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Mechanism of plasticity enhancement of AZ31B magnesium alloy sheet by accumulative alternating back extrusion

Journal of Magnesium and Alloys 2023年第5期11卷 1791-1801页

作者： Ye Wang Feng Li Nan Bian Hua Qiu Du Peng Da Huo School of Materials Science and Engineering Harbin University of Science and TechnologyHarbin 150040PR China Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of EducationHarbin University of Science and TechnologyHarbin 150080PR China

Accumulative alternating back extrusion was a potential fine-grain modification *** this paper,it was an innovative attempt to develop high-performance magnesium alloy sheet by this *** the condition of 350 K,commercial AZ31 magnesium alloy was made into billet by accumulative alternating back extrusion,and then extruded into fine-grain magnesium alloy *** a systematic study of its microstructure and mechanical properties,the results showed that the initial state had an important influence on the evolution of the structure during *** accumulative alternating back extrusion to produce the billet,the grain size of the sheet obtained by extrusion was significantly refined,which was related to the accumulation of deformation and grain refinement during the alternating loading *** refinement caused the proportion of dynamic recrystallization inside the sheet with 2 cycles of accumulative alternating back extrusion to drop to 27%.With the increase of extrusion cycles from 2 to 4,the high density of dislocations led to an increase in the proportion of dynamic recrystallization and finer *** texture changed from strong basal texture to weak bimodal *** results of uniaxial tensile test show that due to grain refinement and texture change,the yield strength was significantly reduced,and the plasticity was significantly *** was verified that accumulative alternating back extrusion was meaningful for subsequent processing,and it also provided scientific guidance for the development of fine-grained magnesium alloy sheet.

关键词： Magnesium alloy Alternating back extrusion Microstructure uniformity Bimodal texture Texture weakening Sheet anisotropy

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Design and Simulation of a New Quality Underwater Swarm Inspired by Biological Models 24

Design and Simulation of a New Quality Underwater Swarm Insp...

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3rd International Symposium on Robotics, Artificial Intelligence and Information engineering, RAIIE 2024

作者： Huang, Silun Wang, Xingbo Wang, Chuyan Zhang, Jiwen Xu, Bo School of Future Technology Harbin Engineering University Harbin150001 China School of Intelligent Science and Engineering Harbin Engineering University Harbin150001 China

ISBN: (纸本)9798400718311

To solve the problem of underwater multi-target group search and enable the group system to conduct low-volume agile regulation through implicit communication, thereby promoting the development of new-quality underwater group cooperative technology, a new-quality group search model was established based on biological inspiration models within the framework of traditional artificial fish swarm algorithm, starting from the characteristics of the new-quality underwater group system. The model was then validated through simulation of multi-thermal vent search mission. To enhance the reliability of the model, temperature field models, sea current models, and biomimetic fish movement models of thermal vents in the three-dimensional underwater environment were established to improve system parameters. Ultimately, compared with the traditional artificial fish swarm model, the new-quality group search model improved search efficiency, stability, and global convergence. © 2024 Copyright held by the owner/author(s). Publication rights licensed to ACM.

关键词： Fish

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Double effects of recrystallization behavior on grain morphology evolution and mechanical properties of Al/Mg/Al composite plate by hard plate rolling

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Progress in Natural science:Materials International 2024年第5期34卷 1029-1038页

作者： Jia Yang Zhang Feng Li Fu Wei Kang Zi Yi Wang Lu Sun School of Materials Science and Chemical Engineering Harbin University of Science and Technology Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of Education Harbin University of Science and Technology Heilongjiang Provincial Key Laboratory of Light Metal Materials Modification & Green Forming Technology Harbin University of Science and Technology

