Table of Content

25 February 2021, Volume 32 Issue 04

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Thoughts on Health Management and Condition-based Maintenance of Rolling Stocks

ZHANG Weihua, LI Quanfu, SONG Dongli

2021, 32(04):  379-389.  DOI: 10.3969/j.issn.1004-132X.2021.04.001

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In order to ensure the safety of operation, reduce the maintenance cost of railway rolling stocks, and improve the availability of rolling stocks, health management and condition-based maintenance were highly valued by railway rolling stock operation departments.The developments of the maintenance process and system of railway rolling stocks were summaried, and a reasonable determination of the criteria for the status evaluation and classification of rolling stocks was made, and the status were divided into three types: basic status, performance status and safety status. According to the status of the rolling stock, based on the previous research experience and combined with the development of technology, some suggestions and matters needing attention for rolling stock detection status were put forward. At present, there were many difficulties in life prediction. Based on the status and detection method of rolling stocks , a residual life prediction scheme and reform direction of maintenance process and system  were put forward, in order to promote the development of health management and condition repair of railway rolling stocks  and vehicles.

Reliability Analysis of Train Control Center Based on Discrete-time Bayesian Network

WANG Kang, QI Jinping, ZHOU Yahui, LI Shaoxiong, ZHAO Ruihu, GUO Hao

2021, 32(04):  390-398.  DOI: 10.3969/j.issn.1004-132X.2021.04.002

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Aiming at the problems that the faults of electric multiple units train control center were both polymorphism and dynamic in actual working environment, an analysis method of discrete-time Bayesian network was proposed based on the functional logic relationship of each unit in the train control center. The multi-state characteristics of train control center fault were described by summarizing various fault modes of components, and the condition probability table was optimized by EM algorithm. Aiming at the dynamic failure of train control center, a dynamic Bayesian network model was established, then a task was divided into three stages: start, operation and braking. In each stage, the reliability of the model was analyzed by importance and sensitivity. Finally, the train control center of the CTCS-2 train control system was taken as an example to verify and analyze the discrete-time Bayesian network model, proving that the method may characterize the polymorphism and dynamic characteristics of train control center well.

Multi-level Imperfect Maintenance Strategy for EMU Components from Perspective of Failure Risks

XIONG Lü , WANG Hong

2021, 32(04):  399-406.  DOI: 10.3969/j.issn.1004-132X.2021.04.003

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In order to reduce the total maintenance costs of EMU components in a life cycle, a preventive maintenance optimization strategy of EMU components was established based on multi-level imperfect maintenance mechanism under the current hierarchical maintenance mechanism of EMU in China, taking the components that needed to be replaced during the five-level maintenance of EMU as the research object, taking the impacts of failures on the operation safety of EMU, the impacts of failures on the delay of EMU and the difficulty of failure maintenances as the evaluation index of failure risks, the weight of each influencing factor was determined by analytic hierarchy process, and each influencing factor was scored, and the failure risks of EMU components were quantitatively evaluated. The imperfect maintenance modes of EMU components were divided into multi levels, primary maintenance, intermediate maintenance and advanced maintenance, which overcome the shortcomings of the former model that the imperfect maintenance mode was single and ignored the practical maintenance which the multi-level imperfect maintenance mode was commonly used. The simulation results show that the proposed maintenance strategy may maintain a higher reliability level and reduce the total costs of EMU component in a life cycle.

Intelligent Maintenance Technology and Equipment for Medium-low Speed Maglev Lines

ZONG Bin, LIU Feixiang, ZHANG Kun, ZHANG Yinlong

2021, 32(04):  407-411.  DOI: 10.3969/j.issn.1004-132X.2021.04.004

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To study the intelligent maintenance technology and equipment for medium-low speed maglev lines， the special equipment of medium-low speed maglev lines was investigated, the influences of track comfort index on maglev train were analyzed, and combined with the operation and maintenance of the line, the key contents and cycle of line maintenances were put forward. Based on the research and analysis conclusions, series of customized equipment and system schemes for intelligent maintenance were put forward, which included maglev line intelligent patrol operation vehicle, F-rail integrated operation vehicle, special operation platform vehicle, intelligent operation and maintenance management system, and the automatic and intelligent scheme, which may effectively improve the operating efficiency, reduce labor cost and improve the safety of medium-low speed maglev line maintenance.

