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Damage Evolution of Ballastless Track Concrete Exposed to Flexural Fatigue Loads:The Application of Ultrasonic Pulse Velocity,Impact-echo and Surface Electrical Resistance Method

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 353-363页

作者：杨志强李化建 WEN Jiaxing DONG Haoliang HUANG Fali WANG Zhen YI Zhonglai railway Engineering Research Institute China Academy of Railway Science Corporation LimitedBeijing 100081China State Key Laboratory for Track System of High-Speed railway Beijing 100081China School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China

In order to clarify the fatigue damage evolution of concrete exposed to flexural fatigue loads,ultrasonic pulse velocity(UPV),impact-echo technology and surface electrical resistance(SR) method were *** variable based on the change of velocity of ultrasonic pulse(Du) and impact elastic wave(Di)were defined according to the classical damage *** influences of stress level,loading frequency and concrete strength on damage variable were *** experimental results show that Du and Di both present a three-stages trend for concrete exposed to fatigue *** impact elastic wave is more sensitive to the microstructure damage in stage Ⅲ,the critical damage variable,i e,the damage variable before the final fracture of concrete of Di is slightly higher than that of ***,the evolution of SR of concrete exposed to fatigue loads were analyzed and the relationship between SR and Du,SR and Di of concrete exposed to fatigue loads were *** is found that the SR of concrete was decreased with the increasing fatigue cycles,indicating that surface electrical resistance method can also be applied to describe the damage of ballastless track concrete exposed to fatigue loads.

关键词： ballastless track fatigue damage ultrasonic pulse velocity impact-echo surface electrical resistance

Study on the subgrade deformation under high-speed train loading and water–soil interaction

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Acta Mechanica Sinica 2016年第2期32卷 233-243页

作者： Jian Han Guo-Tang Zhao Xiao-Zhen Sheng Xue-Song Jin State Key Laboratory of Traction Power Southwest Jiaotong University Chengdu 610031 China china railway corporation Beijing 100844 China

It is important to study the subgrade characteristics of high-speed railways in consideration of the water–soil coupling dynamic problem,especially when high-speed trains operate in rainy *** study develops a nonlinear water–soil interaction dynamic model of slab track coupling with subgrade under high-speed train loading based on vehicle–track coupling *** using this model,the basic dynamic characteristics,including water–soil interaction and without water induced by the high-speed train loading,are *** main factors-the permeability coefficien and the porosity-influencin the subgrade deformation are *** developed model can characterize the soil dynamic behaviour more realistically,especially when considering the influenc of water-rich soil.

关键词： Water–soil interaction High-speed train loading Finite difference method Subgrade deformation Permeability coefficien Porosity

An Experimental Study on Constraint Cooling Process of Hot-rolled CoilS

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Journal of Materials Science & Technology 2003年第Z1期19卷 220-222页

作者： Lijuan WANG Chunli ZHANG State Key Laboratory of rolling and Automation Northeastern University Shenyang 110004 China Shanghai Baosteel Group Corporation Shanghai 201900 China

In order to master mechanical property, surface quality and microstructure of constraint cooling (CC) coils undervarious water cooling parameters, more than 100 coils cooling experiments were done with real production process,of which is designed a cooling experimental instrument in the end. The experiments show that high initial coolingtemperature, discontinuous cooling style, and long cooling time can improve mechanical property of cooling coilsand shorten cooling time. The CC coils experiments cover the different steel grades, so that CC process effects onhot-rolled coils may be predicted and controlled actively.

关键词： Constraint cooling, Hot-rolled coils, Experiment

Resilience based importance measure analysis for SoS

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Journal of Systems Engineering and Electronics 2019年第5期30卷 920-930页

作者： PAN Xing WANG Huixiong YANG Yanjing ZHANG Guozhong School of Reliability and Systems Engineering Beihang UniversityBeijing 100191China china railway Signal and Communication corporation Beijing 100070China Institute of Systems Engineering China State Shipbuilding CorporationBeijing 100036China

In a system of systems(SoS),resilience is an important factor in maintaining the functionality,stability,and enhancing the operation *** the perspective of resilience,this paper studies the importance of the SoS,and a resilience-based importance measure analysis is conducted to provide suggestions in the design and optimization of the structure of the *** this paper,the components of the SoS are simplified as four kinds of network nodes:sensor,decision point,influencer,and *** this networked SoS,the number of operation loops is used as the performance indicator,and an approximate algorithm,which is based on eigenvalue of the adjacency matrix,is proposed to calculate the number of operation *** order to understand the performance change of the SoS during the attack and defense process in the operations,an integral resilience model is proposed to depict the resilience of the *** different perspectives of enhancing the resilience,different measures,parameters and the corresponding algorithms for the resilience importance of components are ***,a case study on an SoS is conducted to verify the validity of the network modelling and the resiliencebased importance analysis method.

