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Abnormal Vertical Dynamic Performance of Subway Vehicles

Chinese Journal of Mechanical Engineering 2010年第2期23卷 174-179页

作者： MA Weihua LUO Shihui SONG Rongrong Traction Power State Key Laboratory Southwest Jiaotong University Chengdu 610031 China csr ziyang locomotive co. Ltd. Ziyang 641301 China co.lege of co.puter Science and Technology Southwest University for Nationalities Chengdu 610041 China

A serious wheel out-of-round phenomenon exists in a certain subway vehicle in China. More seriously, the vertical vibration of car body of this subway vehicle will go beyond the restriction of the standard criterion when the wheel out-of-round exceeds 0.2 mm in radial direction. And the wheel out-of-round problem co.ld not be solved by polishing the rail or re-profiling wheels. Aimed at this problem, a further analysis is co.ducted on the structure and the suspension systems of the subway vehicle. It is thought that the additional stiffness function of the traction bar, caused by the short length and the bigger co.nection stiffness of the traction bar, leads to the problem that the subway vehicle is sensitive to the vertical impact. By taking into acco.nt the stiffness of the traction bar, dynamic simulation models of the subway vehicle are set up to study the influence of the additional stiffness function of the traction bar on the vertical dynamic performance of the subway vehicle through the simulation method. The response of the subway vehicle to vertical impact of a triangle pitch is also simulated. Simulation results indicate that the co.nection between the car body and the bogie will beco.e rigid and the damping function of the seco.dary suspension will be decreased due to the additional stiffness of the traction bar in braking co.dition or running on curve track. Then the vertical response of the car body to vertical impact will be strengthened and the vertical ride index decreased. The vertical dynamic performance of the subway vehicle will be improved through the method of decreasing the co.nection stiffness of the traction bar, which has been validated by the simulation results. This method of improvement can effectively solve the problem of abnormal dynamic performance of this subway vehicle, and provide a foundation for a new theory about the traction bar system design.

关键词： subway wheel set tread out-of-round dynamic

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Assembly Auxiliary System for Narrow Cabins of Spacecraft

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Chinese Journal of Mechanical Engineering 2015年第5期28卷 1080-1088页

作者： LIU Yi LI Shiqi WANG Junfeng School of Mechanical Science & Engineering Huazhong University of Science and Technology csr Zhuzhou Electric locomotive co. Ltd.

Due to the narrow space and co.plex structure of spacecraft cabin, the existing asssembly systems can not well suit for the assembly process of cabin products. This paper aims to introduce an assembly auxiliary system for cabin products. A hierarchical-classification method is proposed to re-adjust the initial assembly relationship of cabin into a new hierarchical structure for efficient assembly planning. An improved ant co.ony algorithm based on three assembly principles is established for searching a optimizational assembly sequence of cabin parts. A mixed reality assembly environment is co.structed with enhanced inforamtion to promote interaction efficiency of assembly training and guidance. Based on the machine vision technology, the inspection of left redundant objects and measurement of parts distance in inner cabin are efficiently performed. The proposed system has been applied to the assembly work of a spacecraft cabin with 107 parts, which includes cabin assembly planning, assembly training and assembly quality inspection. The application result indicates that the proposed system can be an effective assistant tool to cabin assembly works and provide an intuitive and real assembly experience for workers. This paper presents an assembly auxiliary system for spacecraft cabin products, which can provide technical support to the spacecraft cabin assembly industry.

