scholarly journals Key Factors of the Initiation and Development of Polygonal Wear in the Wheels of a High-Speed Train

2020 ◽  
Vol 10 (17) ◽  
pp. 5880
Author(s):  
Yue Wu ◽  
Xuesong Jin ◽  
Wubin Cai ◽  
Jian Han ◽  
Xinbiao Xiao
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Interaction Force ◽  
Key Factors ◽  
Resonant Frequencies ◽  
Operation Speed ◽  
High Speed Trains ◽  
Train Operation ◽  
Flexible Deformation ◽  
Polygonal Wear

The polygonal wear of train wheels occurs commonly in rail transport and increases the wheel–rail interaction force dramatically and has a bad effect on the safety and comfort of the train. The mechanism of polygonal wear needs to be studied. The characteristics of test data measured from 47,000 sets of polygonal wheels of high-speed trains were analysed statistically. The analysis shows that, in the entire use life cycle of the wheels, the order (wavelength) and development speed of polygonal wear are different; they correspond to different wheel diameters because of wear and re-profiling. A prediction model, which considered the flexibility of the wheelset for the polygonal wear of the wheels of high-speed trains, was developed to explain this phenomenon. This theoretical model analyses the initiation, development, and characteristics of polygonal wear. The analysis includes the effect of the high-frequency flexible deformation of the wheelset, train operation speed, and wheel diameter variation. This study suggests that, if the wheel perimeter is nearly an integral multiple of the wavelength of severe periodic wear along the wheel circumference, the polygonal wear on the wheel can develop quickly. Furthermore, the wavelength of the periodic wear of the wheel relies on the operation speed of the train and wheelset resonant frequency. Therefore, the initiation and development of polygonal wear on wheels depends on the operation speed, wheel diameter, and the resonant frequencies of the wheelset. This conclusion can be applied to research concerning measures associated with the suppression of polygonal wear development.

Influence of Wheel Polygonal Wear on Interior Noise of High-Speed Trains

2017 ◽  
pp. 373-401 ◽  
Author(s):  
Jie Zhang ◽  
Guang-xu Han ◽  
Xin-biao Xiao ◽  
Rui-qian Wang ◽  
Yue Zhao ◽  
...  
Keyword(s):  
High Speed ◽  
Interior Noise ◽  
High Speed Trains ◽  
Polygonal Wear

scholarly journals Determination of Necessary Subsidiary Track According to Train Operation Frequency in a Heterogeneous Train Pattern

2020 ◽  
Vol 10 (12) ◽  
pp. 4164
Author(s):  
Hyoung June Kim
Keyword(s):  
Genetic Algorithm ◽  
Waiting Time ◽  
High Speed ◽  
The Third ◽  
Railway Construction ◽  
Different Types ◽  
High Speed Trains ◽  
Train Operation ◽  
Operation Frequency

In this study, a genetic algorithm was used to calculate the scheduled waiting time according to the train operation frequency of heterogeneous trains operating on one track. The acquired data were then used to determine the appropriate subsidiary track at which high-speed trains can load or release cargo away from low-speed trains. A metaheuristic genetic algorithm was applied and implemented using Javascript/jQuery. Six cases were investigated, which provided values of subsidiary track that vary according to the operation frequencies of different types of trains, and solutions were derived through 100 simulations using a stochastic method. The analysis results showed that the train overtaking frequency was the highest at the third intermediate station within the simulation, suggesting that this particular station requires a subsidiary track, even if the operating frequency of each train differs across the entire track considered in this study. The results of this study are expected to facilitate objective and practical planning during railway construction.

scholarly journals Risks of Ear Complaints of Passengers and Drivers While Trains Are Passing Through Tunnels at High Speed: A Numerical Simulation and Experimental Study

2019 ◽  
Vol 16 (7) ◽  
pp. 1283 ◽  
Author(s):  
Pengpeng Xie ◽  
Yong Peng ◽  
Tiantian Wang ◽  
Honghao Zhang
Keyword(s):  
High Speed ◽  
Fe Model ◽  
Analysis Method ◽  
High Speed Train ◽  
Pressure Transients ◽  
Operation Speed ◽  
High Speed Trains ◽  
Recorded Data ◽  
Four Levels ◽  
Human Middle Ear