Enhancing the bonding strength, optimizing the microstructure and refining the properties represent effective strategies for the fabrication of heterogeneous composite plates. In this study, composite plates of Al/Mg/Al were fabricated through hard plate rolling(HPR) with a reduction in rolling ranging from 40 % to 80 %. The research primarily concentrates on the substrate in the influence of rolling dynamic recrystallization(DRX) behavior on the grain morphology evolution and mechanical properties of AZ31 magnesium alloy sheets during the process. The findings indicate that at a compression amount of 60 %, the composite plate exhibits an ultimate tensile strength(UTS), a maximum elongation(EL) of 12.5 %, and improved interface bonding. Comparative analysis reveals the occurrence of DRX on the Mg side, resulting in the formation of small DRXed grains being generated. With an increase in reduction, DRX is facilitated, leading to an initial rise and subsequent decline in the proportion of DRXed grains. The proliferation of fine grains hinder dislocation movement, thereby reinforcing composite ***, an elevation in the degree of recrystallization enhances the initiation of non-basal slip and enhances the plasticity of sheet metal. This study offers valuable scientific guidance and technical assistance for the production of forming high-quality Mg–Al composite plates.

关键词： Hard plate rolling Al/Mg/Al Composite plate Dynamic recrystallization Mechanical properties

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Analysis and Zonation of Freeze–Thaw Action in the Chinese Plateau Region Considering Spatiotemporal Climate Characteristics

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engineering 2024年第11期42卷 308-325页

作者： Tiejun Liu Ming Zhang Dujian Zou Jiaping Liu Jinping Ou School of Civil and Environmental Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China Guangdong Provincial Key Laboratory of Intelligent and Resilient Structures for Civil Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China School of Materials Science and Engineering Southeast UniversityNanjing 211189China

Concerns about the durability of transportation infrastructure due to freeze-thaw(F-T)cycles are particu-larly significant in the Chinese plateau region,where concrete aging and performance deterioration pose substantial *** current national standards for the frost resistance design of concrete struc-tures are based predominantly on the coldest monthly average temperature and do not adequately address the comprehensive effects of the spatiotemporal variance,amplitude,and frequency of F-T *** address this issue,this study introduced a spatiotemporal distribution model to analyze the long-term impact of F-T action on concrete structures by employing statistical analysis and spatial inter-polation *** analysis was applied to create a nationwide zonation of F-T action level from data on the freezing temperature,temperature difference,and the number of F-T ***,this study explored the similarity between natural environmental conditions and laboratory-accelerated tests using hydraulic pressure and cumulative damage theories.A visualization platform that incorporates tools for meteorological data queries,environmental characteristic analyses,and F-T action similarity calculations was *** research lays theoretical groundwork and provides technical guidance for assessing service life and enhancing the quantitative durability design of concrete structures in the Chinese plateau region.

关键词： Concrete durability Freeze-thaw(F-T) Environmental characteristics Similarity Zonation

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Two-cylinder Synchronous Electro-hydraulic Servo system and its Control Technology Development

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Recent Patents on engineering 2024年第7期18卷 116-134页

作者： Li, Jianying Ji, Hui Kong, Lingbing Jiang, Liqun Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of Education Harbin China School of Mechanical and Power Engineering Harbin University of Science and Technology Harbin China

Background: Electro-hydraulic servo control system synchronous control in industrial application is very extensive because the application of electro-hydraulic servo control system is mostly in a poor working environment, there are a variety of complex external factors. Objective: Improve the comprehensive performance indicators such as accuracy, speed, and stability of synchronous control of hydraulic cylinders Methods: In the process of synchronous movement, the typical hardware structure and control methods and algorithm strategies of the double hydraulic cylinder are analyzed in detail, and the basic principle of common hydraulic double cylinder synchronous control is summarized. Results: Through the comprehensive analysis of papers and patent documents related to the synchronous control of hydraulic twin cylinders, these papers and patented technologies study the control algorithm, and apply the new technology to the synchronous control of electro-hydraulic servo hydraulic cylinders to improve its comprehensive performance indicators such as work ac-curacy, speed and stability. Conclusion: Referring to the development trajectory of control algorithms in this regard, combined with new control theory and new technology, many achievements can be applied and re-searched in hydraulic cylinder synchronous control, and better develop the synchronous control system when double hydraulic cylinders and more hydraulic cylinders work together. By collating and analyzing the relevant research results, the two-cylinder synchronous control technology is comprehensively evaluated and prospected, which provides a valuable reference for the research and application in this field. © 2024 Bentham science Publishers.

