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Wear Mechanism and Prediction Model of Polycrystalline Diamond Tool in Milling Sand Mould

Jixie Gongcheng Xuebao/Journal of Mechanical Engineering 2018年第17期54卷 124-132页

作者： Shan, Zhongde Zhu, Fuxian State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science Technology Beijing100044 China School of Materials Engineering Jiangsu University of Technology Changzhou213001 China

For the advantage of patternless casting technology in mould making, the wear mechanism of PCD tool is studied and the prediction models of wear ratio are built based on the sand mould milling experiments with polycrystalline diamond (PCD) tool. The micro phase morphology of wear zone of PCD tool is observed by scanning electron microscopy, from which the change rule with the processing time and the wear mechanism are studied. The results show that the high frequency scrape and impact of the raised sand particles on the flank during the sand milling process lead to the cleavage fracture of diamond particles and the scraping of the bonding material among the PCD particles in the surface of the tool, which cause the diamond particles to fall off. Furthermore, the microscopic defects in the tool and the "hard spots" in the sand mould cause the cutter micro chipping. Based on support vector machine (SVM) regression analysis algorithm, Matlab is used to compile the regression program of the ratio of wear to milling volume to build the prediction model of wear ratio based on the orthogonal experimental results. The influence of process parameters on tool wear ratio are predicted with the model, which can provide the basis for the wear control of the tool with high efficiency processing sand mould. © 2018 Journal of Mechanical Engineering.

关键词： Regression analysis

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Hybrid patternless forming method and equipment of multi-material sand mold 73

Hybrid patternless forming method and equipment of multi-mat...

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73rd World Foundry Congress: Creative Foundry, WFC 2018

作者： Shan, Zhongde Guo, Zhi Zhang, Shuai Liu, Feng Liu, Limin China Academy of Machinery Science and Technology Group Co. Ltd. Beijing100044 China Department of Mechanical Engineering Tsinghua University Beijing100084 China State Key Laboratory of Advanced Forming Technology and Equipment Beijing100083 China

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Embodied water analysis for Hebei Province, China by input-output modelling

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Frontiers of Earth Science 2018年第1期12卷 72-85页

作者： Siyuan LIU Mengyao HAN Xudong WU Xiaofang WU Zhi LI Xiaohua XIA Xi JI Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Qinhuangdao 066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao 066004 China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China College of Engineering Peking University Beijing 100871 China School of Economics Renmin University of China Beijing 100872 China School of Economics Peking University Beijing 100871 China

With the accelerating coordinated development of the Beijing-Tianjin-Hebei region, regional eco- nomic integration is recognized as a national strategy. As water scarcity places Hebei Province in a dilemma, it is of critical importance for Hebei Province to balance water resources as well as make full use of its unique advantages in the transition to sustainable development. To our knowledge, related embodied water accounting analysis has been conducted for Beijing and Tianjin, while similar works with the focus on Hebei are not found. In this paper, using the most complete and recent statistics available for Hebei Province, the embodied water use in Hebei Province is analyzed in detail. Based on input-output analysis, it presents a complete set of systems accounting framework for water resources. In addition, a database of embodied water intensity is proposed which is applicable to both intermediate inputs and final demand. The result suggests that the total amount of embodied water in final demand is 10.62 billion m3, of which the water embodied in urban household consumption accounts for more than half. As a net embodied water importer, the water embodied in the commodity trade in Hebei Province is 17.20 billion m3. The outcome of this work implies that it is particularly urgent to adjust industrial structure and trade policies for water conservation, to upgrade technology and to improve water utilization. As a result, to relieve water shortages in Hebei Province, it is of crucial importance to regulate the balance of water use within the province, thus balancing water distribution in the various industrial sectors.

关键词： input-output analysis Hebei Province embo-died water embodied water intensity

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Microstructural evolution and mechanical properties of Mg-9.8Gd-2.7Y-0.4Zr alloy produced by repetitive upsetting

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Journal of Materials Science & technology 2018年第7期34卷 1067-1075页

作者： H.Zhou H.Y.Ning X.L.Ma D.D.Yin L.R.Xiao X.C.Sha Y.D.Yu Q.D.Wang Y.S.Li Nano and Heterogeneous Materials Center School of Materials and EngineeringNanjing University of Science and TechnologyNanjing210094China Institute of Microstructure and Property of Advanced Materials Beijing University of TechnologyBeijing 100124China School of Mechanical and Electrical Engineering Heilongjiang Institute of TechnologyHeilongjiang 150050China School of Materials Science and Engineering Harbin University of Science and TechnologyHarbin 150040China Department of Materials Science&Engineering North Carolina State UniversityRaleighNC 27695USA Key Laboratory of Advanced Technologies of Materials Ministry of EducationSchool of Materials Science and EngineeringSouthwest Jiaotong UniversityChengduSichuan 610031China National Engineering Research Center of Light Alloys Net Forming and State Key Laboratory of Metal Matrix CompositeShanghai Jiao Tong University200240 ShanghaiChina