关键词： assembly planning hierarchical-classification ant co.ony algorithm augmented reality visual inspection

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Aerodynamic design on high-speed trains

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Acta Mechanica Sinica 2016年第2期32卷 215-232页

作者： San-San Ding Qiang Li Ai-Qin Tian Jian Du Jia-Li Liu School of Mechanical Electronic and Control EngineeringBeijing Jiaotong University csr Qingdao Sifang locomotive & Rolling Stock co. Ltd.

co.pared with the traditional train,the operational speed of the high-speed train has largely improved,and thedynamicenvironmentofthetrainhaschangedfromoneof mechanical domination to one of aerodynamic *** aerodynamic problem has beco.e the key technological challenge of high-speed trains and significantl affects the eco.omy,environment,safety,and *** this paper,the relationships among the aerodynamic design principle,aerodynamic performance indexes,and design variables are firs studied,and the research methods of train aerodynamics are proposed,including numerical simulation,a reducedscale test,and a full-scale *** schemes of train aerodynamics involve the optimization design of the streamlined head and the smooth design of the body *** design of the streamlined head includes co.ception design,project design,numerical simulation,and a reduced-scale *** design of the body surface is mainly used for the key parts,such as electric-current co.lecting system,wheel truck co.partment,and *** aerodynamic design method established in this paper has been successfully applied to various high-speed trains（CRH380A,CRH380 AM,CRH6,CRH2 G,and the Standard electric multiple unit（EMU）） that have met expected design *** research results can provide an effective guideline for the aerodynamic design of high-speed trains.

关键词： High-speed train Aerodynamic design Optimization design Smooth design

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Sintering behavior of Cr in different atmospheres and its effect on the microstructure and properties of co.per-based co.posite materials

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International Journal of Minerals,Metallurgy and Materials 2013年第12期20卷 1208-1213页

作者： Ye Wang Qing-zhi Yan Fei-fei Zhang Chang-chun Ge Xiao-lu Zhang Hai-qin Zhao Laboratory of Special Ceramics and Powder Metallurgy University of Science and Technology Beijing Beijing Railway Star Fortune Technology co. Ltd. csr Qingdao Sifang locomotive & Rolling Stock co. Ltd.

co.per matrix co.posites co.sisting of chromium （Cr） or ferrochrome （Cr-Fe） as strengthening elements and molybdenum disulfide as a lubricant had been sintered in nitrogen and hydrogen atmosphere, respectively. Their morphology and energy-dispersive X-ray spectrometry （EDS） analysis showed that serious interaction occurred between MoS2 and Cr （or Cr-Fe） particles when the samples were sintered in hydrogen atmosphere. Chromium sulfide co.pound （CrxSy） was formed as a reaction product, which decreased the density and strength of the co.posites remarkably. This interaction was inhibited when the samples were sintered in nitrogen atmosphere; thus, the mechanical properties of the co.posites were improved.

关键词： metallic matrix co.posites microstructure mechanical properties chromium ferrochrome sintering

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Numerical study on wake characteristics of high-speed trains

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Acta Mechanica Sinica 2013年第6期29卷 811-822页

作者： Shuan-Bao Yao Zhen-Xu Sun Di-Long Guo Da-Wei Chen Guo-Wei Yang Key Laboratory for Mechanics in Fluid Solid co.pling Systems Institute of MechanicsCAS csr Qingdao Sifang locomotive co.Ltd.

Intensive turbulence exists in the wakes of high speed trains, and the aerodynamic performance of the trailing car co.ld deteriorate rapidly due to co.plicated features of the vortices in the wake zone. As a result, the safety and amenity of high speed trains would face a great challenge. This paper co.siders mainly the mechanism of vortex formation and evolution in the train flow field. A real CRH2 model is studied, with a leading car, a middle car and a trailing car included. Different running speeds and cross wind co.ditions are co.sidered, and the approaches of un- steady Reynold-averaged Navier-Stokes （URANS） and de- tached eddy simulation （DES） are utilized, respectively. Re- suits reveal that DES has better capability of capturing small eddies co.pared to URANS. However, for large eddies, the effects of two approaches are almost the same. In co.ditions without cross winds, two large vortex streets stretch from the train nose and interact strongly with each other in the wake zone. With the reinforcement of the ground, a co.plicated wake vortex system generates and beco.es strengthened as the running speed increases. However, the locations of flow separations on the train surface and the separation mechanism keep unchanged. In co.ditions with cross winds, three large vortices develop along the leeward side of the train, among which the weakest one has no obvious influence on the wake flow while the other two stretch to the tail of the train and co.bine with the helical vortices in the train wake. Thus, optimization of the aerodynamic performance of the trailing car should be aiming at reducing the intensity of the wake vortex system.

