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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 3-11页

作者： Qiang Wei Z.Q.Zhu Yan Jia Jianghua Feng Shuying Guo Yifeng Li Shouzhi Feng Department of Electronic and Electrical Engineering The University of SheffieldSheffield S13JDU.K. IEEE the crrc zhuzhou institute Company Ltd. Zhuzhou 412001China

In this paper,the electromagnetic performance of variable flux memory(VFM)machines with series-magnetic-circuit is investigated and compared for different rotor *** on a V-type VFM machine,five topologies with different interior permanent magnet(IPM)arrangements are evolved and optimized under same *** on two-dimensional(2-D)finite element(FE)method,their electromagnetic performance at magnetization and demagnetization states is *** reveals that the iron bridge and rotor lamination region between constant PM(CPM)and variable PM(VPM)play an important role in torque density and flux regulation(FR)***,the global efficiency can be improved in VFM machines by adjusting magnetization state(MS)under different operating conditions.

关键词： Memory machine Permanent magnet Rotor topologies Series magnetic circuit Variable flux

Robust,self-adhesive,and low-contact impedance polyvinyl alcohol/polyacrylamide dual-network hydrogel semidry electrode for biopotential signal acquisition

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SmartMat 2024年第2期5卷 67-82页

作者： Guangli Li Ying Liu Yuwei Chen Yonghui Xia Xiaoman Qi Xuan Wan Yuan Jin Jun Liu Quanguo He Kanghua Li Jianxin Tang Hunan Key Laboratory of Biomedical Nanomaterials and Devices College of Life Sciences and ChemistryHunan University of TechnologyZhuzhouChina Department of Neurology Zhuzhou People's HospitalZhuzhouChina zhuzhou institute for Food and Drug Control ZhuzhouChina

Herein,we fabricated a flexible semidry electrode with excellent mechanical performance,satisfactory self-adhesiveness,and low-contact impedance using physical/chemical crosslinked polyvinyl alcohol/polyacrylamide dual-network hydrogels(PVA/PAM DNHs)as an efficient saline *** resultant PVA/PAM DNHs showed admirable adhesive and compliance to the hairy scalp,facilitating the establishment of a robust electrode/skin interface for biopotential signal ***,the PVA/PAM DNHs steadily released trace saline onto the scalp to achieve the minimized potential drift(1.47±0.39 mV/min)and low electrode–scalp impedance(18.2±8.9 kΩ@10 Hz).More importantly,the application feasibility of real-world brain−computer interfaces(BCIs)was preliminarily validated by 10 participants using two classic BCI *** mean temporal cross-correlation coefficients between the semidry and wet electrodes in the eyes open/closed and the N200 speller paradigms are 0.919±0.054 and 0.912±0.050,*** electrodes demonstrate anticipated neuroelectrophysiological responses with similar *** semidry electrode could also effectively capture robust P-QRS-T peaks during electrocardiogram *** their outstanding advantages of fast setup,user-friendliness,and robust signals,the proposed PVA/PAM DNH-based electrode is a promising alternative to wet electrodes in biopotential signal acquisition.

关键词： brain-computer interface dual-network hydrogel electrocardiogram signals electroencephalography signals semidry electrode

A novel multi-state bogie system reliability evaluation approach by extended d-MC model for high-speed trains

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Transportation Safety and Environment 2024年第3期6卷 35-46页

作者： Yong Fu Ruoqu Liu Jisheng Dai Wenlong Zhu Xin Liu Yong Qin zhuzhou crrc Times Electric Co. Ltd.Times RoadShifeng DistrictZhuzhouHunan 412001China Department of Statistics University of WarwickCoventry CV47ALUnited Kingdom State Key Lab of Rail Traffic Control&Safety Beijing Jiaotong UniversityHaidian DistrictBeijing 100044China

Bogie is a pivotal system and plays a critical part in the safety and reliability management of high-speed ***,the available bogie system reliability analysis methods lack the consideration of multi-state characteristics,and the common multi-state reliability analysis methods,being an NP-hard problem,lead to low *** order to overcome these drawbacks,this paper proposes a novel multi-state rail train bogie system reliability analysis approach based on the extended d-MC *** different function interactions within the bogie system are considered to build the multi-state bogie system flow network ***,an extended d-MC model is established to remove unnecessary d-MC candidates and duplicates,which greatly enhances the computing *** bogie system reliability is calculated,and examples are *** experiments are carried out for the different operational conditions of the bogie system and are used to test the practicability of the method proposed in this article;it is found that this method outperforms a newly developed method in solving multi-state reliability problems.