关键词： Cylinders (shapes)

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DCM-based dynamic stable walking under terrain-induced time-varying disturbances for humanoid robots

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science China(Technological sciences) 2025年第4期68卷 105-117页

作者： Yan LUO Chao LIU Jianhua WU Zhenhua XIONG Han DING State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China

When humanoid robots attempt to walk on terrain such as shaking platforms,time-varying disturbances are introduced to the support *** abrupt changes of inclination angle can cause the robot to lose balance upon landing,presenting significant challenges for balance control *** address this issue,we propose a novel divergent component of motion(DCM)-based time-varying disturbance walking(DCM-TVDW)*** method allows the robot to walk on rugged surfaces and helps to maintain dynamic balance when subjected to large time-varying *** the DCM-TVDW control method,we first adjust the robot's center of mass and stride height to adapt to transitions between different terrain types via a variable height stabilization method,and hold these quantities constant as base *** then combine DCM with the N-step capturability *** combination allows for dynamic balance through multi-step adjustments from the initially unstable region,thereby extending the robots stability *** and experimental results demonstrate that the DCM-TVDW method enables the SJ-Bruce robot to traverse a dynamically shaking platform with an inclination angle of approximately 22°.

关键词： humanoid robot dynamic balance control capturability time-varying disturbance

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Review of Patent Preparation of Medical Tracheal Stents

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Recent Patents on engineering 2024年第10期18卷 42-65页

作者： Bao, Yudong Wang, Siyuan Zhan, Yang School of Mechanical and Power Engineering Harbin University of Science and Technology Harbin150080 China Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of Education Harbin University of Science and Technology Harbin150080 China

Background: The trachea is an important part of the respiratory system, which is tubular. The upper part of the trachea connects to the throat, and its lower left and right branches lead to the lungs. The foreign body, compression of organs, and destruction of the tracheal ring can cause trachea stenosis. Mild tracheal stenosis can cause difficulty breathing, while severe tracheal stenosis can lead to death from respiratory failure, seriously endangering patients' quality of life. Tracheal stents are a prosthesis that addresses tracheal lumen obstruction or stenosis and maintains the diameter and patency of the lumen structure by providing internal support in resistance to external pressure to relieve patients' symptoms. Objective: This patent paper reviews the preparation methods of tracheal stents with various structures and similar vascular stents in recent years, looks for the deficiencies of existing preparation methods of tracheal stents, and finds new preparation methods to solve the functional defects of existing tracheal stents. Methods: Review the preparation patents of tracheal and vascular stents in recent years, and then analyze their advantages and disadvantages to find the improvement ideas of current tracheal stents to provide a direction for the future development of tracheal stent preparation technology. Results: Through the analysis and discussion of the existing technology, the existing problems and the future development direction of the tracheal stent preparation technology are found. Conclusion: A complete set of stent preparation technology for children should be designed for smaller stents, focusing on developing better-performance composite materials, and the new preparation technology should focus on the composite of various existing preparation technologies. In the future, we should pay attention to developing the preparation technology for tissue engineering stents. © 2024 Bentham science Publishers.

关键词： Tissue

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Monte-Carlo based random passive energy beamforming for reconfigurable intelligent surface assisted wireless power transfer

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Digital Communications and Networks 2023年第3期9卷 667-676页

作者： Ziyang Lu Yubin Zhao Xiaofan Li School of Microelectronics Science and Technology Sun Yat-Sen UniversityZhuhai519082China School of Intelligent System Science and Engineering Jinan UniversityZhuhai519070China