Effects of Leading Edge of Friction Block on Braking Properties of High-speed Railway Brakes

TANG Bin, FAN Zhiyong, XIANG Zaiyu, WU Yuanke, Huang Bo, MO Jiliang,

2021, 32(04):  412-419.  DOI: 10.3969/j.issn.1004-132X.2021.04.005

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Based on a small-scale self-design brake test bench for high-speed trains, the drag-type brake tests of triangular friction blocks were conducted with four different mounting directions. The effects of the leading edge features of friction blocks on the braking properties was investigated, and the distribution characteristics of contact pressures on block surfaces under different mounting directions were analyzed by finite element method. The potential relationship among the contact pressure distribution, thermal distribution, and vibration and noise properties was explored. The results show that the contact pressure always concentrate on the leading edges of friction surfaces in the friction braking processes. When the friction block getting two leading edges involved, i.e., one corner of the friction block firstly entering the friction area, severer concentrated stress at leading edges may be observed, which induces high-intensity vibration and noise of the brake systems as well as high temperature in partial areas of block surfaces.

Study on Influence Parameters of Rail Corrugation on Tangential Tracks of Metro

WANG Zhiqiang, , LEI Zhenyu,

2021, 32(04):  420-430.  DOI: 10.3969/j.issn.1004-132X.2021.04.006

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The influences of different track structure parameters and the vehicle operation speeds on the generation and development of rail corrugation on the tangential tracks of metro were analyzed based on the vehicle-track coupled dynamics model and the rail material friction and wear calculation model. The results show that, for different variable parameters, the friction power in wheel-rail contact patch fluctuates with time, and the overall fluctuation range of friction power is relatively uniform. At the same time, the analysis results of one-third octave curves of friction power show that the characteristic frequencies of friction power are mainly concentrated in the middle and low frequency ranges. At the main characteristic frequency, the longitudinal stiffness of fasteners, the longitudinal damping of fasteners, the transverse damping of fasteners and the vertical damping of fasteners have less influence on rail corrugation, while the transverse stiffness of fasteners, the vertical stiffness of fasteners, the spacing of fasteners, the wheel-rail friction coefficient and the running speed of vehicles have greater influence on rail corrugation. Changes in the vertical stiffness and spacing of fasteners will cause the characteristic frequency of friction power to be offset (the main characteristic frequency is shifted from 80 Hz to 100 Hz), which will lead to rail corrugation of corresponding wavelength, indicating that the vertical stiffness and spacing of fasteners have an important impact on the generation and development of rail corrugation at the specific frequency. The increase of other variables does not change the characteristic frequency of friction power, indicating that the other variables do not affect the characteristic frequency of rail corrugation.

Temperature Distribution of Treads and Wear Prediction during Train Emergency Braking

DONG Yonggang, YI Shuai, HUANG Xinlei, SONG Jianfeng, DU Xiaozhong

2021, 32(04):  431-438,445.  DOI: 10.3969/j.issn.1004-132X.2021.04.007

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The rapid increases of tread temperature during the emergency braking processes of the trains caused the friction and wear mechanism of the wheel tread to be significantly different from that during steady state operations. In order to accurately predict the wear of the trains emergency braking tread, the wheel tread contact with the rail and the brake shoe was also considered during the tread braking processes, the thermal-mechanical coupling finite element model of tread braking processes was established based on ABAQUS finite element software, the impacts of braking temperature rise on the mechanical properties, hardness and friction coefficient of the wheel treads were comprehensively considered,  the temperature distribution, hardness distribution and contact stress distribution on the wheel tread during emergency braking were obtained by simulation, the wheel-rail dynamics software UM was used to obtain the wheel-rail contact spot shapes and the wheel-rail creep area relative slip distribution during the emergency braking processes. Then, the Archard wear model wass used to determine the tread wear depth after a single emergency braking with quantitative predictions. The results show that for the two working conditions of the initial braking speed of 130 km/h and 160 km/h, the highest tread temperature reach 397.0 ℃ and 4859 ℃ respectively, the cumulative maximum wear depthes of the tread are 590 μm and 7.43 μm, respectively. Compared with the tread braking experiments, it is found that the wear position and topography distribution trend are consistent.

