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Free-form surface texture morphology modeling in five-axis ball-end milling considering effective cutting edge

Thin-Walled Structures 2025年 215卷

作者： Sipei Zhu Guoqiang Fu Yue Zheng Caijiang Lu Xi Wang Tao Wang Jianzhong Fu School of mechanical engineering Southwest Jiaotong University Chengdu 610031 China State Key Laboratory of High-performance Precision Manufacturing Dalian University of Technology Dalian 116024 China State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South University Changsha 410083 China Technology and Equipment of Rail Transit Operation and Maintenance Key Laboratory of Sichuan Province Chengdu 610031 China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University Hangzhou 310027 China

Free-form workpieces are widely used in aerospace, energy, transportation etc. The quality of machined surface morphology and the overall texture morphology have a non-negligible influence on the accuracy and performance of the workpiece. In this paper, free-form surface texture morphology digital model in five-axis ball-end milling is proposed. Firstly, the kinematics expression of the cutting edge point is established combining with the general mathematical model of ball-end mill to explore the texture formation mechanism. Then, a fast determination method of effective cutting edge is proposed based on the tool-workpiece engagement geometry. Secondly, the discretization of the workpiece and cutting tool path in the parameter domain of the free-form surface are proposed referring to Z-map discretization concept. Cutting edge micro-element calculation is proposed based on the approximate arc constrained by the workpiece discrete precision. The free-form surface texture morphology digital model of five-axis ball-end milling is established. Thirdly, the digital models of bowl-shaped free-form surface texture morphology under different tool posture angle are established and the simulation efficiency of the proposed modeling methodology is verified. Fourthly, the experimental validation is carried out. The digital model is verified by the texture morphology comparison between digital models and machined surfaces under different posture angle and different surface position. Finally, the effect of feed per tooth and tool radius on the surface texture morphology and texture classification under different tool posture angles are explored.

关键词： Cutting parameters Five-axis milling Free-form surface workpiece Texture morphology

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Microscopic Distribution of Quaternary Ammonium Salt Organic Modifiers in the Interlayer Space of Montmorillonite: Molecular Simulation Study

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Materials (Basel, Switzerland) 2025年第10期18卷 2338页

作者： Wenxi Yu Xijian Yi Jianwei Yan Juan Cheng Siyu Ou Qiong Xue School of Packaging Engineering Hunan University of Technology Zhuzhou 412007 China. State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong University Nanchang 330013 China. College of Packaging Engineering Jinan University Zhuhai 519070 China.

This study employs molecular dynamics simulations to construct designed unit cells of organic montmorillonite (OMMT) modified with four types of quaternary ammonium salts. The effects of modifier type and quantity on the basal spacing of montmorillonite (MMT) were analyzed. Molecular motion, morphology, interaction energy (), and hydrogen bonding interactions were investigated to elucidate the molecular-level mechanisms between modifiers and MMT. The results indicate that the organic modification of MMT proceeds in three distinct stages: the filled stage, saturated stage, and supersaturated stage. During the filled stage, the basal spacing remains largely unchanged while increases rapidly. In the saturated stage, the basal spacing expands as the growth rate of slows. In the supersaturated stage, the basal spacing continues to increase while stabilizes. The transition from the filled to saturated stage is governed by the van der Waals space occupied by the modifiers. Within the MMT interlayer, the modifiers adopt a bilayer morphology, with the nitrogen atom heads adhering to the MMT surfaces and the tails self-assembling. These findings provide theoretical insights into the basal spacing expansion and organic modification mechanisms of MMT, thereby facilitating improved material compatibility.

