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Study on the improvement of semi-Hertzian wheel/rail contact algorithms

Journal of Traffic and Transportation Engineering(English Edition) 2025年第1期12卷 23-33页

作者： Yaru Liang Qunsheng Wang Jing Zeng Bin Zhu Rancheng Mao State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China Urban Rail Transit Center of CARS China Academy of Railway Sciences Corporation LimitedBejing 100081China

The normal stress distribution of the contact patch is the base for wheel/rail dynamic analysis as well as the wheel wear *** the wheel polygonalization appears on the worn-type wheel tread of the high-speed trains,the lateral and longitudinal relative wheel/rail curvature around the contact patch will vary with the change of wheel circumferential *** such a case,the commonly used Hertzian contact method cannot meet the calculation precision,while even the non-Hertzian method has relatively high precision,but its calculation efficiency cannot meet the demand of engineering application.A non-Hertzian method was introduced to analyze the influence of the wheel polygonalization on the contact *** studying the shape and the pressure distribution of the contact patches at different contact positions,it is found that when the wavelength of the wheel polygonalization is larger than 65 mm,the results of the improved semiHertzian method can agree well with the non-Hertzian method with reasonable computing ***,to ensure that the calculation result can meet the accuracy requirement when the wheelset yaw motion occurs,the trace method is used to improve the semi-Hertzian method and verified by the contact method.

关键词： High-speed railway Wheel polygonalization Wheelset yaw motion Contact algorithm Semi-Hertzian method

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Spatial confinement of free-standing graphene sponge enables excellent stability of conversion-type Fe_(2)O_(3)anode for sodium storage

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Chinese Chemical Letters 2025年第3期36卷 544-549页

作者： Jun Dong Senyuan Tan Sunbin Yang Yalong Jiang Ruxing Wang Jian Ao Zilun Chen Chaohai Zhang Qinyou An Xiaoxing Zhang Hubei Key Laboratory for High-efficiency Utilization of Solar Energy and Operation Control of Energy Storage System Hubei University of TechnologyWuhan 430068China State Key Laboratory of New Textile Materials and Advanced Processing Technologies Wuhan Textile UniversityWuhan 430200China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China Nanjing University of Aeronautics and Astronautics Nanjing 210016China

Conversion-type anode materials are highly desirable for Na-ion batteries(NIBs)due to their high theoretical ***,the active materials undergo severe expansion and pulverization during the sodiation,resulting in inferior cycling ***,a self-supporting three-dimensional(3D)graphene sponge decorated with Fe_(2)O_(3)nanocubes(rGO@Fe_(2)O_(3))is ***,the 3D graphene sponge with resilience and high porosity benefits to accommodate the volume expansion of the Fe_(2)O_(3)nanocubes and facilitates the rapid electrons/ions transport,enabling spatial confinement to achieve outstanding ***,the free-standing rGO@Fe_(2)O_(3)can be directly used as an electrode without additional binders and conductive additives,which helps to obtain a higher energy *** on the total mass of the rGO@Fe_(2)O_(3)material,the rGO@Fe_(2)O_(3)anode presents a specific capacity of 859 mAh/g at 0.1 A/*** also delivers an impressive cycling performance(327 mAh/g after 2000 cycles at 1 A/g)and a superior rate capacity(162mAh/g at 20 A/g).The coin-type Na_(3)V_(2)(PO_(4))_(3)@C//rGO@Fe_(2)O_(3)NIB exhibits an energy density of 265.3Wh/*** unique 3D ionic/electronic conductive network may provide new strategies to design advanced conversion-type anode materials for high-performance NIBs.

关键词： Conversion-type anode Spatial confinement Fe_(2)O_(3) Graphene network Self-supporting Sodium-ion batteries

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Mechanochemical control of graphene etching along zigzag and armchair edge directions

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Friction 2025年第4期13卷 97-104页

作者： Yilong Jiang Chuan Tang Chao Chen Yangqin Liu Yang Wang Seong H.Kim Junhui Sun Linmao Qian Lei Chen Tribology Research Institute The State Key Laboratory of Rail Vehicle SystemSchool of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China Department of Chemical Engineering and Materials Research Institute The Pennsylvania State UniversityUniversity ParkPennsylvania 16802USA State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China

