability,(2) how to evacuate gas out of the ETT tube in short time,(3) how to release heat or reduce temperature in the vacuum tube,(4) how to avoid vacuum discharge,(5) how to make vehicles with airproof shells and life support system,and(6) how to detect leaks and find leak positions efficiently.At the same time,some solutions are proposed.
基金support from the PCSIRT of the Ministry of Education of China(IRT0751)the National Natural Science Foundation of China (Grant Nos. 50588201, and 50872116)+3 种基金the National High Technology Research and Development Program of China (863 program: 2007AA03Z203)the Research Fund for the Doctoral Program of Higher Education of China (SRFDP200806130023)the Fundamental Research Funds for the Central Universities(SWJTU09BR152 and SWJTU09ZT24)the Doctoral Innovation Foundation of Southwest Jiaotong University (X1899124710003)
文摘The super-high speed high temperature superconductor (HTS) maglev evacuated tube transport (ETT) is a promising transport mode for the future. As a key component of the HTS maglev vehicle, the permanent magnet guide-ways (PMGs) with different geometrical configurations and iron yoke widths are analyzed by finite element method (FEM). The levitation force of a single onboard HTS maglev device over the designed PMG at different field cooling heights (FCH) is measured by magnetic levitation measurement system. Based on the designed PMG and experimental results, a preliminary scheme of subterranean super-high speed HTS maglev ETT is described in this paper. The HTS maglev ETT is mainly composed of an evacuated tube, HTS maglev vehicle, PMG, propulsion system, station, emergency rescue system, etc. In addition, a subterranean tube that consists of foundation tube and vacuum airproof layer is introduced. In order to convert the stress caused by the air pressure difference between inside and outside of the vehicle, a multi-circular vehicle body is designed. The vehicle is driven by a linear motor propulsion system under the control of a ground controlling system. The scheme of long-distance super-high speed passenger transportation is accomplished by the connection of different vehicles.
基金CRRC Sifang received partial funding for this project from the National Natural Science Foundation of China under Grant Number 52232013.This support is highly appreciated.
文摘High-speed Maglev is a cutting-edge technology brought back into the focus of research by plans of the Chinese government for the development of a new 600 km/h Maglev train.A Chinese‐German cooperation with industrial and academic partners has been established to pursue this ambitious goal and bring together experts from multiple disciplines.This contribution presents the joint work and achievements of CRRC Qingdao Sifang,thyssenkrupp Transrapid,CDFEB,and the ITM of the University of Stuttgart,regarding research and development in the field of high‐speed Maglev systems.Furthermore,an overview is given of the historical development of the Transrapid in Germany,the associated development of dynamical simulation models,and recent developments regarding high-speed Maglev trains in China.
基金supported by the National Natural Science Foundation of China(Nos.52272374 and 52072269)the Shanghai Soft Science Research Project(No.22692194800)the Fundamental Research Funds for the Central Universities,China.
文摘High-speed maglev trains will play an important role in the high-speed transportation system in the near future.However,under the conditions of strong magnetic fields and continuous operation,the actuators of the high-speed maglev train suspension system are prone to lose partial effectiveness,which makes the suspension control problem challenging.In addition,most existing fault-tolerant control(FTC)methods for suspension systems require linearization around the equilibrium points during the controller design or stability analysis.Therefore,from a practical perspective,this study presents a novel nonlinear FTC strategy with adaptive compensation for high-speed maglev train suspension systems.First,a nonlinear dynamic model of the suspension system based on join-structure is established and the actuator failures are described.Then,a nonlinear fault-tolerant suspension control law with an adaptive update law is designed to achieve stable suspension against partial actuator failure.The Lyapunov theory and extended Barbalat lemma are utilized to rigorously prove the closed-loop asymptotic stability even if there is partial actuator failure,without any approximation to the original nonlinear dynamics.Finally,hardware experimental results are included to demonstrate the effectiveness of the proposed approach.
基金Major Program of National Natural Science Foundation of China,No.41590840,No.41590842.
文摘Land-use efficiency is low for the urban agglomeration of China.High-speed transportation construction has been an important factor driving land use change.It is criti?cally importa nt to explore the spatial relati on ship between the high-speed transportation su?periority degree and land-use efficie ncy.We built a model to evaluate the ben efits of con?venient high-speed transportation using the relative density of highways and the distanee from high-speed rail stations and airports as a metric.We used 42 coun ties of the Shan dong Peninsula urban agglomeration as an example.Land?use efficiency was calculated by a DEA model with capital,labor,economic ben efits and envir on mental ben efits as input and output factors.We examined the spatial relati on ships betwee n high-speed tran sport superiority degree and land-use efficiency and obtained the following results.First,there are significant spatial differe nces in the relati on ships betwee n the high-speed transportati on superiority degree and land-use efficiency.Taking the two major cities of Jinan and Qingdao as the hubs,the core surrounding counties show significant spatial relationship between land-use efficiency and the high-speed transportation superiority degree.Spatial correlation declines as the distance from the hubs in creases.Land-use efficiency is less tha n high-speed tran sportation convenience in areas along the transportation trunks that are distant from the hub cities.Correlation is low in areas that are away from both hub cities and transportation trunk routes.Second,high-speed transportation has a positive relationship with land?use efficiency due to the mechanism of element agglomeration exogenous growth.Third,high-speed transportation facilitates the flow of goods,services and tech no logies between core cities and peripheral cities as space spillover(the hub effect).This alters the spatial pattern of regional land-use efficiency.Fin ally,the short-board effect caused by decreased high-speed tran sport corn struction can be balaneed by highway construction and the proper node layouts of high-speed rail stations and airports,resulting in a well-balaneed spatial pattern of land?use efficiency.
文摘At present, most of China's railway hubs are developed to be transportation complexes, with some problems like unsmooth traffic circulation, mixed but disordered functions, separated spaces, etc. In high-speed rail era, high-speed railway hubs should be regarded as the catalyst to promoted urban development. The mode of urban complex should be developed, to closely connect the railway hub and the surrounding area within walking distance, so as people could get to their destinations in the most convenient way. Furthermore, it would strengthen people's aggregation, thus to bring about larger scale urban development by the successful development of urban complex.
基金Project (No. 2005AA505440) supported by the Hi-Tech Researchand Development Program (863) of China
文摘The dynamic interaction between maglev vehicle and three-span continuous guideway is discussed. With the consideration of control system, the dynamic interaction model has been developed. Numerical simulation has been performed to study dynamic characteristics of the guideway. The results show that bending rigidity, vehicle speed, span ratio and primary frequency all have important influences on the dynamic characteristics of the guideway and there is no distinct trend towards resonance vibration when f1/(v/l) equals 1.0. The definite way is to control impact coefficient and acceleration of the guideway. The conclusions can serve the design of high-speed maglev three-span continuous guideway.
基金The National High Technology Research and Development Program(863)of China(No.863CF-G0403-01)
文摘The dynamic interaction between moving vehicles and two-span continuous guideway was discussed. With the consideration of the magnetic levitation system,the maglev vehicle/guideway dynamic interaction model was developed.Numerical simulation was performed to understand dynamic characteristics of the guide- way used in practice.The results show that vehicle speed,span length and primary frequency of the guideway have an important influence on the dynamic responses of the guideway and there is no distinct trend towards resonance vibration when f_1 equals 1.0.The definite way is to control the impact coefficient and acceleration of the guideway.The conclusions can serve the design of high speed maglev guideway.