关键词： multi-state system reliability bogie flow network extended d-MC model

Remaining useful life prediction for train bearing based on an ILSTM network with adaptive hyperparameter optimization

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Transportation Safety and Environment 2024年第2期6卷 75-86页

作者： Deqiang He Jingren Yan Zhenzhen Jin Xueyan Zou Sheng Shan Zaiyu Xiang Jian Miao State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Guangxi Key Laboratory of Manufacturing System&Advanced Manufacturing Tec hnologySc hool of Mec hanical EngineeringGuangxi Univ ersityNanning 530004GuangxiChina zhuzhou crrc Times Electric Co. Ltd.Zhuzhou 412001HunanChina

Remaining useful life(RUL)prediction for bearing is a significant part of the maintenance of urban rail transit *** RUL is closely linked to the reliability and safety of train running,but the current prediction accuracy makes it difficult to meet the re-quirements of high reliability *** at the problem,a prediction model based on an improved long short-term memory(ILSTM)network is ***,the variational mode decomposition is used to process the signal,the intrinsic mode function with stronger representation ability is determined according to energy entropy and the degradation feature data is constructed com-bined with the time domain ***,to improve learning ability,a rectified linear unit(ReLU)is applied to activate a fully connected layer lying after the long short-term memory(LSTM)network,and the hidden state outputs of the layer are weighted by attention *** Harris Hawks optimization algorithm is introduced to adaptively set the hyperparameters to improve the performance of the ***,the ILSTM is applied to predict bearing *** experimental cases,the better perfor-mance in bearing RUL prediction and the effectiveness of each improving measures of the model are validated,and its superiority of hyperparameters setting is demonstrated.

关键词： train bearing remaining useful life prediction long short-term memory(LSTM) attention mechanism Harris Hawks op-timization(HHO)

Multi-scale Modeling and Finite Element Analyses of Thermal Conductivity of 3D C/SiC Composites Fabricating by Flexible-Oriented Woven Process

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 275-288页

作者： Zheng Sun Zhongde Shan Hao Huang Dong Wang Wang Wang Jiale Liu Chenchen Tan Chaozhong Chen Nanjing University of Aeronautics and Astronautics Nanjing 210016China School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China crrc institute Corporation Limited Beijing 100070China

Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale proposed in this work are used to simulate the thermal conductivity behaviors of the 3D C/SiC *** entirely new process is introduced to weave the preform with three-dimensional orthogonal *** 3D steady-state analysis step is created for assessing the thermal conductivity behaviors of the composites by applying periodic temperature boundary *** RVE models of cuboid,hexagonal and fiber random distribution are respectively developed to comparatively study the influence of fiber package pattern on the thermal conductivities at the ***,the effect of void morphology on the thermal conductivity of the matrix is analyzed by the void/matrix *** prediction results at the mesoscale correspond closely to the experimental *** effect of the porosities and fiber volume fractions on the thermal conductivities is also taken into *** multi-scale models mentioned in this paper can be used to predict the thermal conductivity behaviors of other composites with complex structures.

关键词： 3D C/SiC composites Finite element analyses Multi-scale modeling Thermal conductivity

Improvement of Film Cooling Design for Turbine Vane Leading Edge Considering Combustor Outflow

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Journal of Thermal Science 2024年第1期33卷 311-327页

作者： WANG Xinyu LIU Cunliang FU Zhongyi LI Yang ZHU Huiren School of Power and Energy Northwestern Polytechnical UniversityXi'an 710072China AECC Hunan Aviation Powerplant Research institute Zhuzhou 412002China

As the interaction between the combustor and the turbine in the aero-engine continues to increase,the film cooling design considering the combustor swirling outflow has become the research *** swirling inflow and high-temperature gas first affect the vane leading edge(LE).However,no practical improved solution for the LE cooling design has been proposed considering the combustor swirling *** this paper,the improved scheme of showerhead cooling is carried out around the two ways of adopting the laid-back-fan-shaped hole and reducing the coolant outflow *** film cooling effectiveness(η) and the coolant flow state are obtained by PSP(pressure-sensitive-paint) and numerical simulation methods,*** research results show that the swirling inflow increases the film distribution inhomogeneity by imposing the radial pressure gradient on the vane to make the film excessively gather in some *** showerhead film cooling adopts the laid-back-fan-shaped hole to reduce the momentum when the coolant flows *** this cooling scheme improves the film attachment and increases the surface-averaged film cooling effectiveness(η_(sur)) by as much as15.4%,the film distribution inhomogeneity *** reducing the coolant outlet angle,the wall-tangential velocity of the coolant increases,and the wall-normal velocity *** the swirl intake condition,both ηand the film distribution uniformity are significantly increased,and the growth of η_(sur) is up to 16.5%.This paper investigates two improved schemes to improve the showerhead cooling under the swirl intake condition to provide a reference for the vane cooling design.

