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Chinese Journal of Aeronautics 2024年第5期37卷 506-519页

作者： Jiwen SHEN Weijing KONG Zhengyang XU Yongbin ZENG Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The surface integrity of metal micro-hole structures produced by electrochemical discharge machining is unsatisfactory owing to the insufficient reaction area and strength of electrolysis action.A novel ultrahigh-speed Rotary Electrochemical Discharge Machining(R-ECDM)using non-water-based electrolyte is proposed to improve surface integrity by changing the breakdown medium of spark discharge and increasing the reaction area and strength of electrolysis.A mathematical model was developed to establish the relationship between rotational speed and forces acting on the bubble.Based on the magnitude of forces,controlling rotational speed changed the behavior and departure radius of bubbles on the cathode surface.High-speed photographs validate that,in the mathematical model,the number and departure radius of bubbles on the cathode surface gradually decrease with the increase of rotational speed.The experimental results show that the roughness(Ra)of the micro-hole sidewall decreases from 2.54μm to 0.20μm when the rotational speed increases from 500 r/min to 40000 r/min.The length loss and wear ratio of the cathode are only 9.75μm and 6.5%,respectively.Finally,the micro-holes array with recast-free and surface roughness of 0.20μm is fabricated,demonstrating that the proposed approach contributes to improving surface integrity of metal micro-holes.

关键词： Electrochemical discharge machining Micro-holes Recast layer Ultrahigh-speed rotary Bubbles force analysis Non-water-based solution

force analysis CONSIDERING MANUFACTURE ERROR OF PIN-HOLE-OUTPUT MECHANISM IN CYCLOID DRIVE

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Chinese Journal of Mechanical Engineering 2002年第2期15卷 142-144页

作者： Guan Tianmin Shi XiaochunDepartment of Mechanical Engineering, Dalian Railway Institute, Dalian 116028, China Department of Mechanical Engineering Dalian Railway Institute Dalian 116028

Based on the analysis of the pin-hole-output mechanism in the cycloid drive,a more accurate force analysis method is provided, in which the manufacture error is considered, bywhich the contact force between pin and pi... 详细信息

关键词： Cycloid drive Pin-hole-output mechanism force analysis

Ion and electron motions in the outer electron diffusion region of collisionless magnetic reconnection

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Earth and Planetary Physics 2024年第3期8卷 472-478页

作者： Cong Chang QuanMing Lu San Lu Kai Huang RongSheng Wang Deep Space Exploration Laboratory School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China Chinese Academy of Sciences(CAS)Center for Excellence in Comparative Planetology CAS Key Laboratory of Geospace EnvironmentHefei 230026China Collaborative Innovation Center of Astronautical Science and Technology Harbin 150001China

Two-dimensional particle-in-cell simulations are performed to study the coupling between ion and electron motions in collisionless magnetic reconnection.The electron diffusion region(EDR),where the electron motions are demagnetized,is found to have a two-layer structure:an inner EDR near the reconnection site and an outer EDR that is elongated to nearly 10 ion inertial lengths in the outflow direction.In the inner EDR,the speed of the electron outflow increases when the electrons move away from the X line.In the outer EDR,the speed of the electron outflow first increases and then decreases until the electrons reach the boundary of the outer EDR.In the boundary of the outer EDR,the magnetic field piles up and forms a depolarization front.From the perspective of the fluid,a force analysis on the formation of electron and ion outflows has also been investigated.Around the X line,the electrons are accelerated by the reconnection electric field in the out-of-plane direction.When the electrons move away from the X line,we find that the Lorentz force converts the direction of the accelerated electrons to the x direction,forming an electron outflow.Both electric field forces and electron gradient forces tend to drag the electron outflow.Ion acceleration along the x direction is caused by the Lorentz force,whereas the pressure gradient force tends to decelerate the ion outflow.Although these two terms are important,their effects on ions are almost offset.The Hall electric field force does positive work on ions and is not negligible.The ions are continuously accelerated,and the ion and electron outflow velocities are almost the same near the depolarization front.