关键词： molecular dynamics simulation montmorillonite organic modification quaternary ammonium salts

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Enhanced Hardness-Toughness Balance Induced by Adaptive Adjustment of the Matrix Microstructure in in Situ Composites

SSRN

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SSRN 2022年

作者： Zhao, L.Z. Guan, Y.M. Zhao, M.J. Liu, D.J. Jiao, H.T. Yu, M. Zhang, Lai-Chang Tang, Y.C. Key Laboratory of Advanced Materials for Vehicles and Laser Additive Manufacturing of Nanchang city East China Jiaotong University Nanchang330013 China Key Laboratory of Vehicle and Equipment of Education Ministry East China Jiaotong University Nanchang330013 China State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong University Nanchang330013 China Nanchang Railway Tongda Industry and Trade Co. Ltd. Nanchang330026 China School of Engineering Edith Cowan University 270 Joondalup Drive Joondalup PerthWA6027 Australia

With the development of high-speed and heavy-haul railway transportation, the surface failure of turnout rails becomes increasingly severe due to insufficient high hardness and toughness combination. The in situ bainite steel matrix composites with WC primary reinforcement was fabricated by direct laser deposition(DLD) in this work. With the increased primary reinforcement content, the adaptive adjustment of the matrix microstructure was obtained. Furthermore, dependence of the adaptive adjustment of matrix on the combination of hardness and impact toughness of the composites was *** interaction of the primary composite powder irradiated by laser during the DLD leads to the significant change of the phase composition and morphology in reinforcement and matrix of composites at same time. With the increased WC primary reinforcement content, the microstructure of matrix is changed from the dominant sheaves of lath-like bainite and few island-like retained austenite into needle-like lower bainite and plenty of block-like retained austenite, the final reinforcement is changed from Fe3W3C into Fe3W3C and *** the increased primary reinforcement content, the microhardness of bainite steel matrix composites increases remarkably, the impact toughness of the bainite steel matrix composite decreases. However, compared with conventional metal matrix composites, the in situ bainite steel matrix composites manufactured by DLD possess a much better hardness-toughness balance, which can be attributed to the adaptive adjustment of the matrix microstructure with the increased volume fraction of primary *** work provides a new insight into getting new materials with good combination of hardness and toughness. © 2022, The Authors. All rights reserved.

关键词： Reinforcement

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Blind source extraction based on EMD and temporal correlation for rolling element bearing fault diagnosis

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Smart and Resilient Transportation 2021年第1期3卷 52-65页

作者： Xuejun Zhao Yong Qin Hailing Fu Limin Jia Xinning Zhang State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China Beijing Research Center of Urban Traffic Information Sensing and Service Technologies Beijing Jiaotong University Beijing China and National Engineering Laboratory for System Safety and Operation Assurance of Urban Rail Transit Guangzhou China Structural Integrity and Health Monitoring Group Department of Aeronautics Imperial College London UK London China Railway Rolling Stock Corporation Limited Beijing China

Purpose Fault diagnosis methods based on blind source separation (BSS) for rolling element bearings are necessary tools to prevent any unexpected accidents. In the field application, the actual signal acquisition is usually hindered by certain restrictions, such as the limited number of signal channels. The purpose of this study is to fulfill the weakness of the existed BSS method. Design/methodology/approach To deal with this problem, this paper proposes a blind source extraction (BSE) method for bearing fault diagnosis based on empirical mode decomposition (EMD) and temporal correlation. First, a single-channel undetermined BSS problem is transformed into a determined BSS problem using the EMD algorithm. Then, the desired fault signal is extracted from selected intrinsic mode functions with a multi-shift correlation method. Findings Experimental results prove the extracted fault signal can be easily identified through the envelope spectrum. The application of the proposed method is validated using simulated signals and rolling element bearing signals of the train axle. Originality/value This paper proposes an underdetermined BSE method based on the EMD and the temporal correlation method for rolling element bearings. A simulated signal and two bearing fault signal from the train rolling element bearings show that the proposed method can well extract the bearing fault signal. Note that the proposed method can extract the periodic fault signal for bearing fault diagnosis. Thus, it should be helpful in the diagnosis of other rotating machinery, such as gears or blades.

关键词： Fault diagnosis Blind source extraction Signal decomposition Temporal correlation

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A Semi-Distribution Congestion Control Algorithm for Event-Driven M2M Communications

A Semi-Distribution Congestion Control Algorithm for Event-D...

