交通运输工程学报

Research progress on wheel/rail rolling contact fatigue of rail transit in China

ZHAO Xin, WEN Ze-feng, WANG Heng-yu, TAO Gong-quan, JIN Xue-song

Abstract: The wheel/rail rolling contact fatigue was systematically explained in terms of its classification, initiation mechanisms, influencing factors, consequences, as well as commonly used initiation prediction models, and the source of complexity in wheel/rail rolling contact fatigue was summarized. Related research results of wheel/rail rolling contact fatigue in China Rail Transit System in recent years were summarized. The basic characteristics, initiation mechanisms as well as countermeasures in high-speed railway, traditional railway, and metro systems were summarized, respectively. The systematic use of research approaches such as the field monitoring, failure analysis of field samples, test rig, numerical simulation, and on-line test for studying local and continuous wheel/rail rolling contact fatigue were described, together with their important results. Root causes for differences between different rail transit systems in terms of wheel/rail rolling contact fatigue and the relative importances of these factors were discussed. Finally, suggestions were provided for future studies on practical countermeasures and initiation mechanisms. Research result shows that the wheel/rail local rolling contact fatigue (crescent crack) in high-speed EMU poses controllable threats to the operation safety, and is most often caused by indentations. Excessive contact stress and creepage are critical factors causing the continuous wheel/rail rolling contact fatigue, its root causes include the sharp curve, wheel/rail profile deterioration, inappropriate designs of contact profile and track curve, steep and undulating slope, low adhesion and adhesion enhancement, frequent start and stop, and track mounting error. The severe rolling contact fatigue observed on wheels of high-power electric locomotives widely used in recent decade operating in complex conditions, is the joint manifestation of the comprehensive effect of these factors. Feasible countermeasures for the rolling contact fatigue include the prevention or timely repair of severe indentations, improving wheel and rail profile compatibility in curved sections, optimizing wheel turning and rail grinding strategies, installing or improving the wheel tread cleaner, rolling stocks turn-around operating periodically, improving the electric compensation and traction/braking control in locomotives, using high quality sands for adhesion enhancement, improving the tread braking, and timely repair of key components on tracks and trains. The appropriate countermeasures may be selected according to the characteristics of each wheel-rail system. Relating to the field countermeasure, accurate rolling contact fatigue prediction models should be developed to facilitate rolling contact fatigue infinite- and finite-life designs and the determination of optimal wheel-rail maintenance strategies for different running conditions. Relating to damage mechanisms, future studies should be focused on the microcrack propagation mechanism and the influencing mechanism of wear during the fatigue-crack initiation stage. 1 tab, 42 figs, 150 refs.More>

2021, 21(1): 1-35. doi: 10.19818/j.cnki.1671-1637.2021.01.001

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Review on domestic and foreign dynamics evaluation criteria of high-speed train

SHI Huai-long, LUO Ren, ZENG Jing

Abstract: The evaluation content, evaluation method, evaluation index and limit value involved in the dynamics performance assessment criteria were reviewed for high-speed trains. The criteria analysis and their comparisons were carried out regarding of hunting motion stability, derailment safety and ride quality, including legal documents, industry standards and technical specifications, for instance, ISO series, UIC series, EN series, TSI series, FRA series, APTA series and GB series standards, etc. Deficiencies or suggestions for improvement were pointed out. Detailed comparison among representative dynamics criteria were carried out, including new and old versions of the national standard Specification for Dynamic Performance Assessment and Testing Verification of Rolling Stock (GB/T 5599), the International Railway Union Testing and Approval of Railway Vehicles from the Point of View of Their Dynamic Behaviour—Safety—Track Fatigue—Ride Quality (UIC 518), and the Russian Railway Multiple Units—Durability and Dynamics Requirements (GOST/R 55495), etc. Applications of the dynamic response and quasi-static performance evaluation criteria under ideal track excitations specified by the North American FRA series and APTA series were demonstrated. Analysis result shows that the hunting motion stability is evaluated by the lateral acceleration of frame, frame force or the wheel/rail force, while the suitable method should be selected for the numerical simulation, bench test and on-track test. Regarding the long-term service dynamics performance of high-speed trains in China, it is recommended to set the frequency bandwidth of filtering as 0.5-10.0 Hz, the amplitude limit as 8 m·s^-2 below 7 Hz and 10 m·s^-2 for 7-9 Hz, the continuous over-limit times as 10 times, 2 s or 100 m in case of the high-speed trains are operated at 400 km·h^-1 and above. For the safety assessment of rail climbing derailment, the existing standards are based on the wheel/rail force and wheel lift for dynamic and static evaluations, but there are differences in the index limit, time duration or running distance of action. It is recommended to use the derailment coefficient and wheel unloading coefficient to form a joint evaluation method. The new version of GB/T 5599 deletes the overturning coefficient and wheel/rail lateral force indicators, relaxes the limit of wheel unloading coefficient, and remains the wheel/axle lateral force limit unchanged. The evaluation method of GOST/R 55495 does not distinguish the vehicle types, and uses the frame force instead of wheel/rail force to evaluate the operational safety. A same frequency weighting is used for the calculation of lateral and vertical ride quality index, and the weighting bandwidth as well as the amplitude of low frequency band are significantly larger than that of GB/T 5599. GOST/R 55495 does not grade the ride quality index. The operational safety index and ride quality index of CR400BF Fuxing high-speed train both meet the requirements of GB/T 5599 and GOST/R 55495. The North American criterion was employed to analyze the dynamic response of a 160 km·h^-1 passenger car under ideal track excitations. Among the eight types of irregularities, the repeated surface irregularities and single surface irregularities are relatively harsh. Among the six evaluation indicators, the wheel unloading coefficient and the vertical acceleration of car body easily exceed the limits. 9 tabs, 22 figs, 67 refs.More>