Ear complaints induced by interior pressure transients are common experiences for passengers and crew members when high-speed trains are passing through tunnels. However, approaches to assessing the risks of the pressure-related aural discomfort have not been reported until recently. The objective of this study was to evaluate the hazards of interior pressure transients of high-speed train on human ears combining the effects of operation speed and seal index. Moving model tests were conducted to obtain the pressure transients when the model train runs in the tunnel. The recorded data were transformed into the interior pressures by empirical formula. Furthermore, the aural sensations were divided into four levels hierarchically and the range for each level was derived by logistic regression analysis method and represented by three biomechanical metrics. Furthermore, a human middle ear finite element (FE) model was used to simulate its dynamics under the interior pressures. The results indicate that lifting operation speed from 250 km/h to 350 km/h in tunnel will prolong the duration of ear complaints by more than two times whereas improving the seal index from 4 s to 12 s will reduce the incidences of the onset of tinnitus and hearing loss by more than ten times. In addition, the duration of aural comfort shortens from the head car to the tail car against the running direction. It is desirable that enhancing the seal index improve the aural sensations of the passengers and crew members considering the lifting operation speed of high-speed train.

Key Issues on Train Line Planning for Beijing-Shanghai High Speed Railway

2010 ◽  
Author(s):  
L. Nie ◽  
D. B. Fei ◽  
S. D. Zhou ◽  
H. L. Fu ◽  
L. Tong
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Travel Demand ◽  
Time Window ◽  
Long Distance ◽  
Line Planning ◽  
High Speed Railway ◽  
Passenger Flow ◽  
Train Operation ◽  
Service Plan

The Beijing-Shanghai High speed railway line (Hereinafter referred to as “Jing-Hu HSL”) is one of the most important railway lines in the Chinese rapid passenger transportation network and will be put into operation at the end of 2011. Train line planning directly reflects the quality and competition ability of train services. The characteristics of operational conditions and passenger flow of this corridor HSL bring about a few new issues on train line planning like night train operation, train OD sets, cyclic operation, and train stop schedule. For the first issue, a large amount of long distance travel demand put forward the demand for night services, which causes great conflict with the time-window for maintenance work. The confliction can be solved by harmoniously utilizing the parallel lines. For the second one, in view of the differences of technical and economic factors between HSL and conventional railways, high frequency and medium-long distance train will dominate HSL’s train service plan rather than low frequency and long distance trains on conventional railways. Thus, part of long-distance passenger flow has to transfer at some stations. Considering the whole possible ODs over Jing-Hu HSL and the transfer condition of related stations, the optimal OD sets and corresponding transfer plan is suggested. High frequency makes HSL possible to operate trains cyclically to improve service quality. However, with too many train ODs and some special trains, e.g. night train, an incomplete cyclic train operation mode is more practical. The ODs which can provide cyclic service for Jing-Hu HSL need to be identified. For the last issue, although non-stop long-distance train is a very popular kind of service in China, it should be reconsidered for Jing-Hu HSL line because of massive intercity travel demand and regular stops required. Each of the above issues is very complex. What is more, they have close relationship between each other. Due to limited space, the methods used to solve these issues are given in conceptual way rather than detailed description of mathematical model. The research paves the way for future integration study to design an efficient, economic, convenient, and regular train service plan for Jing-Hu HSL.

scholarly journals Structural Improvement of the ω-Type High-Speed Rail Clip Based on a Study of Its Failure Mechanism

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Xiaogang Gao ◽  
Anbin Wang ◽  
Yu He ◽  
Xiaohan Gu
Keyword(s):  
Failure Mechanism ◽  
Fatigue Test ◽  
High Frequency ◽  
High Speed ◽  
Excitation Frequency ◽  
Test System ◽  
Vibration Measurement ◽  
High Speed Rail ◽  
Resonant Frequencies ◽  
Rail Wear