A newly developed severe plastic deformation （SPD） technique, i.e. repetitive upsetting （RU）, is employed to improve the strength and ductility of a Mg-Gd-Y-Zr alloy. During the RU processing, dynamic recrystallization occurs in the Mg alloy, which leads to a significant grain refinement from 11.2 p.m to 2.8 μm. The yield strength （YS）, ultimate tensile strength （UTS） and elongation increase simultaneously with increasing RU passes. The microstructural evolution is affected by processing temperatures. Dynamic recrystallization prevails at low temperatures, while dynamic recovery is the main effect factor at high temperatures. Texture characteristics gradually become random during multiple passes of RU processing, which reduces the tension-compression asymmetry of the Mg-Gd-Y-Zr alloy. 2018 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ technology.

关键词： Severe plastic deformation （SPD） Repetitive upsetting （RU） Mg-RE alloy Mechanical properties

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Microstructure and mechanical properties at elevated temperature of Mg-Al-Ni alloys prepared through powder metallurgy

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Journal of Materials Science & technology 2017年第9期33卷 947-953页

作者： Legan Hou Bingcheng Li Ruizhi Wu Lin Cui Peng Ji Ruiying Long Jinghua Zhang Xinlin Li Anping Dong Baode Sun Key Laboratory of Superlight Materials & Surface Technology Ministry of EducationHarbin Engineering University College of Civil and Architectural Engineering Heilongjiang Institute of Technology Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming Shanghai Jiao Tong University

Mg-Al-Ni alloys were prepared by powder metallurgy, and their microstructure and elevated temperature mechanical properties were investigated. Results indicate that, in addition to α-Mg matrix, both coarse Al;Ni;particles and fine Al Ni nano-particles exist in the Mg-Al-Ni alloys. The strength at 150?C is improved with the increase in Ni content. Mg-18.3Al-8Ni alloy possesses a compressive strength of234.7 MPa and a yield strength of 146.5 MPa. Plasticity is also improved with a low concentration of Ni. Mg-11.3Al-2Ni alloy possesses a compression ratio of 17.3%. The phases of Al;Ni;and Al Ni in the alloys block the movements of grain boundaries and dislocations during the deformation at elevated temperature. The existence of Al Ni phase provides a non-basal slip system, leading to the improvement in plasticity. Finally, the formation mechanism of Al-Ni phases in the process is discussed with thermodynamics and kinetics.

关键词： Mg-Al-Ni alloy Powder metallurgy Al3Ni2 AlNi

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What is going on in magnesium alloys？

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Journal of Materials Science & technology 2018年第2期34卷 245-247页

作者： X.J. Wang D.K. Xu R.Z. Wu X.B. Chen Q.M. Peng L. Jin Y.C. Xin Z.Q. Zhang Y. Liu X.H. Chen G. Chen K.K. Deng H.Y. Wang School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Key Laboratory of Superlight Materials & Surface Technology (Ministry of Education) Harbin Engineering University Harbin 150001 China School of Engineering RMIT University City Campus Carlton VIC 3053 Australia State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004 China National Engineering Research Center of Light Alloy Net Forming Shanghai Jiao Tong University Shanghai 200240 China College of Materials Science and Engineering Chongqing University Chongqing 400030 China Key Lab of Electromagnetic Processing of Materials Ministry of Education Northeastern UniversityShnenyang 110819China Key Laboratory of Lightweight and High Strength Structural Materials of Jiangxi Province Nanchang University Nanchang 330031 China School of Chemical Engineering and Technology Tianjin University Tianjin 300350 China Shanxi Key Laboratory of Advanced Magnesium-Based Materials Taiyuan University of Technology Taiyuan 030024 China Key Laboratory of Automobile Materials of Ministry of Education & School of Materials Science and Engineering Jilin University Changchun 130025 China

China has been developed into one of the most active regions in terms of both fundamental and applied research on magnesium （Mg） and its alloys in the world from a solid base laid by its prominent metallurgist and materials scientists over the past decades. Nowadays, a large number of young-generation researchers have been inspired by their predecessors and become the key participants in the fields of Mg alloys, which consequently led to the establishment of China Youth Scholar Society for Magnesium Alloys Research in 2015. Since then, the first two China Youth Scholars Symposiums on Mg Alloys Research had been held at Harbin （2015） and Chongqing （2016） China, respectively. A number of crucial research inter- ests related to fundamental and applied Mg research were discussed at the conferences and summarized in this short perspective, aiming to boost far-reaching initiatives for development of new Mg-based materials to satisfy the requirements for a broad range of industrial employments. Herein, four main aspects are included as follows： i） Plastic deformation mechanism and strengthening strategy, ii） Design and development of new Mg-based materials, iii） key service properties, and iv） New processing technologies.