2021, 21(1): 36-58. doi: 10.19818/j.cnki.1671-1637.2021.01.002

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Review on aerodynamic drag reduction optimization of high-speed trains in China

LI Tian, DAI Zhi-yuan, LIU Jia-li, WU Na, ZHANG Wei-hua

Abstract: The progress on aerodynamic drag reduction optimization of high-speed trains in China was studied. The pressure distribution characteristics of typical components and the contribution of each component to the train's aerodynamic drag were summarized. Three research methods for obtaining train aerodynamic drag, including full-scale experiments, wind tunnel tests, and numerical simulations, were evaluated. The differences in aerodynamic performances of train heads of Hexie and Fuxing were discussed. The optimization methods and technologies of aerodynamic drag reduction for high-speed train heads were expounded. The aerodynamic drag reduction measures of bogies, inter-car connections, pantographs, and deflectors were analyzed, and the potential technologies suitable for high-speed train drag reduction were summarized. Analysis results show that there are both advantages and disadvantages of numerical simulation and wind tunnel test, the numerical simulation as validated by the wind tunnel test is an effective means of accurately calculating the aerodynamic drag of the train. The main components contributing to the aerodynamic drag of the train are leading car, trailing car, bogie, pantograph, and inter-car connection. As existing high-speed trains are highly streamlined, achieving further drag reduction by optimizing the head shape is difficult. Optimizing the skirts of the bogie area, incorporating an all-inclusive outer windshield, and optimizing the pantograph and deflector shape are effective measures for further reducing drag. The optimization of multiple objectives including drag and noise reduction and improvements to operational stability and riding comfort are the developmental trends of train head shape design. Through direct optimization calculation or surrogate model optimization calculation, the optimization efficiency can be improved, and the optimization cost can be reduced. In the future, bionic surface microstructure, blowing and suction flow control, plasma drag reduction, and vortex generator technologies should be further studied to achieve green, energy-saving, and rapid development of high-speed trains in China. 1 tab, 20 figs, 109 refs.More>

2021, 21(1): 59-80. doi: 10.19818/j.cnki.1671-1637.2021.01.003

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Progress and challenge on fatigue resistance assessment of railway vehicle components

WU Sheng-chuan, REN Xin-yan, KANG Guo-zheng, MA Li-jun, ZHANG Xiao-jun, QIAN Kun-cai, TENG Wan-xiu

Abstract: Based on the safety operation and service assessment of vehicle components, the progress on fatigue resistance assessment and engineering application of railway vehicle components mainly including the axles and bogie frame was reviewed. The different design concepts due to axle materials as well as the limitations of difficult quantitative and over-conservative theoretical approaches to the safety assessment of axles (EA4T and S38C) were analyzed. The stepwise fatigue assessment approach to incorporate the nominal stress and damage tolerance was first developed with four key technologies of the improved principle of sample-polymerization, uniaxial tensile based crack growth model, stress-defect-lifetime assessment diagram and reconstruction of surface residual stress. Analysis result shows that the traditional nominal stress based fatigue resistance design leads to conservative lifetime prediction, insufficient or frequent inspection. The accuracy of the novel uniaxial tensile based crack growth model is superior to the NASGRO equation. The Kitagawa-Takahashi diagram combines the nominal stress based fatigue limit with the fracture mechanics based defect geometry, which is more intuitive, quantitative, and comprehensive than the Goodman diagram. The compressive residual stresses of S38C axles are rebuilt by using a unit pressure approach, which is in good agreement with the experimental results. The introduction of compressive residual stresses leads to an improvement in the fretting and fatigue crack growth resistance of Shinkansen axles. Important project are listed including the wide domain environment service, ultra-high cycle fatigue, additive repair and remanufacturing, fracture solution technique, and the combination of dynamics and strength. 45 figs, 201 refs.More>

