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Electromagnetic characteristic analysis and design of a linear motor used for ultra-high-speed EMS maglev train

Science China Technological Sciences 2024年第6期67卷 1957-1973页

作者： GAO Han SHI TingNa GAO XinMai LEI YanXiao YAN Dong GUO LiYan YAN Yan college of Electrical Engineering Zhejiang University Zhejiang University Advanced Electrical Equipment Innovation Center State Key Laboratory of High-speed Maglev Transportation Technology crrc qingdao sifang co.ltd.

The operating speed of the commercial electromagnetic suspension(EMS) maglev train has been over 430 km/h, making it the fastest means of land transportation. With the increasing demands of people traveling, it is necessary to further improve the operating speed of maglev trains. Aiming to examine whether the existing EMS system can meet the requirements of ultra-highspeed operation(more than 600 km/h), the electromagnetic characteristics of an EMS linear motor under the operating speed of 600–1000 km/h fed by a square-wave voltage supply is investigated in this article. First, an electromagnetic field model of the EMS system under the square-wave voltage supply is established to investigate its electromagnetic performance, e.g., the characteristics of phase current, the magnetic flux density, and the electromagnetic force. Second, the relationship between the harmonic components of the air-gap magnetic flux density and electromagnetic force is investigated using the two-dimensional fast Fourier transform(2D-FFT) to reveal the mechanism of electromagnetic force ripple. Third, to address the issues of excessive armature current density and significant electromagnetic force ripple, the linear motor is re-designed by enlarging the stator slot area and reshaping the mover's main magnetic poles. Furthermore, the Taguchi method is used to further improve the electromagnetic characteristics of the linear electric motor. Finally, the effectiveness of the proposed optimal design is validated by the finite-element analysis(FEA) based co-simulation.

关键词： ultra-high-speed maglev transportation electromagnetic suspension (EMS) linear motor electromagnetic force ripple suppression

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The influence of the leading-edge angle of subgrade on the aerodynamic loads of a high-speed train in a wind tunnel

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Transportation Safety and Environment 2024年第2期6卷 45-54页

作者： Zeyun Yang Gang Xu Fan Wu Lei Zhang Jian Du Dmitri Vainchtein Key Labor atory of Traffic Safety on Track Ministry of EducationSchool of Traffic&Transportation EngineeringCentral South UniversityChangsha 410075HunanChina crrc Academy(qingdao)co. Ltd.Qingdao 266111ShandongChina crrc qingdao sifang co. Ltd.Qingdao 266111ShandongChina Nyheim Plasma Institute Drexel UniversityCamden 08103USA

The purpose of this study is to establish the correlation between the boundary layer over the subgrade and the aerodynamic loads act-ing on the train model in conventional wind tunnel tests.Firstly,flow characteristics around the subgrade with different leading-edge angles(15°,30°and 45°)are investigated through the particle image velocimetry(PIV)experimental test method.Then,wind tunnel tests of the aerodynamic performance of a high-speed train are carried out.The results are compared with previous experimental data obtained by moving model tests.Results show that,due to the presence of a boundary layer,the pressure acting on the lower part of the train head decreases,while other locations are not significantly affected.This is the reason for the reduction of the aerodynamic drag and lift on the train.In addition,the reduction effects become more obvious when the thickness of the boundary layer increases.The experimental results obtained could serve as a calibration of aerodynamic forces for wind tunnel tests on high-speed trains.

关键词： high-speed train ground effect aerodynamic performance wind tunnel test PIV experiment

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Research and development of prevention and control measures on the transmission of pathogens in compartments of passenger transport

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Transportation Safety and Environment 2024年第1期6卷 1-7页

