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Stage identification and process optimization for fast drilling EDM of film cooling holes using KBSI method

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Advances in Manufacturing 2023年第3期11卷 477-491页

作者： Jian wang Xue-Cheng Xi Ya-Ou Zhang Fu-Chun zhao wan-sheng zhao State Key Laboratory of Mechanical System and Vibration Shanghai 200240People's Republic of China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240People's Republic of China

Fast drilling electrical discharge machining(EDM)is widely used in the manufacture of film cooling holes of turbine ***,due to the various hole orientations and severe electrode wear,it is relatively intricate to accurately and timely identify the critical moments such as breakout,hole completion in the drilling process,and adjust the machining strategy *** breakout detection and hole completion determination methods are not suitable for the high-efficiency and fully automatic production of film cooling holes,for they almost all depend on preset thresholds or training data and become less appropriate when machining condition *** the breakout and hole completion detection problems can be abstracted to an online stage identification problem,in this paper,a kurtosis-based stage identification(KBSI)method,which uses a novel normalized kurtosis to denote the recent changing trends of gap voltage signals,is developed for online stage *** identification accuracy and generalization ability of the KBSI method have been verified in various machining *** improve the overall machining efficiency,the influence of servo control parameters on machining efficiency of each machining stage was analyzed experimentally,and a new stage-wise adaptive control strategy was then proposed to dynamically adjust the servo control parameters according to the online identification *** performance of the new strategy is evaluated by drilling film cooling holes at different hole *** results show that with the new control strategy,machining efficiency and the machining quality can be significantly improved.

关键词： Fast drilling electrical discharge machining(EDM) Film cooling holes Breakout detection Hole completion determination Stage identification Process optimization

Electrical arc contour cutting based on a compound arc breaking mechanism

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Advances in Manufacturing 2022年第4期10卷 583-595页

作者： Guo-Jian He Lin Gu Ying-Mou Zhu Ji-Peng Chen wan-sheng zhao K.P.Rajurkar State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240People’s Republic of China School of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing210037People’s Republic of China Center for Nontraditional Manufacturing Research University of Nebraska-LincolnLincolnNEUSA

Electrical arc contour cutting(EACC)is a novel high-efficiency material cutting process that applies arc plasma to perform efficient and economical contour cutting of difficult-to-cut *** to conventional electrical arc machining(EAM),this process can remove the allowance of open structures and plates in bulk mode,rather than entirely in the form of *** with existing contour cutting methods,EACC possesses the advantages of high cutting efficiency and a deep cutting ***,a compound arc breaking mechanism(CABM),which integrates hydrodynamic force and mechanical motion,has been applied to control the discharge arc column in EACC,while also strengthening the debris expelling effect in the narrow discharge *** CABM implementation conditions were studied,based on arc column distortion images captured by a high-speed camera and simulation results of the flow field and debris distribution.A set of machining experiments was designed and conducted to optimize the performance of the proposed ***,a SiC_(p)/Al metal matrix composite(MMC)space station workpiece was machined to verify the feasibility and efficiency of this process.

关键词： Electrical arc contour cutting(EACC) Electrical arc machining(EAM) Compound arc breaking mechanism(CABM) SiC_(p)/Al metal matrix composite(MMC) High efficiency

Modified constitutive models for Inconel 718 considering current density and temperature in electrically assisted forming process

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Chinese Journal of Aeronautics 2024年第2期37卷 524-540页

作者： Xuan CUI Rui zhao Min wan School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Jiangxi Research Institute of Beihang University Jiangxi 330000China

Electrically Assisted Forming(EAF)technology has obvious advantages in material *** develop an effective constitutive model considering electrical effects,room temperature and electrically assisted quasi-static uniaxial tensile tests were conducted using ultrathin nickelbased superalloy plates with a thickness of 0.25 *** research focused on the two most widely recognized effects:the Joule thermal and the electric athermal *** mechanism of current action can be divided into two scenarios:one considering the Joule thermal effect only,and the other considering both effects *** basic constitutive models,namely the Modified-Hollomon model and the Johnson-Cook(J-C)model,were selected to be optimized through the classification of two different situations,and four optimized constitutive models were *** was found that the J-C model with simultaneous consideration of the Joule thermal effect and electric athermal effect had the best prediction effect by comparing the results of these four ***,the accuracy of the optimization model was verified by finite element simulation of the electrically assisted stretching optimization *** results show that the constitutive model can effectively predict the temperature effect caused by the Joule heat effect and the athermal effect of current on the material.