2021, 21(1): 81-114. doi: 10.19818/j.cnki.1671-1637.2021.01.004

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Review on frontier technical issues of intelligent railways under Industry 4.0

MIAO Bing-rong, ZHANG Wei-hua, LIU Jian-xin, ZHOU Ning, MEI Gui-ming, ZHANG Ying

Abstract: The importance and necessity of the rational use of the connotative elements of Industry 4.0 for the digital construction, transformation, and upgrading of the next generation intelligent railways of China were explained. To this end, railway infrastructures and vehicles were considered as research objects, and frontier technologies and methods pertaining to intelligent manufacturing were combined. Based on the impacts of basic concept, technical connotation, system model, and technical framework of Industry 4.0, the implementation processes and existing problems of intelligent infrastructure, smart train, intelligent operation and maintenance, and related technologies were compared and analyzed. In addition, the key technologies for the digital platform construction of intelligent railways focusing on smart trains were analyzed. The specific technical requirements for the digital construction corresponding to traditional manufacturing to intelligent manufacturing were summarized. Problems pertaining to the integration of frontier technologies, such as artificial intelligence, big data, cloud computing, and digital twins, with the traditional railway manufacturing, were compiled and solved using a six-dimensional model of Industry 4.0. These problems included the data transmission and sharing, exploration of the potential of information communication and security technology, and intelligent management, technology application, information security, and intelligent state awareness. Research result demonstrates that the integration of digital information technology and intelligent technology with the traditional manufacturing process is insufficient. The core know-how of intelligent manufacturing is inadequate. A lack of autonomy of software and hardware technologies, such as intelligent state awareness, online data analysis, and industrial control systems, is observed. The data transmission and standard system for the construction of big data for the railway system is not perfect. The digital design, upgrade, and transformation of the standardized management system and data information security system of railway traditional manufacturing in Industry 4.0 should be strengthened in future intelligent railways. Deep thinking and analysis of the integration and implementation of frontier technologies including artificial intelligence and big data drive in railways are required. Various key technologies covered in Industry 4.0 should be implemented and accurately evaluated to truly and effectively promote the construction and development of an advanced digital platform for intelligent railways of China. 1 tab, 13 figs, 69 refs.More>

2021, 21(1): 115-131. doi: 10.19818/j.cnki.1671-1637.2021.01.005

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Development of additive manufacturing technology and its application prospect in advanced rail transit equipment

YANG Bing, LIAO Zhen, WU Sheng-chuan, XIAO Shou-ne, YANG Guang-wu, ZHU Tao, WANG Ming-meng, DENG Yong-quan

Abstract: Based on the application status of additive manufacturing technology, the characteristics and application ranges of several additive manufacturing technologies were summarized. The latest research progress of typical metal additive manufacturing was introduced. Considering the inherent defects, residual stresses and cracks of the existing additive manufactured parts, the post processes which can effectively improve the quality of the formed additive manufactured parts were summarized. The influencing factors of fatigue performance of additive manufactured parts were sorted out, and the correlation between defect and fatigue damage of additive manufactured parts was emphasized. The key technologies involved in the wide application of additive manufacturing technology were discussed. The application status of metal additive manufacturing technology in the field of rail transit equipment at home and abroad was systematically summarized. Analysis result shows that the texture characteristic and mechanical properties of materials prepared by the additive manufacturing technology are different due to different heat sources and process parameters. Additive manufacturing titanium alloy, aluminum alloy and other advanced metal materials have a good application prospect in the field of rail transit equipment. Reasonable post processes can effectively control the formation of defects, eliminate residual stresses and reduce micro cracks. Defects are the key factors to restrict the application of additive manufacturing technology in the manufacturing industry, it is important to study the distribution law of defects and explore the relationship between defects and fatigue performance for the evaluation of fatigue performance of additive manufactured parts. From the aspects of material specification, forming accuracy, quality control, production efficiency, production chain and nondestructive testing technology, comprehensively improving the independent and innovative research and development of key technologies of additive manufacturing is conducive to enhancing the competitiveness of Chinese manufacturing industry in the world. The additive manufacturing technology has attracted the attention of rail transit industry, and begin to adopt this new technology to form metal structural parts, but the wide application of this technology still faces many problems, which need to carry out in-depth research by the scholars at home and abroad. 2 tabs, 21 figs, 111 refs.More>