关键词： collisionless magnetic reconnection electron diffusion region force analysis particle-in-cell simulation

Tooth Position and Deformation of Flexspline Assembled with Cam in Harmonic Drive Based on force analysis

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Chinese Journal of Mechanical Engineering 2021年第6期34卷 385-404页

作者： Yunpeng Yao Xiaoxia Chen Jingzhong Xing Liteng Shi Yuqi Wang School of Mechanical Engineering Tiangong UniversityTianjin300387China Tianjin City Key Lab of Modern Mechatronics Equipment Technology Tianjin300387China

Deformation of the flexspline is the basis of analyzing tooth trajectory and designing tooth profile.Considering the tooth influence on the position of equivalent neutral layer,a piecewise method for calculating the deformation of flexspline assembled with a cam wave generator is presented in this paper.Firstly,a mechanic model of a ring of uniform thickness in contact with a rigid cam is established.The displacements of the ring inside and outside an unknown wrapping angle are determined by the geometric constraints of the cam profile and the equilibrium rela-tionship,respectively.Meanwhile,the wrapping angle is solved according to the boundary conditions.The assembly forces are derived to investigate the circumferential elongation and strain.Then,considering the tooth effects on the neutral layer of flexspline,the tooth is positioned on the equivalent neutral layer,which is the non-elongation layer within one gear pitch but offset from the geometric mid-layer.The equivalent neutral layer is positioned by the empirical formula of the offset ratio,which is summarized by the orthogonal simulation on finite element models of racks.Finally,finite element models of a ring-shaped and a cup-shaped flexspline assembled with elliptical cam are established to verify the effectiveness and accuracy of the piecewise method.The results show that,compared with the geometric method,the tooth positioning deviation calculated by the piecewise method can be reduced by about 70%with a more accurate deformation description from the geometric condition and mechanic condition inside and outside the wrapping angle.

关键词： Harmonic drive Deformation calculation Cam wave generator force analysis Equivalent neutral layer

Superconducting multipole wiggler with large magnetic gap for HEPS-TF

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Nuclear Science and Techniques 2022年第2期33卷 21-29页

作者： Xian-Jing Sun Fu-San Chen Xiang-Chen Yang Wan Chen Xiao-Juan Bian Min-Xian Li Rui Ge Miao-Fu Xu Yao Gao Jin-Can Wang Hui-Hua Lu Jian-She Cao Zhi-Qiang Li Zhuo Zhang Rui Ye Xiang-Zhen Zhang Shuai Li Bao-Gui Yin Mei Yang Ling-Ling Gong Da-Heng Ji Lin Bian Ran Liang Ya-Jun Sun Hong Shi Institute of High Energy Physics Chinese Academy of SciencesBeijing 10049China Key Laboratory of Particle Acceleration Physics and Technology Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China China Spallation Neutron Source Institute of High Energy PhysicsChinese Academy of SciencesDongguan 523803China

A 16-pole superconducting multipole wiggler with a large gap of 68 mm was designed and fabricated to serve as a multipole wiggler for HEPS-TF.The wiggler consists of 16 pairs of NbTi superconducting coils with a period length of 170 mm,and its maximum peak field is 2.6 Tesla.In magnet design,magnet poles were optimized.Furthermore,the Lorentz force on the coils and electromagnetic force between the upper and lower halves were computed and analyzed along with the stored energy and inductance at different currents.To enhance the critical current of the magnet coil,all the pole coils selected for the magnet exhibited excellent performance,and appropriate prestress derived from the coil force analysis was applied to the pole coils during magnet assembly.The entire magnet structure was immersed in 4.2-K liquid helium in the cryostat cooled solely by four two-stage cryocoolers,and the performance test of the superconducting wiggler was appropriately completed.Based on the measured results,the first and second field integrals on the axis of the superconducting wiggler were significantly improved at different field levels after the compensation of the corrector coils.Subsequently,the wiggler was successfully installed in the storage ring of BEPCII operation with beams.