作者： Hongqi Tian Tiantian Wang Lei Xu Miao Sha Shujun Chen Zeyun Yang Yan Zhu Dawei Chen Hengkui Li Lei Zhang Bosen Qian Xudong Tian Key Laboratory of Traffic Safety on Track of Ministry of Education School of Traffic&Transportation EngineeringCentral South UniversityChangshaHunan 410075China crrc qingdao sifang co. Ltd.QingdaoShandong 266111China crrc Changchun Railway Vehicles co. Ltd.ChangchunJilin 130062China crrc Tangshan co. Ltd.TangshanHebei 064000China crrc Industrial Research Institute(qingdao)co. Ltd.QingdaoShandong 266109China

contagious pathogens like coVID-19 transmitted via respiratory droplets spread effortlessly in the passenger compartments of transport,significantly jeopardizing passengers’safety when taking public transportation.To date,studies on the fundamental theories of airborne droplet transmission and the engineering application of decontamination techniques are insufficient for the prevention and control of pathogens transmitting in the compartments of passenger transport.It is essential to systematically investigate the control approaches to restrain pathogens from transmitting in passenger compartments.Herein,a theoretical framework for calculating the transmission of pathogens in a complex compartment environment was proposed,and experimental platforms that satisfy the Biosafety Level-2 Laboratory safety level for compartment environment simulations were built based on a set of real train cabins.On these bases,numerical investigations on the motion of pathogen-laden droplets were conducted,and decontamination techniques were examined experimentally.Thereby,control measures on the pathogen transmission and pathogen decontamination schemes were proposed.Moreover,highly efficient decontamination devices were developed,and coping strategies for epidemic emergencies were devised.The outcomes provide theoretical and technical support for developing the next generation of transportation and the prevention and control measures cooperatively considering regular and pandemic times.

关键词： contagious pathogen airborne transmission passenger compartment of transport decontamination technique

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智慧城轨车地一体化机电系统标准体系构建研究

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China Standardization 2024年第1期125卷 56-59页

作者：杨廷志 crrc qingdao sifang co. Ltd.

With the rapid development and application of emerging information technologies such as cloud computing,big data,artificial intelligence,5G,satellite communication,and blockchain in urban rail transit,China’s urban rail transit has entered an era of intelligent transformation and upgrading.The development of intelligent systems and the construction of smart urban rail transit have formed a consensus in the industry.The electromechanical system is an important component of urban rail transit engineering,covering power supply stations,vehicles,stations,and lines.The depot and control center are important support for promoting the development of urban rail transit towards informatization and intelligence.However,research on the technical standards for the smart urban rail vehicle-ground integrated electromechanical system has just begun,and a technical standards system has not yet been formed,which cannot better support the electromechanical system.Therefore,it is necessary to conduct research on the technical standards system,propose the common criteria structure and standards list of the standards system,which can provide reference and guidance for the planning and establishment of China’s smart urban rail standards system.

关键词： smart urban rail vehicles vehicle-ground integration electromechanical system standards system standards list

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Pyrolysis Empirical Modeling of Polyester Glass Fiber Reinforced Plastics Using Sestak-Berggren Model Method

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Journal of Thermal Science 2024年第2期33卷 725-738页

作者： NAN Wei JI Wenhui YUAN Yanping YUAN Zhongyuan SUN Yong School of Mechanical Engineering Southwest Jiaotong UniversityChengdu610031China crrc Changchun Railway Vehicles co. LtdChangchun130062China

Polyester Glass Fiber Reinforced Plastic(Polyester GFRP),a thermosetting plastic comprised of glass fiber and polyester polymer compounds,is extensively utilized in high-speed trains.Unraveling its pyrolysis mechanism is crucial as it significantly influences the combustion characteristics and fire safety aspects.Currently,kinetic research on polyester GFRP primarily focuses on employing the coats-Redfern method to derive a theoretical kinetic model.However,the pyrolysis process of polyester GFRP is complex and the aforementioned theoretical model fails to accurately describe the pyrolysis mechanism.Therefore,this study seeks to utilize the Sestak and Berggren(SB) model as a methodological approach to reveal the complex reaction mechanism during the pyrolysis process.Based on thermogravimetric analysis,the entire pyrolysis process of polyester GFRP is divided into two primary stages.Furthermore,model-free methods are employed to ascertain the activation energy and pre-exponential factor.The results show that the fitted empirical models of the two main pyrolysis stages are f(α)=(1-α)^(1.47)[-ln(1-α)]^(1.50) and f(α)=(1-α)^(1.77)[-ln(1-α)]^(1.72),respectively.The predicted results are in good agreement with experimental data under different heating rates,which indicates that the empirical model can sufficiently describe the pyrolysis process of polyester GFRP.