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IEEE Conference on Vehicular Technology (VTC)

作者： Liu Yang Heng Liu Pingzhi Fan Li Hao Cong Ouyang State Key Laboratory of Rail Transit Engineering Informatization(FSDI) Xian P.R.China Communication and Sensor Network for Modern Transportation International Cooperation Center(CSNMT) Southwest Jiaotong University Chengdu Sichuan P.R.China

ISBN: (数字)9781728152073

ISBN: (纸本)9781728140537

Machine-to-Machine (M2M) communication is now playing a market-changing role in a wide range of business world. However, in event-driven M2M communications, a large number of devices activate within a short period of time, which in turn causes high radio congestion and severe access delay. In this paper, a semi-distribution congestion control algorithm (CCA) for event-driven M2M communications in LTE-Advanced networks is presented. This CCA uses the random access preamble idleness rate in a small number of slots to estimate the channel load. The eNodeB broadcasts the estimated value of traffic, so the M2M devices can calculate the control factor to control the flow. It is shown that, the throughput and delay performance of the proposed semi-distribution congestion control algorithm are significantly improved compared with the existing schemes.

关键词： Machine-to-machine communications Microsoft Windows Performance evaluation Task analysis Delays Throughput Transportation

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Reordering and Driving Strategy to Resolve Train Conflict Based on Cooperative Game Theory

Reordering and Driving Strategy to Resolve Train Conflict Ba...

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International Conference on Intelligent Transportation

作者： Zheng Qiao Tao Tang Lei Yuan National Engineering Laboratory for Urban Rail Transit Communication and Operation Control Beijing Jiaotong University Beijing China State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China

ISBN: (数字)9781728141497

ISBN: (纸本)9781728141503

According to vehicle-centralized train control design, instead of traditional interlocking equipment's unified management of rail resources, train can control resources based on plan autonomously, which asks for the capability of trains to detect and resolve the potential requisition conflict caused by multi-train decentralized control. This paper proposes a realtime autonomous conflict detection and resolution (rtACDR) model based on cooperative game theory. Firstly, the occupancy time of trains at sections is predicted by using blocking time theory, a criterion for the existence of conflict is also described. When potential conflict is detected, factors considered during dispatching and driving are weighted and described as an individual characteristic function, which represents relevant train's gaming revenue. At last, based on the Shapely theory, train's reordering at conflict area is transformed into the optimization problem of cooperative alliance's revenue, and solved by corresponding driving strategy's generation. The computational tests are performed on rail network of Cao Qiao Station in Beijing with various perturbations. Based on the detailed analysis of trains' driving strategies generated by model and the comparison of model and traditional dispatching strategy's performances, feasibility of proposed model is estimated preliminarily.

关键词： Games rails Game theory rail transportation Optimization Computational modeling Acceleration

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Micromechanical study of soil conditioning on Sandy Stratum for an EPB Shield

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Journal of Physics: Conference Series 2021年第1期2021卷

作者： Yanjie Ding State key Laboratory of Rail Transit Engineering Informatization China Railway First Survey and Design Institute Group Co. Ltd Xi'an 710043 China

In the construction technology of an earth pressure balance (EPB) shield, soil conditioning is an important technology. It is possible to condition the properties of excavation soil and improve the excavation efficiency by injecting suitable conditioners. Soil conditioning is more important in cohesionless stratum because the flow plasticity of this stratum is typically poor. The soil is conditioned by the interaction between the soil particles and the soil conditioners, the internal principles of which need to be investigated by microscopic tests. Based on the CT test, the changes in porosity after soil conditioning were analyzed, and it was revealed that soil conditioners can make pores form separate structures. Based on the SEM test, the mechanism for the reduction in porosity of the soil was obtained: the flakes formed by the conditioners replaced the original pores.

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Experimental Study on Mechanical Properties of Soft Clay under Different Stress Paths

Experimental Study on Mechanical Properties of Soft Clay und...