关键词： Superconducting multipole wiggler force analysis Quench protection Magnetic field measurement HEPS-TF Cryostat

Flow regimes of the immiscible liquids within a rectangular microchannel

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Acta Mechanica Sinica 2021年第10期37卷 1544-1556,I0003页

作者： Xiang Wang Yan Pang Yilin Ma Yanlin Ren Zhaomiao Liu College of Mechanical Engineering and Applied Electronics Technology Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing100124China Beijing Key Laboratory of Advanced Manufacturing Technology Beijing University of TechnologyBeijing100124China

Flow regimes of two immiscible liquids at the cross junction within a rectangular microchannel are experimentally investigated.Characteristics of the flow regimes including critical conditions and interfacial deformations are presented.It is found that the occurrence of the tubing regime is favored by increased viscosity of the dispersed phase or reduced cross-sectional aspect ratio,leading to the shrinkage of the flow rate range that could produce droplets.In order to reveal the physical mechanism,the force analysis is carried out based on the tunnel structure formed between the interface and channel side walls within the rectangular cross-section.The reshaping stage and pinch-off stage are mainly driven by the interfacial tension,leading to far larger neck thinning rate compared to the superficial velocity of either phase.The filling stage and squeezing stage are dominated by the pressure drop across the dispersed tip while the role of the shear force becomes more important with increasing tunnel width.The filling period is estimated as t2≈kHwn02/Qd with k=1.34 and the squeezing period is expressed as t3/Tc=0.3Cac−1.According to the force analysis,the critical tip velocity under dripping scales with three key parameters,which can be expressed as(utip/U)*~QcLtip/wtunnel3.

关键词： Cross junction Flow regime Liquid interface force analysis Rectangular microchannel

Design and Control Scheme of the Mooring System

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Journal of Contemporary Educational Research 2022年第5期6卷 108-114页

作者： Jing Cong Basic Department of Liaoning Institute of Science and Technology Benxi 117000Liaoning ProvinceChina

In this paper,by analyzing the design and control scheme of the mooring system based on theoretical mechanics,force analysis is conducted on the buoy,steel pipe,steel drum,and anchor chain,and a reasonable mathematical model is constructed to solve the problems of the inclination angle of the steel drum and each section of the steel pipe,the shape of the anchor chain,the draft of the buoy,and the swimming area under different wind speeds,thus providing a reliable basis for the design of the system.

关键词： Mooring system Static balance force analysis Catenary

Stress Computation of Roadheader Shovel's by using the Finite Element Method

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International Journal of Plant Engineering and Management 2016年第2期21卷 107-114页

作者： LI Qiang ZHANG Ming-yu School of Mechanical and Electronic Engineering Suzhou University

Shovel board is an important component of the roadheader. Shovel board participate in complex and changeable tunneling work, and always under high load. In this paper, research the working condition of shovel board and analyze the shovel board by Inventor, and reach the stress and strain distribution in the shovel board bear the maximum force when working. Have some guiding on improving the shovel board structure design.

关键词： shovel board force analysis inventor finite element analysis

Numerical Simulation and analysis of Excavation and Support in Traffic Tunnel of a Power Station

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施工技术（中英文） 2021年第24期50卷 147-151页

作者： ZHOU Weibo LEI Ming WANG Tao SARHOSIS Vasilis Powerchina Northwest Engineering Co. Ltd.Xi’anShaanxi 710065China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhanHubei 430072China School of Civil Engineering University of LeedsLeeds LS29JTU.K.

To evaluate the rationality of the excavation and support structure design in tunnel engineering, numerical simulation and structural deformation stability analysis in excavation and support in a traffic tunnel are carried out in combination with the practical geological conditions study. The computation results demonstrate that following excavation, the surrounding rock deforms minimally and has a large self-bearing capacity. The shotcrete-bolt structure in the initial support has small deformation and stress, ensuring that it meets the safety and stability requirements. The stress of the secondary lining structure is calculated, which can also meet the structural strength requirements. The traffic tunnel’s supporting system is a practical and cost-effective manner. The proposed study will provide a specific reference for the design and research of the support structures in traffic tunnels.

关键词： undeground engineering traffic tunnel supports deformation force analysis