In the circumstances of high-speed railways, the wheel-rail vibration is significantly aggravated by polygonal wheel wear and rail corrugation, which subsequently leads to the wheel-rail interaction at higher frequencies and potential failure of the rail fastening. In this paper, a ω-type clip of the fastening in the CRH high-speed rail was used to investigate the failure mechanism. First, a dynamic wheel-rail coupling model and a finite element analysis of the rail clip were developed, from which the rail vibration frequency and modal frequencies of the clip with different installation torques were obtained. The experimental tests and modal simulation results were mutually verified. In addition, the real-time vibration measurement and the wheel-rail wear monitoring were carried out at a CRH high-speed railway site. It was found that the resonant frequencies of the ω-type clip in the installation condition coincided with the excitation frequencies of the wheel-rail interaction induced by wheel-rail wear. The high-frequency dynamic failure mechanism of a typical ω-type clip, W300-1, is put forward for the first time. Moreover, a high-frequency rail clip fatigue test system was designed and developed specifically for this study. The loading excitation frequency of the clip test used was set as 590 Hz, and the loading amplitude was 0.05 mm. After 125-minute operation of the test system, the clip was broken at the expected location predicted by the FEA model. The high-frequency fatigue test result further verified that the failure mechanism of the ω-type clip was due to the resonance of the clip with its excitation force from the wheel-rail interaction. Finally, the clip was then structurally improved taking into account the stiffness and mass, which led to its resonant frequencies shifting away from the high-frequency excitation range, hence avoiding resonance failure of the subject clip.

scholarly journals Observer Based Traction/Braking Control Design for High Speed Trains Considering Adhesion Nonlinearity

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Wenchuan Cai ◽  
Wenhao Liao ◽  
Danyong Li ◽  
Yongduan Song
Keyword(s):  
High Speed ◽  
Adhesion Force ◽  
Surface Condition ◽  
Control Design ◽  
Work Force ◽  
High Speed Trains ◽  
Train Operation ◽  
Braking Control ◽  
Key Enabling Technologies ◽  
Automatic Train Operation

Train traction/braking control, one of the key enabling technologies for automatic train operation, literally takes its action through adhesion force. However, adhesion coefficient of high speed train (HST) is uncertain in general because it varies with wheel-rail surface condition and running speed; thus, it is extremely difficult to be measured, which makes traction/braking control design and implementation of HSTs greatly challenging. In this work, force observers are applied to estimate the adhesion force or/and the resistance, based on which simple traction/braking control schemes are established under the consideration of actual wheel-rail adhesion condition. It is shown that the proposed controllers have simple structure and can be easily implemented from real applications. Numerical simulation also validates the effectiveness of the proposed control scheme.

scholarly journals Research on the Vibration Insulation of High-Speed Train Bogies in Mid and High Frequency

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Jia Liu ◽  
Xuesong Jin
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Structure Design ◽  
High Speed Train ◽  
Bogie Frame ◽  
Explicit Finite Element ◽  
Vibration Transmissibility ◽  
Structure Improvement ◽  
Polygonal Wear ◽  
Stiffness And Damping

According to a large amount of the test data, the mid and high frequency vibrations of high-speed bogies are very notable, especially in the 565~616 Hz range, which are just the passing frequencies corresponding to the 22nd to 24th polygonal wear of the wheel. In order to investigate the main cause of wheel higher-order polygon formation, a 3D flexible model of a Chinese high-speed train bogie is developed using the explicit finite element method. The results show that the couple vibration of bogie and wheelset may lead to the high-order wears of wheel. In order to reduce the coupled resonance of the wheelset and the bogie frame, the effects of the stiffness and damping of the primary suspensions, wheelset axle radius, and bogie frame strength on the vibration transmissibility are discussed carefully. The numerical results show that the resonance peaks in high frequency range can be reduced by reducing the stiffness of axle box rotary arm joint, reducing the wheelset axle radius or strengthening the bogie frame location. The related results may provide a reference for structure improvement of the existing bogies and structure design of the new high-speed bogies.