2021, 21(1): 132-153. doi: 10.19818/j.cnki.1671-1637.2021.01.006

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Application and prospect of composite materials in rail transit vehicles

XIAO Shou-ne, JIANG Lan-xin, JIANG Wei, HE Zi-kun, YANG Guang-wu, YANG Bing, ZHU Tao, WANG Ming-meng

Abstract: The use of composite materials such as the glass fiber reinforced plastic, carbon fiber reinforced plastic, and aluminum matrix ceramic composite materials in rail transit vehicles was reviewed. The history and progress of basic and applied research on the aforementioned composite materials were described, and the structural characteristics of these materials when used in large composite components were analyzed. A systematic summary was provided on the types, forming processes, design methodologies, and optimization of composite materials used in the lead car/cab, the carbody of middle cars, bogie, brakes, and other structures, the application of composite materials in all the components of a rail transit vehicle was comprehensively described. Current problems and future trends of composite material usage in rail vehicles were also described. Analysis result shows that the studies regarding composite materials are primarily based on theoretical approaches, and finite element analysis is usually used in large structural components. Multi-scalar methods are used in detailed analyses to study how composite materials behave at the microscopic, mesoscopic, and macroscopic levels. When composite materials are applied to structures, the sandwich structure is mostly used in considering the stiffness and lightweight. As the connection structure between composite materials, composite materials and metal materials, the adhesive connection, bolt connection, adhesive-bolt mixed connection are mostly used. The mixed connection structure has higher strength and stability, which is most widely used in engineering. Composite materials have been used in rail transit vehicles, including the fiber reinforced composite materials used in lead car/cab, carbody, bogie, and the aluminum matrix ceramic composite materials used in brake structure. In the future, relevant standards and specifications applicable to rail transit industry should be established, new technologies should be developed, and overall design mode should be adopted. The using range of composite materials should be expanded, and higher performance, lower cost and lighter composite materials should be applied to rail transit vehicles. 2 tabs, 14 figs, 167 refs.More>

2021, 21(1): 154-176. doi: 10.19818/j.cnki.1671-1637.2021.01.007

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Research progress of high-speed maglev rail transit

XIONG Jia-yang, DENG Zi-gang

Abstract: The development of high-speed maglev rail transit across the world was summarized based on the basic operating principles and technical characteristics of maglev trains. The electromagnetic suspension (EMS), permanent magnet electrodynamic suspension (PMEDS), low-temperature superconductor electrodynamic suspension (LTSEDS), and high-temperature superconducting magnetic levitation (HTS maglev) were compared in terms of their research histories, suspension characteristics, suspension gaps, suspension energy-consumption levels, control systems, technical maturity, and state of use. The progress of research on high-speed maglev in domestic and foreign universities, research institutions, and enterprises was summarized based on the literature research, comparison, analysis and refinement. The principles, technical strengths and weaknesses of various maglev rail transits were compared to analyze the viability and inadequacies of high-speed maglev rail transit in practical applications. The technical economy, application prospects and scenarios of four maglev modes were discussed. Six key scientific problems for the development of high-speed and ultra-high-speed vacuum-tube maglev rail transit were identified. These include the traction/braking control, kinetics and thermodynamics, safety and rescue protocol, sealing performance and vacuum pumping efficiency of tube, wireless communication, and interior environment control. The progress and plan of research and development in basic research and key technologies for HTS maglev originated in China were also described. Research results shows that the EMS or superconducting maglev technology is suitable for speeds between 400 km·h^-1 and 600 km·h^-1. The superconducting maglev technology can be used for speeds between 600 km·h^-1 and 1 000 km·h^-1. Speeds of 1 000 km·h^-1 or greater require the maglev technologies of HTS maglev or EDS with vacuum-tube. As a prospective study, the technological breakthrough and validation in HTS with vacuum-tube maglev have profound and far-reaching implications on the rapid development of rail transit in China and even the world. 2 tabs, 15 figs, 72 refs.More>

2021, 21(1): 177-198. doi: 10.19818/j.cnki.1671-1637.2021.01.008

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Research review on medium and low speed maglev vehicle