The atomic edge structure of graphene governs its unique electronic properties with applications in nanoscale electronics and *** fully realize its potential,it is critical to develop a precision etching process producing graphene edges along desired ***,we present a novel approach utilizing scanning probe lithography(SPL)facilitated by a mechanochemical atomic attrition *** technique enables the fabrication of nanopatterns in single-layer graphene from graphene edges,precisely along the crystallographic orientation of zigzag(ZZ)and armchair(AC)edges,without inducing mechanical damage to the surrounding *** functional theory(DFT)calculations revealed that the dissociation of CC bonds by the SPL probe is mediated by the formation of interfacial bridge bonds between the graphene edge and the reactive silica *** SPL-based mechanochemical etching method enables the construction of various nanodevice structures with specific edge orientations,which allows the exploitation of their electronic properties.

关键词： atomic attrition fabrication zigzag(ZZ)and armchair(AC)edges graphene nanopatterns scanning probe lithography(SPL) density functional theory(DFT)calculation

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Monitoring Conductor Sags for Dynamic Line Rating Based on Induced Signals in Overhead Ground Wires

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IEEE Transactions on Power Delivery 2025年第3期40卷 1289-1297页

作者： Cui, Zherui Zhang, Bo Wang, Xiankang Yao, Yao Zhou, Xueming Tsinghua University Department of Electrical Engineering State Key Laboratory of Power System Operation and Control Beijing100084 China State Grid Hubei Electric Power Research Institue Wuhan430000 China

The sag information of conductors is important for dynamic line rating. This paper proposes a novel monitoring method for conductor sags based on the current or voltage in ground wires, which is produced by mutual inductance between conductors and ground wires. The devices of this method are easy to install and maintain, and the monitoring effect is not affected by bad weather such as snow and fog. To obtain sag information, a calculation method of induced signals in the ground wires is firstly proposed. Then the sensitivity of the induced signals in the ground wires to the variation of conductor sags is evaluated. The relationship between the induced signals in the ground wires and the sag information is established through neural network. A scaled test model of overhead transmission line is established to verify the proposed method. The accuracy of deduced results is acceptable. © 1986-2012 IEEE.

关键词： Wire

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Semi-Autonomous Navigation Based on Local Semantic Map for Mobile Robot

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Journal of Shanghai Jiaotong university(Science) 2025年第1期30卷 27-33页

作者： ZHAO Yanfei XIAO Peng WANG Jingchuan GUO Rui Department of Automation Institute of Medical RoboticsShanghai Jiao Tong UniversityShanghai200240China State Key Laboratory of System Control and Information Processing Ministry of Education of ChinaShanghai200240China Shanghai Engineering Research Center of Intelligent Control and Management Shanghai200240China State Grid Intelligence Technology Co. Ltd.Jinan250013China

Mobile robots represented by smart wheelchairs can assist elderly people with mobility *** paper proposes a multi-mode semi-autonomous navigation system based on a local semantic map for mobile robots,which can assist users to implement accurate navigation(e.g.,docking)in the environment without prior *** order to overcome the problem of repeated oscillations during the docking of traditional local path planning algorithms,this paper adopts a mode-switching method and uses feedback control to perform docking when approaching semantic *** last,comparative experiments were carried out in the real *** show that our method is superior in terms of safety,comfort and docking accuracy.

关键词： semi-autonomous navigation mobile robot semantic map voice interaction

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Optoelectronic-Coupled-Driven Microrobot for Biological Cargo Transport in Conductive Isosmotic Glucose Solution

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ACS Applied Materials and Interfaces 2025年第19期17卷 28425-28435页

作者： Zhuang, Rencheng Chang, Xiaocong Sha, Jinrui Yu, Zehao Shi, Enbo Lu, Minqiao Liu, Junmin Zhang, Guangyu Zhou, Dekai Li, Longqiu State Key Laboratory of Robotics and System Harbin Institute of Technology Heilongjiang Harbin150001 China Chongqing Research Institute Harbin Institute of Technology Chongqing400722 China Zhengzhou Research Institute Harbin Institute of Technology Zhengzhou450000 China School of Life Science and Technology Harbin Institute of Technology Heilongjiang Harbin150001 China