scholarly journals Numerical Modeling and Investigation on Aerodynamic Noise Characteristics of Pantographs in High-Speed Trains

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Xiaoqi Sun ◽  
Han Xiao
Keyword(s):  
High Frequency ◽  
High Speed ◽  
Sound Pressure ◽  
Noise Source ◽  
Flow Fields ◽  
Aerodynamic Noise ◽  
Far Field ◽  
Frequency Bands ◽  
Noise Characteristics ◽  
High Speed Trains

Pantographs are important devices on high-speed trains. When a train runs at a high speed, concave and convex parts of the train cause serious airflow disturbances and result in flow separation, eddy shedding, and breakdown. A strong fluctuation pressure field will be caused and transformed into aerodynamic noises. When high-speed trains reach 300 km/h, aerodynamic noises become the main noise source. Aerodynamic noises of pantographs occupy a large proportion in far-field aerodynamic noises of the whole train. Therefore, the problem of aerodynamic noises for pantographs is outstanding among many aerodynamics problems. This paper applies Detached Eddy Simulation (DES) to conducting numerical simulations of flow fields around pantographs of high-speed trains which run in the open air. Time-domain characteristics, frequency-domain characteristics, and unsteady flow fields of aerodynamic noises for pantographs are obtained. The acoustic boundary element method is used to study noise radiation characteristics of pantographs. Results indicate that eddies with different rotation directions and different scales are in regions such as pantograph heads, hinge joints, bottom frames, and insulators, while larger eddies are on pantograph heads and bottom frames. These eddies affect fluctuation pressures of pantographs to form aerodynamic noise sources. Slide plates, pantograph heads, balance rods, insulators, bottom frames, and push rods are the main aerodynamic noise source of pantographs. Radiated energies of pantographs are mainly in mid-frequency and high-frequency bands. In high-frequency bands, the far-field aerodynamic noise of pantographs is mainly contributed by the pantograph head. Single-frequency noises are in the far-field aerodynamic noise of pantographs, where main frequencies are 293 Hz, 586 Hz, 880 Hz, and 1173 Hz. The farther the observed point is from the noise source, the faster the sound pressure attenuation will be. When the distance of two adjacent observed points is increased by double, the attenuation amplitude of sound pressure levels for pantographs is around 6.6 dB.

scholarly journals Review and prospect of maintenance technology for traction system of high-speed train

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Shaolong Xu ◽  
Chunyang Chen ◽  
Zhenjun Lin ◽  
Xiao Zhang ◽  
Jisheng Dai ◽  
...  
Keyword(s):  
High Speed ◽  
Research Direction ◽  
Maintenance Cost ◽  
High Speed Train ◽  
Transportation Industry ◽  
Key Factors ◽  
The World ◽  
High Speed Trains ◽  
Oil Crisis ◽  
Traction System

Abstract In the past few decades, high-speed trains have witnessed tremendous and vigorous development with the appearance of the oil crisis and industrialization, which became a significant trend in the transportation industry the world over. With the increase of high-speed railway mileage, the amount of high-speed train has grown sharply, the service life of the trains has increased gradually and the components of the vehicle traction system have become worn and aged as a result. Therefore, advanced maintenance technology and its application are key factors to reduce maintenance cost, human resource input and ensure safe, stable and reliable operation of trains. This paper summarizes and discusses the development, application mode, maintenance management and maintenance technology of high-speed railways of the major countries in the world, especially discusses the condition-based maintenance and the key technology of the traction electrical system, and offers the prospect of research direction and the development of traction maintenance technology.

Experimental and numerical analysis of the polygonal wear of high-speed trains

Wear ◽  
2019 ◽  
Vol 440-441 ◽  
pp. 203079 ◽  
Author(s):  
Wubin Cai ◽  
Maoru Chi ◽  
Xingwen Wu ◽  
Fei Li ◽  
Zefeng Wen ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
High Speed ◽  
High Speed Trains ◽  
Polygonal Wear
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