关键词： Mg alloys Plastic deformation Strengthening Alloying design High performance Corrosion Fatigue behavior Creep Processing technologies Purification

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Effects of physical parameters of multiphase flow on fire water monitor based on Fluent

Effects of physical parameters of multiphase flow on fire wa...

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CSAA/IET International Conference on Aircraft Utility Systems (AUS 2018)

作者： Xiaoming Yuan Shiyi Zhao Chu Wang Lijie Zhang Hebei Key Laboratory of Heavy Machinery Fluid Power Transmission and Control with the Key Laboratory of Advanced Forging & Stamping Technology and Science Yanshan University Qinhuangdao China

ISBN: (纸本)9781510872745

To improve the jet performance of a fire water monitor, the monitor head with three different inner contour lines were designed. Based on FLUENT, the calculation domain was defined geometrically and then the cloud pictures of the flow velocity, pressure, turbulence kinetic energy and multiphase flow of the fluid field in the nozzle and jet were obtained, based on which the optimal structure of each model can be selected. The simulation result can provide the theoretical reference for the design of a monitor head.

关键词： Fire water monitor Jet performance Fluent

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Research on Fuzzy PID Control Algorithm for Lower Limb Rehabilitation Robot

Research on Fuzzy PID Control Algorithm for Lower Limb Rehab...

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IEEE Information technology and Mechatronics Engineering Conference (ITOEC)

作者： Hongbo Wang Tingting Lu Baoshan Niu Hao Yan Xincheng Wang Jianyu Chen Yungui Li Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Qinhuangdao China Parallel Robot and Mechatronic System Laboratory of Hebei Province

ISBN: (纸本)9781538653746

Cerebrovascular disease, hemiplegia and paraplegia may lead to lower extremity motor dysfunction. According to the theory of neural rehabilitation, proper rehabilitation training can help patients recover. In this paper, a lower limb rehabilitation robot is proposed, which can realize passive training and active training. Firstly, the mechanical structure and electrical system are designed. Secondly, in order to solve the problem of inaccurate parameters in the dynamic model of robot joint torque control, a fuzzy adaptive PID controller is established by combining negative feedback with PID regulator to eliminate the system error.

关键词： Training Rehabilitation robotics Legged locomotion PI control PD control Robot sensing systems

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Microstructures and Mechanical Properties of a new high entropy alloy

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IOP Conference Series: Materials Science and Engineering 2020年第1期772卷

作者： Mingju Chen Jing Yang School of Resources and Materials Northeastern University at Qinhuangdao Qinhuangdao 066004 PR China Key Laboratory of advanced metal materials and forming technology in Qinhuangdao Northeastern University at Qinhuangdao Qinhuangdao 066004 PR China State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004 PR China

All manuscripts must be in English, also the table and figure texts, otherwise we cannot publish your paper. Please keep a second copy of your manuscript in your office. When receiving the paper, we assume that the corresponding authors grant us the copyright to use the paper for the book or journal in question. Should authors use tables or figures from other Publications, they must ask the corresponding publishers to grant them the right to publish this material in their paper.

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Kinematic characteristics analysis and assembly application of a spatial symmetric 7R mechanism

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Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica 2019年第4期40卷 422536页

作者： Han, Bo Xu, Yundou Yao, Jiantao Zheng, Dong Zhang, Shuo Zhao, Yongsheng Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Qinhuangdao066004 China

A spatial symmetric 7R mechanism is proposed in this paper, constructing space deployable mechanisms. Firstly, the overall degree of freedom (DOF) is analyzed based on the screw constraint topology diagram, obtaining the variation of DOFs of the whole mechanism when the orientation of the joint axes changes. Then, the number and nature of DOFs of the motion output component in different orientations of the joint axes are analyzed based on the inverse screw theory. and the transient nature of the DOFs are analyzed. It is found that passive DOF and instantaneous DOF occurred in the arrangement of different joint axes orientations. Furthermore, the singular characteristics of the mechanism in different driving conditions are analyzed, obtaining the geometric conditions of the mechanism in the singular configuration under different driving conditions. Finally, a class of single-DOF polygonal pyramid-shaped space deployable mechanism is constructed by combining spatial symmetric 7R mechanisms with DOF at one. By setting the joint axes orientations, the mechanism yields a large folding rate, and due to its singular properties, it has good mechanical properties. Through the combination of a plurality of pyramid-shaped space deployable mechanisms, new large-scale space deployable mechanisms can be constructed, showing good application prospects in the aerospace field. © 2019, Press of Chinese Journal of Aeronautics. All right reserved.

关键词： Mechanisms

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