关键词： Wake flow structures URANS DES High speed trains

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Effect of Mg-based spherical quasicrystal on microstructures and mechanical properties of ZA54 alloy

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Transactions of Nonferrous Metals Society of China 2010年第7期20卷 1199-1204页

作者：张金山张永青张焱许春香王晓明严杰 co.lege of Materials Science and Engineering Taiyuan University of Technology csr Qishuyan locomotive and Rolling Stock Technology Research Institute co.Ltd.

To improve the strength, toughness and heat-resistance of magnesium alloy, the microstrucmre and mechanical properties of ZA54 alloy reinforced by ico.ahedral quasicrystal phase （/-phase） particles were studied. Except α-Mg, φ-phase and τ-phase, MgZnYMn I-phase particles can be obtained in ZA54-based co.posites by the addition of ico.ahedral quasicrystal-co.tained Mg-Zn-Y-Mn master alloy. The introduction of MgZnYMn I-phase into ZA54 alloy has great co.tribution to the refinement of matrix microstructures and the improvement of mechanical properties. When the addition of Mg-based spherical quasicrystal master alloy is up to 3.5% （mass fraction）, the macro-hardness of ZA54-based co.posites is increased to HB 68. The impact toughness of co.posites reaches the peak value of 18.3 J/cm^2, which is about 29% higher than that of ZA54 mother alloy. The highest tensile properties at ambient and elevated temperatures with master alloy addition of 2.5% （473 K） are also obtained in ZA54-based co.posites with 3.5% （mass fraction） Mg-Zn-Y-Mn master alloy addition. The ultimate tensile strength of co.posites at ambient and elevated temperatures are 192.5 MPa and 174 MPa, which are 23.4% and 33.8% higher than that of ZA54 mother alloy, respectively. The improved mechanical properties are mainly attributed to the pinning effect of I-phase on grain boundaries.

关键词： magnesium alloy spherical quasicrystal particles ZA54 alloy co.posite strengthening heat-resistance ~: magnesium alloy spherical quasicrystal particles ZA54 alloy co.posite strengthening heat-resistance

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Annealing temperature influence on the degree of inhomogeneity of the Schottky barrier in Ti/4H–SiC co.tacts

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Chinese Physics B 2014年第12期23卷 418-422页

作者：韩林超申华军刘可安王弋宇汤益丹白云许恒宇吴煜东刘新宇 Microwave Device and IC Department Institute of Microelectronics Chinese Academy of Sciences Zhuzhou csr Times Electric co. Ltd Zhuzhou csr Times Electric co. Ltd

Tung＇s model was used to analyze anomalies observed in Ti/Si C Schottky co.tacts. The degree of the inhomogeneous Schottky barrier after annealing at different temperatures is characterized by the ‘T0anomaly＇ and the difference（△Φ）between the uniformly high barrier height（Φ0B） and the effective barrier height（Φeff B）. Those two parameters of Ti Schottky co.tacts on 4H–Si C were deduced from I–V measurements in the temperature range of 298 K–503 K. The increase in Schottky barrier（SB） height（ΦB） and decrease in the ideality factor（n） with an increase measurement temperature indicate the presence of an inhomogeneous SB. The degree of inhomogeneity of the Schottky barrier depends on the annealing temperature, and it is at its lowest for 500-°C thermal treatment. The degree of inhomogeneity of the SB co.ld reveal effects of thermal treatments on Schottky co.tacts in other aspects.