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2020 International Conference on New Energy and Sustainable Development, NESD 2020

作者： Lu, Yuan Ke, Wenhui Huang, Xiangguo Xiao, Mingzhao Chen, Bin Huang, Juehao Chen, Jian State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan430071 China University of Chinese Academy of Sciences Beijing100049 China Hubei Key Laboratory of Geo-Environmental Engineering Wuhan430071 China Soft Soil Research Center in Ningbo University of Technology State Key Laboratory of Geomechanics and Geotechnical Engineering Ningbo315211 China Wuhan Municipal Construction Group Co. Ltd Wuhan HUBEI430023 China Ningbo Rail Transit Group Co. Ltd. Ningbo315040 China

In actual engineering, when the soil element is subjected to load, the stress state will change accordingly. In this paper, undrained triaxial stress path tests for Ningbo reshaped saturated soft clay under different confining pressures are carried out. The test uses the GDS bidirectional vibrating triaxial instrument. The stress path dependence of saturated soft clay is studied. The stress-strain relationship and undrained shear strength under different stress path conditions are mainly analyzed. The test results show that the stress-strain relationship of the stress path test is obviously non-linear, basically strain hardening. The stress-strain curves of saturated remolded soft clay under different stress paths and consolidation pressures can be expressed in hyperbolic form. The initial stiffness E0 basically increases with the increase of the deflection angle of the stress path. The test results have certain reference significance for foundation pit and tunnel engineering. © Published under licence by IOP Publishing Ltd.

关键词： Stress-strain curves

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Turnout Health Assessment Based on Dynamic Time Warping 4th

Turnout Health Assessment Based on Dynamic Time Warping

引用

4th International Conference on Electrical and Information Technologies for rail Transportation, EITRT 2019

作者： Wang, Ning Wang, Hong Guang Jia, Limin Wang, Zhipeng Zhang, Huiyue State Key Lab of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China National Engineering Laboratory for System Safety and Operation Assurance of Urban Rail Transit Beijing Jiaotong University Guangdong China Beijing Research Center of Urban Traffic Information Sensing and Service Technologies Beijing Jiaotong University Beijing China Operation Headquarters Guangzhou Metro Group Guangdong China

ISBN: (纸本)9789811528651

Turnouts are vital components in the rail system. Assessing the healthy state of turnout and ensuring normal operation is essential. However, the faults of rolling element bearings under running occur suddenly. Thus, it is essential to develop a practicable and real-time method to put forward the assess the turnouts’ running state, which could insure the normal operation. This paper presents a novel method based on the dynamic time warping (DTW) to assess the running status. DTW have two superiorities: (1) DTW could calculate the distance between the different state by using calculating the total cost (minimum distance) of two time series, it makes DTW algorithm fast and simply, so the state is assessed timely. (2) The total cost not only be used to diagnose the fault of turnout, but also could be used to transfer to CV (confident values) to assess the state of the turnout. Hence, this method uses DTW to calculate the distance between the different turnout’s states and CV to assess the healthy state by using the distance. Finally, this method is verified by using the power data collected from Guangzhou Metro turnout testbed and Line 4. The result shows that it is accurate for turnout health assessment and suitable for practical scenarios. © Springer Nature Singapore Pte Ltd. 2020.

关键词： Roller bearings

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Autonomous routing research based on vehicle-centralized train control system

Autonomous routing research based on vehicle-centralized tra...

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International Conference on Intelligent Transportation

作者： Zheng Qiao Tao Tang Lei Yuan National Engineering Laboratory for Urban Rail Transit Communication and Operation Control Beijing Jiaotong University Beijing China Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China

ISBN: (数字)9781728141497

ISBN: (纸本)9781728141503

In vehicle-centralized train control design, the routing function is transferred from interlocking equipment to vehicle, which asks for the ability of train to schedule feasible route autonomously. This paper describes an autonomous routing schedule (ARS) model based on graph theory. Firstly, by converting key elements of rail network into directed graph nodes and marking the weights of arcs based on section transit time's prediction, a topological graph model reflecting railway structure's characteristic is set up. According to the graph model, a heuristic algorithm is used to search the feasible route with shortest transit time. Considering the limitation of rail state's information gathered by trains in decentralized control design, arc's weight (the prediction of transit time in rail section) is updated in real time based on the communication between trains so that the routing schedule can be dynamically adjusted based on section's availability. The computational tests are performed on Beijing Daxing Airport Station. The result shows the feasibility of model in searching route with reasonable transit time. It's potential for rerouting based on disturbances and resolve delays is also analyzed.

关键词： Routing rail transportation rails Prediction algorithms Schedules Heuristic algorithms Computational modeling

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