Research on Low Floor Tram Wheel and Rail Wear under Resilient Wheels

YANG Yang, SHEN Jian, WANG Kongming, ZHAN Jun

2021, 32(04):  439-445.  DOI: 10.3969/j.issn.1004-132X.2021.04.008

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In order to study the wear of vehicle treads with resilient wheels and rails of running resilient wheels, a prediction model of wheel and rail wear was established based on Archard wear model. The wear situations of wheel treads and rails were analyzed under different track irregularity conditions and curve radius conditions. Comparing and analyzing the resilient wheels and rigid wheels the results show that, the resilient wheels have better wear reduction effectiveness when the track is poor. The wear reduction effectiveness of resilient wheels on the track with smaller curve radius is smaller. With the increasing of curve radius, the wear reduction effectiveness of resilient wheels is obvious. Compared with running rigid wheels, the maximum cumulative wear of rails is reduced by 33% when running resilient wheels. The resilient wheels may reduce the wear of curved rails to some extents.

A Detecting Method for Structure Crack Edges of Municipal Railway  Tunnels under Supervised Learning

ZHANG Kun, CHEN Dingfang, GAO Mingxin, HUANG Yongliang, LIU Yang, MEN Yanqing

2021, 32(04):  446-453.  DOI: 10.3969/j.issn.1004-132X.2021.04.009

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Regular inspection of crack diseases was the key to ensure the normal operation of metro tunnel structures. To address this issue, a method for crack detection of metro tunnel structures under supervised learning was proposed herein. Firstly, the images of the metro tunnel structures were obtained by a consumer digital camera. Secondly, the geometric feature vectors of the edge targets were constructed based on the preliminary detection results by Canny operator, and then the crack edges of metro tunnel structures were detected by using the geometric feature vectors of edge targets. Finally, the effectiveness of the proposed method was verified by the image data of the metro tunnel structures.

High Speed Track Defect Detection Methods Based on Enhanced  Magnetic Field Eddy Currents

XU Peng, ZENG Hongming, ZHU Chenlu, WANG Ping, GENG Ming, XU Yong

2021, 32(04):  454-459,466.  DOI: 10.3969/j.issn.1004-132X.2021.04.010

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In the field of high-speed rail transport, eddy current detections were widely used in the detection of rail surface defects because of non-contact, easy to achieve automation and other characteristics. However, due to the skin effect, it was difficult to detect the internal damages by eddy current testing. A method to enhance the magnetic field eddy currents to suppress the skin effect was proposed: a U-shaped electromagnet with a direct current was added to the eddy current detection coils, and the magnetic yoke was used to conduct magnetism to the steel rail to enhance the magnetic field under the yoke. Through the finite element simulation by ANSYS, the changes of eddy current penetration depths after the enhancement of magnetic field were analyzed. And the influences of yoke lift and distance on the detection effectiveness were simulated. An experimental platform of high-speed track detections was built, and the experiments of enhanced magnetic field eddy currents was carried out. The results show that appropriate background magnetic field enhancement may make eddy current detections have the ability of internal defect detections and improve the signal-to-noise ratio of detection signals.

Research on Mounting Life of Subway Supports Based on  Damage Association Editing Method

CHEN Kuanyu, YANG Guangwu, XIAO Shoune, WANG Jujin

2021, 32(04):  460-466.  DOI: 10.3969/j.issn.1004-132X.2021.04.011

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A method for compiling the load spectrum of aluminum alloy welding seams was proposed by taking the antenna mounting bases of subway bottom frame as the research objects. The acceleration parameters were selected based on the theory of multi-channel damage association editing, and the accelerating excitation spectrum was constructed under the condition of the most consistent preset damage and pseudo damage. The acceleration effectiveness is obvious and the error of each basic characteristic parameter may be controlled within 5% by analyzing the time-domain and frequency-domain characteristics of the target spectrum. The simulation results show that the fatigue life error is within 10% and the reduced efficiency is good by finite element model and the method of quasi-static superposition and uniaxial response,which verified the rationality of the method. The data of bench simulation long life tests show that this method may save more than 40% of test time and the error can be controlled within 15% after using the prepared load spectrum.This method may be used as a reference for compiling the load spectrum of other equipment.

Design and Implementation of Maglev Trains Levitation Data Acquisition System

YANG Fan, LI Jingwei, LI Yiguo, BI Tao

2021, 32(04):  467-474.  DOI: 10.3969/j.issn.1004-132X.2021.04.012

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The comfort and safety and reliability of maglev train mainly depended on the suspension control system, which was one of the key components of maglev trains. A data acquisition system in suspension states was designed for medium and low speed maglev trains,the system was independent of the train suspension control systems. The data collector was fixed on the suspension frame at the bottom of the maglev trains, which didnt affect the traffic safety. The suspension current, electromagnet temperature, suspension clearance, suspension frame vibration acceleration and sensor signal data were collected and analyzed by the system. The basic research data are provided for studying adaptability of suspension control system to line conditions, vehicle dynamic and static loads, extreme climate and the reliability of suspension control equipment.