MA Wei-hua, LUO Shi-hui, ZHANG Min, SHENG Zhuo-hang

Abstract: Based on the working principle of electro-magnetic suspension (EMS) type medium and low speed maglev (MLSM) train, the technical characteristics of each core subsystem (levitation-guidance system, traction motor, running gear, braking system and track-bridge structure, etc.) of MLSM train were described, and the technical problems and solutions of each subsystem were comprehensively analyzed. The development histories and technical characteristics of Linimo train in Japan, EcoBee train in Korea, maglev express in Changsha, maglev line S1 in Beijing as well as the self-developed MLSM train with mid-set suspension of Southwest Jiaotong University were summarized, and also the technical key points and difficulties of MLSM train. Research results show that, for the vehicle-guideway coupling vibration, a complete vehicle-guideway coupling vibration research model should be established considering the influences of levitation control, structural parameters of vehicle and bridge, aerodynamic effect, linear induction motor and other factors. For the lack of suspension redundancy, the redundancy design scheme of MLSM should be improved by comprehensively utilizing the characteristics of mechanical redundancy and electrical redundancy. For the boots-rail current collection, the current collection relationship of maglev boots-rail should be distinguished from metro boots-rail, the coupling characteristics of maglev train are fully considered, and the engineering practicability of seamless power rail technology in MLSM is explored. For the levitation control, the accuracy and stability of control algorithm and levitation system fault diagnosis technology should be improved due to the low dominant frequency of controller and long running cycle of program. For the light-weight design of vehicle, the structural characteristics of vehicle, running gear and other factors should be comprehensively considered on the basis of ensuring the structural strength, so as to improve the MLSM train carrying capacity. In addition, a unified track standard should be established based on different maglev line requirements, so as to improve the engineering application ability of MLSM. 7 tabs, 12 figs, 97 refs.More>

2021, 21(1): 199-216. doi: 10.19818/j.cnki.1671-1637.2021.01.009

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Review on permanent magnet direct drive technology of railway vehicles

MA Guang-tong, SUN Zhen-yao, XU Shuai, YAO Chun-xing, REN Guan-zhou, LIANG Shu-lin

Abstract: The development of domestic and overseas railway vehicles adopting permanent magnet direct drive technology was reviewed. The forms of permanent magnet direct drive bogies structures were summarized, and the characteristics and applications of the shaft-holding direct drive structure and elastic suspension direct drive structure were discussed. The snaking operation stability and curve passing ability of permanent magnet direct drive bogies were analyzed. According to railway vehicle application conditions, the structure design and optimization methods of permanent magnet direct drive motors were discussed in terms of magnetic materials, cooling system, temperature rising effects, motor mass, air gap flux density, back electromotive force suppression, demagnetization faults, and circuit structure. Conventional control strategies for traction motors were analyzed. The current research status of model predictive control and sensorless control technologies were discussed, and moreover, their feasibility and application challenges for permanent magnet direct drive motors were studied. Existing challenges associated with permanent magnet direct drive technology for railway vehicles and outlook for future development were summarized. Research results suggest that the shaft-holding direct drive structure is compact but only suits for low-speed trains, since the motor is greatly affected by wheel-rail vibration and will increase the unsprung mass. The elastic suspension direct drive structure can be suitable for high-speed trains, however, further studies should be investigated on the elastic connection mechanisms between the permanent magnet motor and direct drive bogie, the optimal matching parameters, and the optimal suspended and unsprung mass distributions. The permanent magnet direct drive inboard bearing bogie can shorten the axle length and wheelbase, which is suitable for complex terrains application due to its advantages of low mass and good dynamic properties. The faster and more accurate online diagnosis and warning methods with the fault suppression strategy for the permanent magnet direct drive motors need to be studied, which can adopt the fault diagnosis and prediction strategy based intelligent operation and maintenance technique, so as to give a guidance for the vehicle maintenance. There is also a need for further optimization on the topologies of stator and rotor of permanent magnet direct drive motors, where a more effective cooling structure and an accurate calculation method for the temperature increase should be put forward. Traditional field oriented control and direct torque control have difficulties in achieving the high-torque dynamic response and low-torque ripple simultaneously, while model predictive control is more suitable for high power applications with low switching frequency such as railway vehicles due to their advantages of simple structure and fast dynamic response. However, further studies need to be focused on the reduction of the computational burden and the improvement of steady-state performance. Sensorless control technology saves the internal space of motor and avoids some reliability problems due to the elimination of encoders, which is suitable for direct drive bogies with small internal spaces. The state of art sensorless technology has good performance in medium to high speed ranges. The high-frequency signal injection strategies for zero to low speed can realize the accurate position estimation, but further investigations are needed to eliminate its adverse effects to motor control performance.19 figs, 89 refs.More>

2021, 21(1): 217-232. doi: 10.19818/j.cnki.1671-1637.2021.01.010

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Review on influence of coupler and draft gear on safety of railway train collision

ZHU Tao, ZHANG Jing-ke, WU Qi-fan, LYU Rui-juan, WANG Xiao-rui, XIAO Shou-ne, DENG Yong-quan