关键词： system of systems (SoS) resilience network modelling importance measure analysis operation loop

Weldability of 1000 MPa Grade Ultra-low Carbon Bainitic Steel

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Journal of Iron and Steel Research International 2016年第7期23卷 705-710页

作者： Qing-mei JIANG Xiao-qiang ZHANG Li-qing CHEN Pipeline Department of china Petroleum Pipeline Engineering corporation Langfang 065000 Hebei China State Key Laboratory of rolling and Automation Northeastern University Shenyang 110819 Liaoning China

Maximum hardness test in weld heat-affected zone（HAZ）,oblique Y-groove cracking test and mechanical property test of welding joint of 1 000 MPa grade ultra-low carbon bainitic steel were carried out,so as to research the weldability of the *** results show that the steel has lower cold cracking sensitivity,and preheating temperature of 100 ℃ can help completely eliminate cold cracks,generating good process *** increase of preheating temperature can reduce the hardening degree of heat-affected *** strength of welding joint decreases and hardness reduces when heat inputs increase,and excellent mechanical properties can be obtained when low welding heat inputs are *** lath bainites of different orientations combined with a few granular bainites that effectively split the original coarse austenite grains are the foundation of good properties.

关键词： ultra-low carbon bainitic steel weldability cold cracking microstructure mechanical property

Investigation of insulation layer dynamic characteristics for high-speed railway

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Research in Cold and Arid Regions 2015年第4期7卷 430-437页

作者： HongYe Yan GuoTang Zhao DeGou Cai QianLi Zhang JianPing Yao AiJun Cheng railway Engineering Research Institute China Academy of Railway Sciences china railway corporation

Dynamic performance of insulation is one of the key parameters during the insulation application for high-speed railway subgrade. This paper conducted laboratory and field tests for the materials and dynamic load, especially for thermal performance, elastic deformation, and accumulated deformation of insulation materials. Experiment results show that mechanical properties of insulation layer structure are stable, which satisfies the requirements of the high speed railway.

关键词： high-speed railway insulation materials dynamic load elastic deformation accumulated deformation

DOA and Subarray-Interval Estimation for Arbitrarily Distributed UAV Swarm System

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china Communications 2023年第4期20卷 102-117页

作者： Dian Fan Yue Zhu Jia You Zhe Wang Nan Zhong The china Academy of Information and Communications Technology Beijing 100191China The china Academy of railway Sciences corporation Limited Beijing 100081China

In this paper,DOA and subarray-interval estimation are considered and applied to arbitrarily distributed unmanned aerial vehicle(UAV)swarm system,in which multiple small UAVs containing uniform linear array(ULA)are divided by unknown intervals because of dynamic *** parameters are taken to indicate the steering vector,namely,the direction of arrivals(DOAs)of target users,the intervals of UAVs,and the orientation angles of *** orientation angles are first estimated with an auxiliary user and the DOAs are obtained through a search free rooting method,despite the intervals among the ***,the intervals among UAVs can also be calculated via exhaustive when the number of target users are no less than *** further develop a low-complex method to reduce the computational complexity during subarray-interval *** deterministic Cramér-Rao bound(CRB)of the DOA,orientation angle and subarray-interval can be inferred in a closed ***,numerical instances are cited to verify the research results.

关键词： distributed subarray DOA orientation angle subarray-interval CRB

Experimental and Numerical Investigation on the Aerodynamic Characteristics of High-Speed Pantographs with Supporting Beam Wind Deflectors

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Fluid Dynamics & Materials Processing 2024年第1期20卷 127-145页

作者： Shiyang Song Tongxin Han Postgraduate Department China Academy of Railway SciencesBeijing100081China Locomotive&Car Research Institute China Academy of Railway Sciences Corporation LimitedBeijing100081China

Aiming to mitigate the aerodynamic lift force imbalance between pantograph strips,which exacerbates wear and affects the current collection performance of the pantograph-catenary system,a study has been conducted to support the beam deflector optimization using a combination of experimental measurements and computational fluid dynamics(CFD)*** results demonstrate that the size,position,and installation orientation of the wind deflectors significantly influence the amount of force *** also indicate that the front strip deflectors should be installed downwards and the rear strip deflectors upwards,thereby forming a“π”***,the lift force compensation provided by the wind deflectors increases with the size of the *** wind compensation strategies,such as control circuits,are also discussed,putting emphasis on the pros and cons of various pantograph types and wind compensation approaches.

关键词： High-speed pantograph aerodynamic lift force supporting beam wind deflectors computational fluid dynamics(CFD)

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.

Compared 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 become the key technological challenge of high-speed trains and significantl affects the economy,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 conception 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 collecting system,wheel truck compartment,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