关键词： Joule heating Elastoplasticity Plastic deformation Superalloys Constitutive models

Modeling of flow and debris ejection in blasting erosion arc machining in end milling mode

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Advances in Manufacturing 2020年第4期8卷 508-518页

作者： Ji-Peng Chen Lin Gu wan-sheng zhao Mario Guagliano School of Mechanical and Electronic Engineering Nanjing Forestry UniversityNanjing 210037People's Republic of China Department of Mechanical Engineering Polytechnic University of MilanPiazza Leonardo da Vinci32MilanItaly State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240People's Republic of China

Blasting erosion arc machining(BEAM)is a typical arc discharge machining technology that was developed around 2012 to improve the machinability of difficult-to-cut *** milling BEAM has been successfully developed and preliminarily applied in ***,owing to the high complexity of the flow field and the difficulty of observing debris in the discharge gap,studies of the flow and debris in end milling BEAM are *** this study,fluid dynamics simulations and particle tracking are used to investigate the flow characteristics and debris ejection processes in end milling ***,the end milling BEAM m o d e is *** the numerical modeling parameters,geometric models,and simulation methods are presented in ***,the flow distribution and debris ejection are described,analyzed,and *** velocity and pressure distributions of the axial feed and radial feed are observed;the rotation speed and milling depth are found to have almost no effect on the flow velocity ***,debris is ejected more rapidly in the radial feed than in the axial *** particle kinetic energy tends to increase with increasing milling depth,and smaller particles are more easily expelled from the flushing *** study attempts to reveal the flow field properties and debris ejection mechanism of end milling BEAM,which will be helpful in gaining a better understanding of BEAM.

关键词： Modeling Flow Debris ejection Blasting erosion arc machining(BEAM) End milling

Evaluating changes in business distribution within urban rail transit hubs in Beijing via Point of Interest (POI) data analysis (2008-2020)

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Frontiers of Architectural Research 2024年第2期13卷 305-318页

作者： Bo wan Dongyang wan Qiang sheng School of Architecture and Design Beijing Jiaotong UniversityBeijing 100044China

This paper,set against the backdrop of expanding urban rail networks and dynamic urban development,focuses on the distribution and evolution of commercial Points of Interests(POIs)within the central urban rail transit areas of *** study examines data from four different years-2008,2013,2017,and 2020-to observe the temporal evolution of commercial *** identifies stable explanatory variables affecting the distribution and evolution of commercial POIs,which include rail transit accessibility,characteristics of the working and residential population distribution around stations,and the construction intensity in the vicinity of station *** statistical analysis and model building,relatively stable linear regression equations were established,with R2 values generally maintained above 0.5(except for 2017).The study advances our understanding of the influence of rail transit on urban commercial spaces and how this influence shifts with temporal and urban developmental *** elucidates the correlation between changes in the number of businesses and spatial configuration,offering insights and information for urban planners and policy *** research also serves as a model for exploring the interplay between urban rail transit and commercial spaces in other major cities.

关键词： Urbanrail transit areas Spatial configuration Distributionand evolution of commercial POls

Upper-rim-modified thioether thiacalix[4]arene used for liquid-liquid extraction of Au(Ⅲ)and Pd(Ⅱ)in hydrochloric acid medium

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Chinese Journal of Chemical Engineering 2024年第2期66卷 110-118页

作者： sheng wan Rong Xie Jianhong Fan Kewen Tang Department of Chemistry and Chemical Engineering Hunan Institute of Science and TechnologyYueyang 414006China

Gold(Au)and palladium(Pd)play an increasing role in the production and human life;Therefore,it is of great significance to study their recovery.A 5,11,17,23-tetra-ethylthio-25,26,27,28-tetra-hydroxyl thiacalix[4]arene(TCAET)was synthesized specifically for the capture of Au(Ⅲ)and Pd(Ⅱ)from HCl medium by liquid-liquid *** a 0.1 mol·L^(-1)HCl medium,the transfer of Au(Ⅲ)and Pd(Ⅱ)from the aqueous phase to the organic phase was highly efficient,with a transfer ratio of 100%for Au(Ⅲ)and 98%for Pd(Ⅱ).Furthermore,the extraction equilibrium time for Au(Ⅲ)was just 5 ***'s method data demonstrated that TCAET formed complexes with Au(Ⅲ)and Pd(Ⅱ)in a ratio of 2:3 and 1:1,respectively,during the extraction *** showed high selectivity toward Pd(Ⅱ)and Au(Ⅲ)over other competing metal ***,both Au(Ⅲ)and Pd(Ⅱ)could be successfully stripped from the loaded organic phases with a 1.0 mol·L^(-1)thiourea in 0.5 mol·L^(-1)HCl and 0.5 mol·L^(-1)thiourea in 0.5 mol·L^(-1)HCl,*** obtained from five consecutive extraction-stripping cycles showed good reusability of TCAET toward Au(Ⅲ)and Pd(Ⅱ)*** conclusion can provide a certain reference for thiacalixarene in the recovery of precious metal species.