Abstract: The research methodologies and results of coupler and draft gear in the field of train collisions in last 20 years were reviewed from four specific aspects of coupler and draft gears in train: function and failure mechanisms, classifications and standards, theories and applications, and train collision responses. The strengths, weaknesses, and future problems to be solved of these four studies were summarized. The role of coupler and draft gear in train collisions, as well as its position in the overall design of vehicle system, was discussed from the perspective of kinematic theory of train collisions. The compositions of sub-components of coupler and draft gear were introduced based on the crashworthiness and strength standards of trains in European Union, the United States, Japan, and China.The evolution of the theoretical model of coupler and draft gear was analyzed from its application in train collision dynamics model and finite element model.Research trends and development goals of coupler and draft gear were described based on the current state of coupler and draft gear worldwide. Research results show that coupler and draft gear is one of the important components in the multistage energy-absorption systems of trains. It is necessary to establish different mechanical models for different types of coupler and draft gears to accurately reflect the nonlinear hysteresis characteristics of the buffer, the energy absorption characteristics of the collapse pipe, and the dynamic characteristics of coupler and draft gear during collision. The coupler draft gear standards that currently exist in China and abroad only specify the static strength indices for coupler draft gears and only provide detailed specifications for freight-car coupler draft gears. The standardized load indicators and energy limits for the coupler and draft gear are scarce of high-speed trains in dynamic scenarios. Although elastomer and gas-liquid buffers have better mechanical collision properties than friction buffers, their complex nonlinear characteristics depend on accurate mathematical models and tests. At present, the transverse and vertical dynamic characteristics of the mathematical model of coupler and draft are yet to be formulated in details.Tests should be used to strengthen studies on the activation and failure stability of coupler and draft gears in train-operation and train-collision processes, as well as their effects on the longitudinal collision response of train cars.High stiffness levels in coupler and draft gear can lead to abnormal vertical and horizontal responses at low and medium speeds.The mechanical properties and initial attitudes of coupler and draft gears at different speed levels have great influence on vehicle collision mechanism. 2 tabs, 17 figs, 91 refs.More>

2021, 21(1): 233-249. doi: 10.19818/j.cnki.1671-1637.2021.01.011

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Application advances of artificial intelligence algorithms in dynamics simulation of railway vehicle

TANG Zhao, DONG Shao-di, LUO Ren, JIANG Tao, DENG Rui, ZHANG Jian-jun

Abstract: The application examples and domestic and foreign literatures using artificial intelligence algorithm for railway vehicle system dynamics simulation were reviewed. The machine learning and deep learning algorithms commonly used in railway vehicle dynamics simulation were summarized, and the application classifications of the 2 algorithms in railway vehicle system dynamics modelling and simulation were concluded and interpreted. According to railway vehicle system dynamics modelling, dynamics performance prediction and dynamics performance optimization, the advantages and limitations of applying artificial intelligence algorithms in force-elements modelling and simulation, track irregularity prediction, running stability prediction, noise prediction, crosswind safety prediction, running safety prediction, suspension optimization, wheel-rail matching optimization, structure optimization, and active and semi-active control were discussed in detail. The problems of applications of artificial intelligence algorithms in railway dynamics simulation were lack of training samples, generalization ability and interpretability. The development directions and key research contents of the interdisciplinary research between artificial intelligence and vehicle system dynamics were given. Research result shows that the hybrid modelling theory combining classical mechanics and artificial intelligence algorithms can be as a key research direction in the future. There is great potential to use the artificial intelligence algorithms to solve the random uncertainty in stochastic dynamics and improve the performance of stochastic dynamics. The artificial intelligence algorithms combinated with optimization algorithms can exploit their advantages in the dynamics performance optimization. 5 tabs, 12 figs, 77 refs.More>

2021, 21(1): 250-266. doi: 10.19818/j.cnki.1671-1637.2021.01.012

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Review on active control of hunting stability for railway vehicles

HUANG Cai-hong, ZENG Jing, WEI Lai

Abstract: In order to suppress the hunting motions and thus increase the critical speed of vehicles, the structure concepts, control objectives, control algorithms, measurement systems, actuation systems and experimental verifications were reviewed on the active control of hunting stability for the special self-excited vibration system of railway vehicles. The typical structural concepts and their characteristics were summarized. The main objectives of active stability control were concluded according to the different application scenarios, and the algorithms of stability control were also summarized, including their advantages and disadvantages. The feasibility and reliability of different feedback measurement methods were analyzed, and the influence of actuator dynamic characteristics on the control effect was commented. The experimental methods of active stability control were given, and the future research focus of active stability control were prospected with respect to algorithm design, failure safety, and some other aspects. Analysis results show that in the active control of hunting stability, the selection of control concept and algorithm should consider the different control objectives. In addition to the active control of secondary hunting stability under high wheel-rail combination conicity, the active control of primary hunting stability under low wheel-rail combination conicity should also be considered. The structure concept should be simple, reliable and easy to be implemented, and has a low requirement for the measurement system. The measurement system should be simple and measurable as far as possible to reduce the influence of random disturbance and noise on the reliability of measurement results. The practical effectiveness of active control of hunting stability is determined by the response time of actuator and the compensation method of time delay. The control system can not affect the safety of train operation after its failure, which is the most crucial aspect to decide the application of active control. 14 figs, 87 refs.More>