Reconfigurable intelligent surface(RIS)employs passive beamforming to control the wireless propagation channel,which benefits the wireless communication capacity and the received energy efficiency of wireless power transfer(WPT)*** beamforming schemes are classified as discrete and non-convex integer program-ming *** this paper,we propose a Monte-Carlo(MC)based random energy passive beamforming of RIS to achieve the maximum received power of electromagnetic(EM)WPT ***,the Gibbs sampling and re-sampling methods are employed to generate phase shift vector *** the sample with the maximum received power is considered the optimal *** order to adapt to the application scenarios,we develop two types of passive beamforming algorithms based on such MC sampling *** first passive beamforming uses an approximation of the integer programming as the initial sample,which is calculated based on the channel *** the second one is a purely randomized algorithm with the only total received power *** proposed methods present several advantages for RIS control,e.g.,fast convergence,easy implementation,robustness to the channel noise,and limited feedback requirement,and they are applicable even if the channel information is *** to the simulation results,our proposed methods outperform other approxi-mation and genetic *** our methods,the WPT system even significantly improves the power effi-ciency in the nonline-of-sight(NLOS)environment.

关键词： Reconfigurable intelligence surface Wireless power transfer Monte-carlo algorithm Passive beamforming Gibbs sampling

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Collision avoidance path planning method combining improved DWA and A* algorithms in complex sea environments

Collision avoidance path planning method combining improved ...

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2024 China Automation Congress, CAC 2024

作者： Liu, Liqiang Sun, Min Zhang, Zhenxing Zhao, Enjiao School of Information and Electronic Engineering Zhejiang University of Science and Technology Hangzhou China School of Intelligent Science and Engineering Harbin Engineering University Harbin China

ISBN: (纸本)9798350368604

This paper proposes a collision avoidance path planning method that combines the improved DWA algorithm with the A* algorithm to address navigation challenges in complex sea environments. First, a simplified grid map is constructed based on electronic chart data and the start and end points of the path planning, while the physical information of the ship is determined. The improved DWA algorithm is then used for collision avoidance path planning. When the ship reaches a safe distance from an obstacle, the improved A* algorithm is triggered to plan a path, and redundant points in the returned path are extracted to obtain key waypoints. These waypoints are used as temporary target points for the DWA algorithm, and the improved DWA algorithm is further applied for collision avoidance path planning. The improvements in the DWA algorithm mainly focus on the trajectory evaluation function, while the enhancements in the A* algorithm focus on the heuristic function. Finally, by combining the proposed algorithm with rich multi-source marine environment data and target fusion data, the ship's intelligent collision avoidance decision-making system is able to generate the optimal collision avoidance path in complex water environments. Simulation results demonstrate that the proposed method can effectively plan a safe and efficient collision avoidance path. © 2024 IEEE.

关键词： A* algorithm collision avoidance decision-making complex sea environments Dynamic Window Approach (DWA) path planning

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Review of Development and Characteristics Research on Electro-hydraulic Servo system

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Recent Patents on engineering 2024年第6期18卷 140-154页

作者： Li, Jianying Kong, Lingbing Liang, Heng Li, Weidong Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of Education Harbin University of Science and Technology Harbin150080 China School of Mechanical and Power Engineering Harbin University of Science and Technology Harbin150080 China

Background: The nonlinear problem of the electro-hydraulic servo system directly af-fects the system accuracy, response speed and other indicators, and the resulting problems of control inaccuracy and response delay urgently need to be solved. Method: This article provides an overview of the working principle of electro-hydraulic servo sys-tems, reviews the development history of electro-hydraulic servo systems, and summarizes the current research difficulties and latest patents of electro-hydraulic servo systems from the characteristics of active and passive loading systems, electro-hydraulic servo system multi flexibility charac-teristics, gap nonlinearity,parameter time-varying characteristics,mathematical modeling,force tracking accuracy control strategy, etc. Result: A large number of scholars have proposed the latest optimization strategies to address the nonlinear problems in various aspects of the electro-hydraulic servo system, effectively improving the control accuracy and static and dynamic characteristics of the electro-hydraulic servo system. Conclusion: By summarizing the latest progress in the study of nonlinear problems in various links of electro-hydraulic servo systems, it has played a guiding role in their future improvement and optimization strategies. © 2024 Bentham science Publishers.

关键词： Hydraulic servomechanisms

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