关键词： Schottky co.tact Si C inhomogeneity barrier

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Development of 8-inch Key Processes for Insulated-Gate Bipolar Transistor

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Engineering 2015年第3期1卷 361-366页

作者： Guoyou Liu Rongjun Ding Haihui Luo CRRC Zhuzhou Electric locomotive Institute co. Ltd.

Based on the co.struction of the 8-inch fabricat ion line, advanced process technology of 8-inch wafer, as well as the fourth-generation high-voltage double-diffused metal-oxide semico.ductor(DMOS+) insulated-gate bipolar transistor(IGBT) technology and the fifth-generation trench gate IGBT technology, have been developed, realizing a great-leap forward technological development for the manufacturing of high-voltage IGBT from 6-inch to 8-inch. The 1600 A/1.7 kV and 1500 A/3.3 kV IGBT modules have been successfully fabricated, qualified, and applied in rail transportation traction system.

关键词： insulated-gate bipolar transistor (IGBT) high power density trench gate 8-inch rail transportation

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Formal Analysis and Improvement on Ultralightweight Mutual Authentication Protoco.s of RFID

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Chinese Journal of Electronics 2019年第5期28卷 1025-1032页

作者： XIAO Meihua LI Wei ZHONG Xiaomei YANG Ke CHEN Jia School of Software East China Jiaotong University Product Development Center CRRC ZHUZHOU LOCOMOTIVE CO.LTD

Ultralightweight mutual authentication protoco.s(UMAP) of Radio frequency identification(RFID) systems have attracted much attention from researchers. Many studies reveal that most of UMAP suffer malicious attack. To improve security of UMAP,formal analysis is performed with Simple promela interpreter(SPIN). Two typical UMAPs, which are RCIA and RAPP, are selected as our case study. A protoco. abstract modeling method is presented to make UMAP can be formalized simply. Using SPIN, verification results show that RCIA and RAPP are both vulnerable against desynchronization attack. A Generalized model of UMAP(G-UMAP) and a general patching scheme are presented for resisting the attack. To validate the patching scheme,formal verification is then performed for the improved protoco.. SPIN verification shows that the improved RCIA and RAPP both gain higher security. The above proposed modeling method has great significance for similar UMAP analyzing, and the proposed patching scheme is proved to be practical and reliable.

关键词： UMAP RCIA RAPP Key synchronization patching scheme Model checking

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Passivity breakdown of 13Cr stainless steel under high chloride and co.2 environment

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International Journal of Minerals,Metallurgy and Materials 2019年第3期26卷 329-336页

作者： Hui-xin Li Da-peng Li Lei Zhang Ya-wen Wang Xiu-yun Wang Min-xu Lu Institute for Advanced Materials and Technology University of Science and Technology Beijing Safetech Research Institute (Beijing) co. Ltd. CRRC Beijing locomotive co. Ltd.

Herein, the effect of high chloride ion(Cl^-) co.centration on the co.rosion behavior and passive film breakdown of 13Cr martensitic stainless steel under co.2 environment was demonstrated. The Cl^- co.centration was varied from 30 to 150 g/L and cyclic potentiodynamic polarization was co.ducted to investigate the influence of the Cl^- co.centration on the co.rosion potential(E_(co.r)), passive breakdown potential(E_(pit)), and repassivation potential(E_(rep)). The results of the polarization curves revealed that 13Cr stainless steel is susceptible to pitting under high Cl^- co.centration. The passive breakdown potential and repassivation potential decreased with the increase of Cl-co.centration. The semico.ducting behavior of the passive film was investigated by Mott-Schottky analysis and the point defect model(PDM). It was observed that the iron cation vacancies and oxygen vacancies were co.tinuously generated by autocatalytic reactions and the higher Cl^- co.centration resulted in higher vacancies in the passive film. Once the excess vacancies co.densed at the metal/film interface, the passive film became locally detached from the metal, which led to the breakdown of the passive film.

关键词： 13Cr stainless steel electrochemical characterization pitting co.rosion high chloride co.centration passive film breakdown

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