2021, 21(1): 267-284. doi: 10.19818/j.cnki.1671-1637.2021.01.013

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Review on wheel-rail dynamic responses caused by wheel tread defects

JING Lin, LIU Kai

Abstract: The current research on wheel-rail relationship was summarized in three aspects, including rolling contact theories, experiments, and numerical simulations. The influence of dynamics mechanical properties of wheel/rail materials on wheel-rail rolling contact behavior was emphasized. The related results on the static and dynamic mechanical properties of wheel/rail materials and constitutive relationship were summarized. A systematical introduction was presented on the progress of research on wheel-rail dynamic responses caused by wheel flat, tread spalling, wheel polygonization, and other typical tread influences, mainly including the influence of wheel tread defects on wheel-rail rolling contact behavior and vehicle system dynamics, and the causation, influence rules and evolution mechanism of wheel tread defect. The influences of dynamic effects on high-speed wheel-rail rolling contact behavior was emphasized and the detection technologies and prevention measures of wheel tread defects were summarized. Analysis results suggest that the wheel tread defects significantly increase the wheel-rail impact force, resulting in damages of wheel-rail components and abnormal vibration of car body, which seriously affect the service life of vehicle-track components and vehicle dynamics performance, and even threaten the safety of train operation. The causes and mechanisms of wheel tread defects still need to be further explored, abnormal braking of vehicle and low adhesion state between wheel and rail will lead to wheel flat, characteristics of wheel/rail materials, wheel-rail contact load, wheelset resonance, performance of braking system and operation conditions/environment are the main factors leading to wheel tread spalling, wheel-axle resonance, wheel-rail friction vibration, wheel manufacturing and re-profiling are closely related to the formation of wheel polygonization. Improving the performance of wheel/rail materials, controlling the support stiffness/damping of track system and friction coefficients between wheel and rail are all effective measures to restrain wheel tread defects. 3 tabs, 19 figs, 209 refs.More>

2021, 21(1): 285-315. doi: 10.19818/j.cnki.1671-1637.2021.01.014

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Review on basic characteristics, formation mechanisms, and treatment measures of rail corrugation in metro systems

GUAN Qing-hua, ZHANG Bin, XIONG Jia-yang, LI Wei, WEN Ze-feng, WANG Heng-yu, JIN Xue-song

Abstract: The basic characteristics of rail corrugations in metro systems worldwide were systematically reviewed, including their typical properties such as universality, time concentration, and the correlation between the corrugations and curve parameters, track structure, vehicle characteristics, and other related factors. The classification methods, formation mechanisms, and treatment measures of rail corrugation in metro were comprehensively evaluated. Research results show that rail corrugation is common in metro and tram lines, particularly in the initial stage of new line opening and line reconstruction. Generally, the rail corrugation of small radius curve is more common than that of straight line and large radius curve, and the wavelength is relatively shorter and the amplitude is larger in low-rail side than that in high-rail side. However, there are still exceptions, that is, rail corrugations are also distributed on some large radius curves and straight lines.The wavelength and growth rate of corrugation are closely related to the track structure. Rail corrugation grows rapidly when the track structure and its components are not compatible. Vehicle structural parameters such as the wheel tread, wheelset alignment, suspension stiffness, and unsprung mass, will affect the generation, growth, and characteristics of rail corrugation. The rail material, traction and braking, operation environment, humidity, and friction coefficient may also influence the generation of rail corrugation. The formation mechanism of metro rail corrugation is mainly based on the resonance of wheel-rail system, stick-slip (friction-induced self-excitation) vibration of wheel-rail, and the reflection of rail vibration wave. The effects of longitudinal dynamics on the rail corrugation formation and nonlinear factors in the wheel-rail system are not thoroughly explored. The understanding about the effects of self-excited stick-slip vibration and negative friction characteristics on the corrugation are not unified. Therefore, it is difficult to explain the differences in corrugation characteristics among the low curve rail, high curve rail, and straight line rail. The prediction theory and experimental validation in the formation and growth of rail corrugation are not sufficient. Currently, rail grinding is widely adopted to control the development of corrugation in various countries worldwide. The research on active methods to control corrugation, such as adjusting track structure, operation condition, adopting rail vibration absorbers, applying wheel-rail friction modifiers, and optimizing vehicle design optimizations, are still need to develop further. According to the dynamic characteristics of vehicle-track system and the micro contact behavior and self-excited stick-slip vibration of wheel-rail in real operation conditions, the wheel-rail dynamic wear evolution simulation of vehicle-track system should be carried out, the formation mechanisms and the key factors influencing the laws of metro rail corrugation should be mastered, and the active measures to control metro rail corrugation and the optimal design principles of wheel-rail compatibility should be developed. 5 figs, 132 refs.More>