Electric field-driven micro/nanorobots, as micro/nanodevices with autonomous motion capability, have emerged as promising candidates for targeted cargo delivery in biomedical applications due to their advantages of label-free operation, selectivity, and controllability. In biological systems, many biological cargos need to be operated in conductive isosmotic solutions to ensure their viability. However, in the conductive solution, electric field-driven micro/nanorobots exhibit significantly reduced propulsion performance, despite retaining the capability to manipulate cargos by the dielectrophoretic force. This limitation restricts the wider applicability of electric field-driven micro/nanorobots in biomedical fields. This paper presents a novel optoelectronic-coupled-driven α-Fe2O3@aTiO2/Au microrobot, which exhibits significantly improved mobility and enables biological cargo transportation in the conductive isosmotic glucose solution. Benefiting from the flowerlike surface structure and composite photocatalytic material, the proposed microrobot exhibits enhanced photocatalytic capability, enabling efficient propulsion in glucose solution under light irradiation. In addition, the motion behavior of the microrobot under light, electric, and optoelectronic-coupled fields is investigated. It is found that the speed of the microrobot could exceed 300 μm/s under coupled fields, which is more than ten times faster than that of previously reported electric field-driven micro/nanorobots. Due to the magnetic property, the proposed microrobot can be precisely navigated under the guidance of an external uniform magnetic field. Furthermore, the proposed microrobot can achieve the transportation of various biological cargos in a conductive isosmotic glucose solution. The proposed microrobot opens a new avenue for targeted delivery and holds great potential for applications in the biological and pharmaceutical fields. © 2025 American Chemical Society.

关键词： Medical nanotechnology

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Parameter-Adaptive Feature Mode Decomposition Method for Compound Fault Feature Extraction in Rotating Machinery

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IEEE Sensors Journal 2025年第10期25卷 17491-17502页

作者： Xin, Junsheng Chen, Zaigang Chen, Xin Guo, Liang Southwest Jiaotong University State Key Laboratory of Rail Transit Vehicle System Chengdu610031 China Southwest Jiaotong University College of Mechanical Engineering Chengdu610031 China

Rotating machinery is a critical and easily damaged component in large-scale equipment. The coupling between the various components of the system often leads to compound failures, which can severely affect the safe operation of the equipment. Consequently, the prompt and accurate detection of fault information is essential for ensuring the safety and reliability of mechanical equipment. Recently proposed feature mode decomposition (FMD) tailored for mechanical fault feature extraction has received wide attention due to its superior filtering performance. However, the FMD is sensitive to input control parameters and the period estimation of the signal in this algorithm is also susceptible to noise interference, which will bring limitations to the practical compound fault diagnosis applications. To solve the above issues, a parameter-adaptive FMD (PAFMD) is proposed in this article. First, a spectral trend band division method is employed to initialize the finite impulse response (FIR) filter bank, enabling the adaptive acquisition of accurate filter coefficients. Then, a period estimation method based on an autocorrelation signal-to-noise ratio (ASNR) is proposed to determine the fault period accurately, thus iteratively guiding the filter to realize the accurate extraction of fault features. Finally, the decomposition modes containing fault information are automatically selected based on the period similarity of the fault signal, and a filter length selection strategy from coarse to fine is proposed to determine the optimal filter length to obtain the best fault feature modes. Both simulation and experimental validations demonstrate that the proposed PAFMD method can accurately and efficiently extract the multi-fault feature information with higher robustness and noise immunity. © 2001-2012 IEEE.

关键词： FIR filters

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Improving Reliability of Life Applications Using Model-Based Brain Switches via SSVEP

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IEEE Transactions on Biomedical Engineering 2025年第5期72卷 1636-1644页

作者： Meng, Jianjun Li, Songwei Li, Guangye Luo, Ruijie Sheng, Xinjun Zhu, Xiangyang Shanghai Jiao Tong University Department of Mechanical Engineering Shanghai China Shanghai Jiao Tong University State Key Laboratory of Mechanical System and Vibration Shanghai200240 China

The brain switch improves the reliability of asynchronous brain-computer interface (aBCI) systems by switching the control state of the BCI system. Traditional brain switch research focuses on extracting advanced electroencephalography (EEG) features. However, a low signal-to-noise ratio (SNR) of EEG signals resulted in limited feature information and low performance of brain switches. Here, we design a virtual physical system to build the brain switch, allowing users to trigger the system through periodic brainwave modulation, fully integrating limited feature information and improving reliability. Furthermore, we designed multiple experiments to validate the effectiveness of the proposed brain switch based on steady-state visual evoked potentials (SSVEP). The results verified the performance of SSVEP brain switches based on virtual physical systems, improving the reliability of brain switches to 0.1 FP-h or even better with acceptable triggering time and calibration-free for most subjects. This represents that the proposed virtual physical model-based brain switch can utilize SSVEP features and output the reliable commands required to control external devices, promoting BCI real applications. © 1964-2012 IEEE.