关键词： turbine vane showerhead cooling swirling inflow laid-back-fan-shaped hole film hole inclination

Hovering rotor aerodynamics in extreme ground effect

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Chinese Journal of Aeronautics 2024年第7期37卷 204-219页

作者： Zhenlong WU Tianyu ZHANG Huijun TAN Haoyu ZHOU Wei CHEN Maixiang XIE College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China China Aviation Power Machinery Research institute Zhuzhou 412002China

This paper presents an experimental and numerical study of the aerodynamics of a moderate-scale rotor hovering in the Extreme Ground Effect(EGE)where rotor height-offground is below half the rotor *** tip vortex field was visualized by using the PIV *** aerodynamic performance,tip vortex trajectory,wall jet characteristics,surface pressure and velocity fields were measured and *** explore more deeply the flow mechanisms of the extreme ground effect,Detached Eddy Simulation(DES)was conducted on completely structured *** results showed significant deviations of the rotor performance in EGE from that in Regular Ground Effect(RGE)with the rotor heights of more than half the rotor ***,the flow structures of the rotor in EGE are considerably complex,such as the wall jet and groundwash flow *** rotor wake flow and tip vortices impact the ground more frequently,resulting in distinctive characteristics of the surface pressure and velocity fields in EGE.

关键词： Rotor Ground effect Tip vortex Detached Eddy Simulation(DES) Groundwash

Fatigue research of metro car body based on operational loads

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Railway Sciences 2024年第5期3卷 558-574页

作者： Xihong Jin Feng Guo State Key Laboratory of Heavy-Duty and Express High-Power Electric Locomotive Product Research and Development CenterCRRC Zhuzhou Locomotive Co.Ltd.ZhuzhouChina

Purpose–The principle of infinite life design currently directs fatigue resistance strategies for metro car ***,this principle might not fully account for the dynamic influence of operational loads and the inevitable presence of *** study aims to integrate methods of service life estimation and residual life assessment,which are based on operational loads,into the existing infinite life verification framework to further ensure the operational safety of subway ***/methodology/approach–Operational loads and fatigue loading spectra were determined through the field *** material test was conducted to investigate characteristics of the fracture toughness and the crack growth *** fatigue strength of the metro car body was first verified using the finite element method and Moore–Kommers–Japer *** service life was then estimated by applying the Miner rule and high-cycle fatigue curves in a modified form of the Basquin ***,the residual life was assessed utilizing a fracture assessment diagram and a fitted curve of crack growth rate adhered to the Paris ***–Neither the maximum utilization factor nor the cumulative damage exceeds the threshold value of 1.0,the metro car body could meet the design life requirement of 30 years or 6.6 million ***,three out of five fatigue key points were significantly influenced by the operational loads,which indicates that a single fatigue strength verification cannot achieve the infinite life design objective of the metro car *** a projected design life of 30 years,the tolerance depth is 12.2 mm,which can underscore a relatively robust damage tolerance ***/value–The influence of operational loads on fatigue life was presented by the discrepancy analysis between fatigue strength verification results and service life estimation *** fracture properties of butt-welded joints were tested and used for the damage tolerance *** d

关键词： Metro car body Field test Structural integrity Damage accumulation Damage tolerance

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 *** 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 *** is essential to systematically investigate the control approaches to restrain pathogens from transmitting in passenger ***,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 *** these bases,numerical investigations on the motion of pathogen-laden droplets were conducted,and decontamination techniques were examined ***,control measures on the pathogen transmission and pathogen decontamination schemes were ***,highly efficient decontamination devices were developed,and coping strategies for epidemic emergencies were *** 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

Turbo-shaft engine adaptive neural network control based on nonlinear state space equation

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Chinese Journal of Aeronautics 2024年第4期37卷 493-507页

作者： Ziyu GU Qiuhong LI Shuwei PANG Wenxiang ZHOU Jichang WU Chenyang ZHANG Jiangsu Province Key Laboratory of Aerospace Power System Nanjing University of Aeronautics and AstronauticsNanjing 210016China AECC Hunan Aviation Powerplant Research institute Zhuzhou 412002China

Intelligent Adaptive Control(AC) has remarkable advantages in the control system design of aero-engine which has strong nonlinearity and uncertainty. Inspired by the Nonlinear Autoregressive Moving Average(NARMA)-L2 adaptive control, a novel Nonlinear State Space Equation(NSSE) based Adaptive neural network Control(NSSE-AC) method is proposed for the turbo-shaft engine control system design. The proposed NSSE model is derived from a special neural network with an extra layer, and the rotor speed of the gas turbine is taken as the main state variable which makes the NSSE model be able to capture the system dynamic better than the NARMA-L2 model. A hybrid Recursive Least-Square and Levenberg-Marquardt(RLS-LM) algorithm is advanced to perform the online learning of the neural network, which further enhances both the accuracy of the NSSE model and the performance of the adaptive controller. The feedback correction is also utilized in the NSSE-AC system to eliminate the steady-state tracking error. Simulation results show that, compared with the NARMA-L2 model, the NSSE model of the turboshaft engine is more accurate. The maximum modeling error is decreased from 5.92% to 0.97%when the LM algorithm is introduced to optimize the neural network parameters. The NSSE-AC method can not only achieve a better main control loop performance than the traditional controller but also limit all the constraint parameters efficiently with quick and accurate switching responses even if component degradation exists. Thus, the effectiveness of the NSSE-AC method is validated.

关键词： Adaptive control systems Turbo-shaft engine Neural network Nonlinear state space equation NARMA-L2