Key Technologies of Smart Platform Door Systems of Urban Railways

ZHANG Yinlong

2021, 32(04):  475-480.  DOI: 10.3969/j.issn.1004-132X.2021.04.013

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In view of the status of the mixed running of various train types faced by platform doors in urban railways, and the impacts of the wind pressures of the train passing through the stations on the platform door, the key technologies and solutions of smart platform door systems were proposed. Based on the lifting platform door technology, the compatibility of door positions of various types was realized, the intelligent guidance of passenger boarding and alighting was realized by using intelligent waiting guidance technology, and the preventive maintenance and reliable operation of equipment were realized by using intelligent operation and maintenance technology. An incompressible three-dimensional unsteady turbulent model of gas flow in the station sections was constructed, and the flow characteristics in the processes of high-speed passing through the stations were simulated and analyzed. The impacts of wind pressure on the platform door under different passing speeds were solved by numerical simulation, and verified by experiments. The research results show that when the train passing speed reaches 220 km/h, the maximum piston wind pressure is as 1913 Pa at 1.2 m away from the platform edge, which is less than the design allowable pressure of 2050 Pa. The reliability of the platform door systems was proved by simulation and tests.

Numerical Analysis and Experimental Study of Particle Dampers for Vibration Reduction of EMU End Wall Structures

XIAO Wangqiang, YE Shuzhen, WANG Xingming, JIA Shangshuai, PAN Dekuo, LU Dajun,

2021, 32(04):  481-489.  DOI: 10.3969/j.issn.1004-132X.2021.04.014

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The vibration and radiation noise of EMU end wall structures affected the ride comfort and the train stability during high-speed operation, and even caused structural fatigue failure. For the abnormal vibration problems of end wall structures at 40 Hz excitation frequency, a vibration reduction method for end walls was proposed based on particle damping technology. A discrete element model of the end wall particle dampers was established. The layout schemes and layer numbers were optimized according to the energy dissipation of the particle systems. And experiments were performed to analyse the acceleration responses of the end walls of each vibration-absorbing scheme. The experimental data indicate that the vibration reduction rate of the end walls in the main vibration direction may reach more than 80% at 40 Hz excitation frequency after the installation of particle dampers. The validity of the theory and simulation model was verified by experiments.

Multidisciplinary Design Optimization of High-speed Pantograph  Based on Collaborative Optimization Algorithm

ZHANG Jing, CHENG Feifei, SONG Baolin, LIU Zhigang, ZHANG Weihua

2021, 32(04):  490-498.  DOI: 10.3969/j.issn.1004-132X.2021.04.015

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Considering the influences of interaction and coupling among various disciplines on the design optimization of pantographs, the design demands of different working properties were analyzed. The multidisciplinary design optimization was adopted to establish optimization models of the system and subsystems that include the kinematics, statics, dynamics and control. According to the coupling relationship of design parameters of different disciplines, the collaborative optimization method was adopted to obtain the overall design optimization results of high-speed pantograph. The three-dimensional model of the pantograph was established to verify the validity of the optimized results by ANSYS. The results show that the multidisciplinary collaborative design meets the design requirements of the system and subsystems, and obtain the overall optimal solutions of the pantograph, which enhances the performance of the pantograph, reduces the fluctuation of the contact forces and increases the current collection quality of the pantograph and catenary.

Design and Operation Safety Guarantee Technology for  Suburban Railway Passenger Lifting Equipment

LI Chengyang

2021, 32(04):  499-503.  DOI: 10.3969/j.issn.1004-132X.2021.04.016

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In order to solve the problems of information disconnection and high reliability requirements in the design processes of passenger lifting equipment, a concept of data-driven application was proposed. Based on the intelligent design method of event-condition-action (ECA) rule and case-based reasoning (CBR) technology, an intelligent design system was established throughout the whole stages of passenger lifting equipment designs and operations. Meanwhile, in order to solve the problems of many kinds of faults, easy to expand and difficult to prevent and control, the operation safety monitoring technology was studied based on internet of things(IOT)sensors. An effective scheme was provided to ensure the safety of passenger lifting equipment from the design stages to the operation stages.