2021, 21(1): 316-337. doi: 10.19818/j.cnki.1671-1637.2021.01.015

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Review on structural vibration damage identification technology for railway vehicles

MIAO Bing-rong, LIU Jun-li, ZHANG Ying, YANG Shu-wang, PENG Qi-ming, LUO Yao-xiang

Abstract: The importance and necessity of using the structural vibration damage identification technology for monitoring the structural health of railway vehicles were described in the context of intelligent operation and maintenance. According to the application ranges of different damage identifications, the structural vibration damage identification technology was classified into the model-based and response signal-based methods. Different methods characterized by the existence, type, location, and severity of structural damage were analyzed based on different damage identification hierarchies in structural health monitoring. Typical characteristics of damage identification technology during the operation and maintenance of railway vehicles were briefly outlined. In addition, the strength and weakness of model-based damage identification with respect to its modal parameters such as the natural frequency, modal shape, and curvature mode shape were evaluated. The application states and development trends of response signal-based methods were analyzed, and the applications of model modification and optimization technology in the structural damage identification were also described. A detailed analysis was focused on the implementation of damage identification technology in the fault diagnosis and monitoring of vehicle key components, and the most prominent trend of structural vibration damage identification technology in the intelligent operation and maintenance of future railway vehicles was discussed. The state maintenance strategy and intelligent operation and maintenance technology for railway vehicle components were also prospected. Research result shows that the fusion of structural vibration damage identification technology with new methods, such as the artificial intelligence, should be thoroughly considered in the intelligent operation and maintenance of railway vehicles. The big data-driven structural vibration damage identification technology can better solve the technical difficulty in the real-time state monitoring of railway vehicles. It is necessary to further refine the structural vibration damage identification technology and method based on the coupled vibrational modes, owing to the effect of complex environmental factor on the damage identification technology for the railway vehicle structural components. 1 tab, 4 figs, 130 refs.More>

2021, 21(1): 338-357. doi: 10.19818/j.cnki.1671-1637.2021.01.016

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Review on key technologies of 400 km·h^-1 variable gauge EMUs bogies

HUANG Zhi-hui, HU Fei-fei, LI Guo-dong, ZHOU Dian-mai

Abstract: To address the problems in the development and design of 400 km·h^-1 variable gauge EMUs bogies in China, five important problems for Chinese high-speed variable gauge EMUs bogies (i.e., traction motor mounting, type of wheel set drive, axle box bearing, track changing mechanism, foundation brake, and sanding device) were studied based on the mature variable gauge bogie technologies developed in other countries. Corresponding solutions to the problems discovered in this study were also proposed. Research result shows that both the electric motor suspension and body suspension can make room for the installation of brake disc, but those will be relative displacements between the motor and the driven axles, which requires motion compensation measures. To meet the requirements of axle size and rotating speed of 400 km·h^-1 variable gauge EMUs, it is necessary to develop new axle box bearings. The existence of track changing mechanism will increase the unsprung mass of bogie, so the developed variable gauge bogie should adopt a lightweight design as much as possible. Considering the effects of braking efficiency and caliper follow-up on the braking effect of variable gauge bogie, the basic braking should be given priority to the axle disc braking, followed by the wheel disc braking. Sanding device shall not be used for bogie of EMU, if it is absolutely necessary, considering using a hose connection between the sandbox and the sandblasting nozzle to adapt to the motion compensation when the gauge changes. While researching and developing the variable gauge bogie, attention should be paid to the wide use of ground track changing device, so that they can also meet the requirements of simplicity and standardization. The development of variable gauge bogie must consider the clearance requirements of different gauge railways, the greater the gauge difference, the higher the clearance requirement. On the rolling vibration test-bed of Southwest Jiaotong University, the maximum running speed of the developed EMU reaches 602 km·h^-1 under the condition of applying line spectrum excitation of Chinese passenger dedicated line and it was successfully launched in October 21, 2020. 2 tabs, 10 figs, 36 refs.More>

2021, 21(1): 358-368. doi: 10.19818/j.cnki.1671-1637.2021.01.017

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