关键词： polyester GFRP model-fitting methods empirical models pyrolysis

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Resilient performance of self-centering hybrid rocking walls with curved interface under pseudo-static loading

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Earthquake Engineering and Engineering Vibration 2024年第1期23卷 65-85页

作者： Su Xing Yan Shi Sun Xianglei Wang Tao School of Civil Engineering Shenyang Jianzhu UniversityShenyang 110168China PetroChina East China Design Institute co. Ltd.Qingdao 266000China qingdao country Garden Bolin Real Estate co. Ltd.Qingdao 266100China

Frame and rocking wall(FRW)structures have excellent resilient performance during earthquakes.However,the concrete at interfacial corners of rocking walls(RWs)is easily crushed due to local extreme compression during the rocking process.An innovative RW with a curved interface is proposed to prevent interfacial corners from producing local damage,enhancing its earthquake resilient performance(ERP).The precast wall panel with a curved interface is assembled into an integral self-centering hybrid rocking wall(SCRW)by two post-tensioned unbonded prestressed tendons.Moreover,two ordinary energy dissipation steel rebars and two shear reinforcements are arranged to increase the energy dissipation capacity and lateral resistance.Two SCRW specimens and one monolithic reinforced concrete(RC)shear wall(SW)were tested under pseudo-static loading to compare the ERPs of the proposed SCRW and the SW,focusing on studying the effect of the curved interface on the SCRW.The key resilient performance of rocking effects,failure modes,and hysteretic properties of the SCRW were explored.The results show that nonlinear deformations of the SCRW are concentrated along the interface between the SCRW and the foundation,avoiding damage within the SCRW.The restoring force provided by the prestressed tendons can effectively realize self-centering capacity with small residual deformation,and the resilient performance of the SCRW is better than that of monolithic SW.In addition,the curved interface of the SCRW makes the rocking center change and move inward,partially relieving the stress concentration and crush of concrete.The rocking range of the rocking center is about 41.4%of the width of the SCRW.

关键词： self-centering hybrid rocking wall(SCRW) monolithic shear wall(SW) earthquake resilient performance(ERP) curved interface rocking center

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A 16-bit 18-MSPS flash-assisted SAR ADC with hybrid synchronous and asynchronous control logic

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Journal of Semiconductors 2024年第6期45卷 3-12页

作者： Junyao Ji Xinao Ji Ziyu Zhou Zhichao Dai Xuhui Chen Jie Zhang Zheng Jiang Hong Zhang School of Microelectronics Xi'an Jiaotong UniversityXi'an 710049China qingdao Hi-image Tech.co.ltd. Qingdao 266100China

This paper presents a 16-bit,18-MSPS(million samples per second)flash-assisted successive-approximation-register(SAR)analog-to-digital converter(ADC)utilizing hybrid synchronous and asynchronous(HYSAS)timing control logic based on an on-chip delay-locked loop(DLL).The HYSAS scheme can provide a longer settling time for the capacitive digital-to-analog converter(CDAC)than the synchronous and asynchronous SAR ADC.Therefore,the issue of incomplete settling or ringing in the DAC voltage for cases of either on-chip or off-chip reference voltage can be solved to a large extent.In addition,the fore-ground calibration of the CDAC’s mismatch is performed with a finite-impulse-response bandpass filter(FIR-BPF)based least-mean-square(LMS)algorithm in an off-chip FPGA(field programmable gate array).Fabricated in 40-nm CMOS process,the proto-type ADC achieves 94.02-dB spurious-free dynamic range(SFDR),and 75.98-dB signal-to-noise-and-distortion ratio(SNDR)for a 2.88-MHz input under 18-MSPS sampling rate.