关键词： Thiacalixarene Upper-rim modification Liquid-liquid extraction Precious metal Thioether

Application of ultrasonic fatigue technology in very-high-cycle fatigue testing of aviation gas turbine engine blade materials:A review

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Science China(Technological Sciences) 2024年第5期67卷 1317-1363页

作者： zhao JiuCheng wan Jie ZHANG ShiZhong YAN ChuLiang zhao HongWei Key Laboratory of CNC Equipment Reliability Ministry of Education Jilin UniversityChangchun 130025China School of Mechanical&Aerospace Engineering Jilin UniversityChangchun 130025China Chongqing Research Institute of Jilin University Chongqing401120China School of Aeronautic Science and Engineering Beihang UniversityBeijing 102206China

The need for very-high-cycle fatigue(VHCF)testing up to 1010cycles of aviation gas turbine engine blade materials under combined mechanical loads and complex environments has encouraged the development of VHCF testing instrumentation and *** article begins with a comprehensive review of the existing available techniques that enable VHCF *** advances in ultrasonic fatigue testing(UFT)techniques are highlighted,containing their new capabilities and methods for single load,multiaxial load,variable amplitude fatigue,and combined cycle *** techniques for conducting UFT in high-temperature,humid environments,and corrosive environments are *** developments in mechanical loading and environmental building techniques provide the possibility of laboratory construction for real service conditions of blade *** techniques that can be used for in situ monitoring of VHCF damage are *** issues in the UFT field are presented,and countermeasures are ***,the existing problems and future trends in the field are briefly described.

关键词： aviation gas turbine engine blade materials ultrasonic fatigue very-high-cycle fatigue high-temperature complex stress in situ testing

Microstructure evolution and mechanical properties of brazing joint for ultra-thin-walled Inconel 718 considering grain size effect and brazing temperature

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Chinese Journal of Aeronautics 2024年第2期37卷 541-556页

作者： Rui zhao Yueshuai SONG Hui KANG Min wan School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Jiangxi Research Institute of Beihang University Jiangxi 330000China

The systematic investigation of the mechanical properties and microstructure evolution process of ultra-thin-walled Inconel 718 capillary brazing joints is of great significance because of the exceptionally high demands on its *** achieve this objective,this study investigates the impact of three distinct brazing temperatures and five typical grain sizes on the brazed joints’mechanical properties and microstructure evolution *** evolution analysis was conducted based on Electron Back Scatter Diffraction(EBSD),Scanning Electron Microscopy(SEM),X-Ray Diffraction(XRD),High-Resolution Transmission Electron Microscopy(HRTEM),and Focused Ion Beam(FIB).Besides,the mechanical properties and fracture behavior were studied based on the uniaxial tension tests and in-situ tension *** findings reveal that the brazing joint’s strength is higher for the fine-grain capillary than the coarse-grain one,primarily due to the formation of a dense branch structure composed of G-phase in the brazing *** effects of grain size,such as pinning and splitting,are amplified at higher brazing ***,micro-cracks initiate around brittle intermetallic compounds and propagate through the eutectic zone,leading to a cleavage fracture *** fracture stress of fine-grain specimens is higher than that of coarse-grain due to the complex micro-crack ***,this study contributes significantly to the literature by highlighting the crucial impact of grain size on the brazing properties of ultra-thin-walled Inconel 718 structures.

关键词： EYWORDS Ultra-thin-walled structure Brazing Inconel 718 Grain size effect Brazing temperature

An effective catalyst carrier SiO_(2):Enhancing catalytic and combustion properties of CuFe_(2)O_(4)on energetic components

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Defence Technology（防务技术） 2024年第2期32卷 383-392页

作者： Li Ding Chong wan Suhang Chen zhao Qin Kangzhen Xu School of Chemical Engineering/Xi'an Key Laboratory of Special Energy Materials Northwest UniversityXi'an710069China Xi’an Modern Chemistry Research Institute Xi'an710065China

To enhance the catalytic activity of copper ferrite(CuFe_(2)O_(4))nanoparticle and promote its application as combustion catalyst,a low-cost silicon dioxide(SiO_(2))carrier was employed to construct a novel CuFe_(2)O_(4)/SiO_(2)binary composites via solvothermal *** phase structure,morphology and catalytic activity of CuFe_(2)O_(4)/SiO_(2)composites were studied firstly,and thermal decomposition,combustion and safety performance of ammonium perchlorate(AP)and 1,3,5-trinitroperhydro-1,3,5-triazine(RDX)with it affecting were then systematically *** results show that CuFe_(2)O_(4)/SiO_(2)composite can remarkably either advance the decomposition peak temperature of AP and RDX,or reduce the apparent activation energy at their main decomposition ***,the flame propagation rate of RDX was promoted by about 2.73 times with SiO_(2)content of 3 wt%,and safety property of energetic component was also improved greatly,in which depressing the electrostatic discharge sensitivity of pure RDX by about 1.89 *** addition,the effective range of SiO_(2)carrier content in the binary catalyst is found to be 3 to 5 wt%.Therefore,SiO_(2)opens a new insight on the design of combustion catalyst carrier and will promote the application of CuFe_(2)O_(4)catalyst in solid propellant.

关键词： Copper ferrite Silicon dioxide Combustion catalyst Thermal decomposition Laser ignition