关键词： Brain computer interface

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Microscale mechanism of material removal process on burr defect formation in grinding superalloy honeycomb composites

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Journal of Manufacturing Processes 2025年 147卷 133-150页

作者： Wang, Haihang Wang, Chenguang Dang, Jiaqiang Guo, Guoqiang An, Qinglong Ming, Weiwei Chen, Ming State Key Laboratory of Mechanical System and Vibration School of Mechanical Engineering Shanghai Jiao Tong University Shanghai China Shanghai Spaceflight Precision Machinery Institute Shanghai China

Nickel-based superalloy honeycomb composite (NBSHC) is indispensable in the extreme fields such as missile, hypersonic vehicles and aeroengine due to the high temperature resistance and light weight. However, the NBSHC is difficult to be machined, and microscale mechanism of material removal process on burr of NBSHC is not clarified, resulting in burrs that are particularly to be formed during conventional processing and clamping methods. To solve these problems, the NBSHC was ground with ice fixation. The simulation models of grinding depth, speed and cutting angle (process parameters) were established considering the grinding path and ice freezing condition for the first time. Based on the simulations, the microscale material removal and process parameters action mechanisms of NBSHC grinding were comprehensively revealed by coupling stress, plastic strain and temperature fields. To verify the mechanisms and obtain the machined quality of NBSHC, the NBSHC grinding experiments were designed by the novel cutting angle analytical model and ice clamp. The results showed the material removal volume and plastic strain increased with the increment of grinding depth, leading to a subsequent increase in burrs. The increasing volume of material removal per time, decreasing force and fracture strength, and thermal softening effects induced by temperature factors dominated in sequence with the increment of grinding speed, resulting that the burr increased initially, decreased subsequently and ultimately increased as the grinding speed incrementally adjusted. Cutting angle affected burr size by influencing the fracture difficulty of burr and thermal softening effects, and the optimal cutting angle intervals were [0°, 30°] and [150°, 180°]. © 2025

关键词： Superalloys

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An equivalent modeling method for integrated water-wind-solar systems based on sparrow search algorithm

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Energy Informatics 2025年第1期8卷 1-16页

作者： Lu, Yuanhong Zhang, Jie Zhang, Jingyue Huang, Libin Guo, Haiping Hu, Binjiang Guo, Tianyu State Key Laboratory of HVDC Electric Power Research Institute China Southern Power Grid Guangzhou510663 China National Energy Power Grid Technology R & D Centre Guangzhou510663 China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System Guangzhou510663 China CSG Key Laboratory for Power System Simulation Electric Power Research Institute China Southern Power Grid Guangzhou510663 China

In the context of extensive integration of renewable energy sources into the electrical grid, the grid's fault transient behaviors have undergone significant changes. However, conventional single-unit equivalent models fail to accurately capture the fault transient responses of combined wind-solar-hydro power stations and often require substantial computational resources, leading to reduced simulation efficiency. This study proposes a cluster-based equivalent modeling approach for hybrid wind-solar-hydro power plants using the Sparrow Search Algorithm. key factors influencing fault characteristics, including the distance to the Point of Common Coupling, DC-side current-limiting measures, irradiance levels, water flow rates, wind speeds, and reactive power at the outlet, are identified and used to construct a transient model. Euclidean distances are computed for these factors, and initial clustering centers for wind turbines are determined using an improved max–min distance technique. These factors and clustering centers serve as the training dataset to establish the clustering equivalent model. Simulation results, conducted on the MATLAB2022 platform, demonstrate that the SSA-based model outperforms the single-unit equivalent model by over 150 times in terms of accuracy. Additionally, the SSA-based model achieves a delay time, defined as the time required to compute the system's transient response after a fault, of less than 5 ms, which is less than one-twentieth of the delay time of the single-unit equivalent model. These improvements highlight the model's ability to accurately capture dynamic power responses under various disturbances, making it highly suitable for real-time applications in hybrid renewable energy systems. © The Author(s) 2025.

关键词： MATLAB

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