关键词： SAR ADC control logic reference ringing DAC incomplete settling

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Influence of carbides and pores on the localized deformation of nickel-based single-crystal superalloys

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Progress in Natural Science:Materials International 2024年第3期34卷 562-568页

作者： Rengeng Li Yu Zhang Haoyi Niu Hao Wang Hao Wu Key Laboratory for Light-weight Materials Nanjing Tech University college of Materials Science and Engineering Chongqing University crrc Qishuyan Institute co.ltd.

The carbides and pores play a critical role in the cracking tendencies of nickel-based single-crystal superalloys during deformation. In the present study, the deformation mechanism and local strain evolution behavior around carbides and pores were studied through in-situ tensile deformation experiments. The findings indicate that multiple slip systems are easily activated during tensile deformation in single-crystal alloys. Furthermore, the strain localization in carbides is influenced by their morphology, with rod-like and flake-like carbides demonstrating an increased likelihood of cracking during deformation. The strain localization adjacent to pores is markedly more intense, rendering these areas particularly susceptible to cracking. Our work therefore offers a theoretical foundation for enhancing the mechanical properties of nickel-based single-crystal superalloys by controlling carbide morphology and pore formation.

关键词： Carbides In-situ tensile Nickel-based single-crystal Pores Strain evolution

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On the electric behaviour of conductive grease inside the contact zone

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Friction 2024年第4期12卷 683-697页

作者： Yuxin ZHOU Jinjie LIU Xinming LI He CHONG Bo HAN Qinghua BAI SKF(Shanghai)Automotive Technologies co. Ltd.Shanghai 201814China School of Mechanical and Automotive Engineering Qingdao University of TechnologyQingdao 266250China

conductive grease has been considered as a potential solution in addressing electric erosion issue inside motor bearings.Understanding the conductive grease performance,especially the electric and tribological behaviour is crucial for its application.This paper combines bulk grease characterization and contact film study considering both electrical and tribological loading conditions.The results show that the electric performance for the selected conductive grease sample is electric field dependent,including both frequency and voltage amplitude.Its film impedance inside the contact area is closely related to the external electric field,running condition,and lubrication regime.The following film impedance calculation tells that not only bulk grease electric parameters,but the contact parameter,lubricant film contour and lubrication condition should be considered when performing the overall bearing electrical modelling.

关键词： Electric erosion lubricant conductivity grease film impedance

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Fault Diagnosis Method of Rolling Bearing Based on ESGMD-CC and AFSA-ELM

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Structural Durability & Health Monitoring 2024年第1期18卷 37-54页

作者： Jiajie He Fuzheng Liu Xiangyi Geng Xifeng Liang Faye Zhang Mingshun Jiang School of Traffic&Transportation Engineering Central South UniversityChangsha410075China Project Management Department CRRC Advanced Composites Co.Ltd.Qingdao266108China School of control Science and Engineering Shandong UniversityJinan250061China

Incomplete fault signal characteristics and ease of noise contamination are issues with the current rolling bearing early fault diagnostic methods,making it challenging to ensure the fault diagnosis accuracy and reliability.A novel approach integrating enhanced Symplectic geometry mode decomposition with cosine difference limitation and calculus operator(ESGMD-CC)and artificial fish swarm algorithm(AFSA)optimized extreme learning machine(ELM)is proposed in this paper to enhance the extraction capability of fault features and thus improve the accuracy of fault diagnosis.Firstly,SGMD decomposes the raw vibration signal into multiple Symplectic geometry components(SGCs).Secondly,the iterations are reset by the cosine difference limitation to effectively separate the redundant components from the representative components.Additionally,the calculus operator is performed to strengthen weak fault features and make them easier to extract,and the singular value decomposition(SVD)weighted by power spectrum entropy(PSE)can be utilized as the sample feature representation.Finally,AFSA iteratively optimized ELM is adopted as the optimized classifier for fault identification.The superior performance of the proposed method has been validated by various experiments.

关键词： Symplectic geometry mode decomposition calculus operator cosine difference limitation fault diagnosis AFSAELM model

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