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Lift enhancement method by synthetic jet circulation control

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Science China(Technological Sciences) 2012年第9期55卷 2585-2592页

作者： ZHANG PanFeng YAN Bo DAI ChenFeng state key laboratory of mechanical system and vibration Shanghai Jiao Tong UniversityShanghai 200240China Institute of Fluid Mechanics Beijing University of Aeronautic and AstronauticsBeijing 100191China key laboratory of Fluid Mechanics Ministry of EducationBeijing 100191China

A novel circulation control technique is proposed to overcome the shortcomings of blowing jet circulation control,which uses the synthetic jet as the actuator and avoids the limitation about air supply *** effectiveness of synthetic jet circulation control to enhance lift of NCCR1510-7067N airfoil is confirmed by solving the 2-D unsteady Reynolds-averaged Navier-Stokes *** aerodynamic characteristics and the flow structure(especially close to the trailing edge) of NCCR1510-7067N airfoil at zero angle of attack are also presented to discuss the mechanism of lift enhancement of the airfoil with synthetic jet circulation *** results indicate that the synthetic jet can effectively delay the separation point on the airfoil trailing edge and increase the circulation and lift of the airfoil by Coanda *** numerical simulation results demonstrate that the lift augmentation efficiency with synthetic jet circulation control reaches △CL/Cμ=114 in the present study,which is much higher than the value 12.1 in the case with steady blowing jet circulation control.

关键词：循环控制合成射流 Navier-Stokes方程增强方法空气动力特性控制技术执行机构雷诺平均

Wearable Robots for Human Underwater Movement Ability Enhancement:A Survey

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IEEE/CAA Journal of Automatica Sinica 2022年第6期9卷 967-977页

作者： Haisheng Xia Muhammad Alamgeer Khan Zhijun Li MengChu Zhou IEEE Department of Automation University of Science and Technology of ChinaHefei 230026China Institute of Artificial Intelligence Hefei Comprehensive National Science CenterHefei 230026China Helen and John C.Hartmann Department of Electrical and Computer Engineering New Jersey Institute of TechnologyNewark NJ 07102 USA Department of Cyber-Physical systems St.Petersburg State Marine Technical UniversitySt.Petersburg 198262Russia

Underwater robot technology has shown impressive results in applications such as underwater resource *** underwater applications that require extremely high flexibility,robots cannot replace skills that require human dexterity yet,and thus humans are often required to directly perform most underwater *** robots(exoskeletons)have shown outstanding results in enhancing human movement on *** are expected to have great potential to enhance human underwater *** purpose of this survey is to analyze the state-of-the-art of underwater exoskeletons for human enhancement,and the applications focused on movement assistance while excluding underwater robotic devices that help to keep the temperature and pressure in the range that people can *** work discusses the challenges of existing exoskeletons for human underwater movement assistance,which mainly includes human underwater motion intention perception,underwater exoskeleton modeling and human-cooperative *** research should focus on developing novel wearable robotic structures for underwater motion assistance,exploiting advanced sensors and fusion algorithms for human underwater motion intention perception,building up a dynamic model of underwater exoskeletons and exploring human-in-theloop control for them.

关键词： Cyborg intelligence diving exoskeleton intention perception modeling and control swimming underwater exoskeletons underwater robots wearable robots

Effect of carbon nanotubes on friction and wear of a piston ring and cylinder liner system under dry and lubricated conditions

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Friction 2017年第2期5卷 147-154页

作者： Zhinan ZHANG Jun LIU Tonghai WU Youbai XIE state key laboratory of mechanical system and vibration Shanghai Jiao Tong University Shanghai 200240 ChinaSchool of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China School of mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China key laboratory of Education Ministry for Modern Design and Rotor-Bearing system Xi'an Jiaotong University Xi'an 710049 China

This study involves the application of carbon nanotubes (CNTs) to a piston ring and cylinder liner system in order to investigate their effect on friction and wear under dry and lubricated conditions. Carbon nanotubes were used as a solid lubricant and lubricant additive in dry and lubricated conditions, respectively. Simulation and measurement of friction and wear were conducted using a reciprocating tribometer. Surface analysis was performed using a scanning electron microscope and an energy dispersive spectrometer. The results indicate that carbon nanotubes can considerably improve the tribological performance of a piston ring and cylinder liner system under dry sliding conditions, whereas improvement under lubricated conditions is not obvious. Under dry friction, the effective time of the CNTs is limited and the friction coefficient decreases with an increase in CNT content. Furthermore, the dominant wear mechanism during dry friction is adhesive.

关键词： carbon nanotubes piston ring tribological behavior friction wear

Blow-by and tribological performance of piston ring pack during cold start and warm idle operations

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Science China(Technological Sciences) 2016年第7期59卷 1085-1099页

作者： CHENG Jun MENG XiangHui XIE YouBai KONG XiaoLi School of mechanical Engineering Shanghai Jiaotong University Shanghai 200240 China research and Development Center of China's First Automotive Works (FAW) Group Changchun 130011 China

To reduce the fuel consumption of internal combustion engines, more attention has been paid to the tribological performance of the piston ring pack during the cold start and idle operations. In this research, a numerical model considering the cylinder liner deformation and the piston ring conformability is developed to predict the blow-by, lubrication, friction and wear of the piston ring pack under different operating conditions. The gas flow rate, inter-ring gas pressures, minimum oil film thickness, frictional force and wear load during cold start are calculated and compared with those during warm idle operating conditions. The results show that cylinder liner deformation and piston ring conformability together obviously affect blow-by and other tribological performance. Meanwhile, it is found that friction loss is larger during cold start than during warm idle operating conditions. However, the wear process is more severe during warm idle operation than during cold start. From this research, the blow-by and tribological performance of the piston ring pack during cold start and warm idle operations are understood more deeply.

关键词：摩擦磨损性能活塞环组怠速工况操作过程冷启动最小油膜厚度气体流量启动过程

Trajectory control strategy of cathodes in blisk electrochemical machining

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Chinese Journal of Aeronautics 2013年第4期26卷 1064-1070页

作者： Zhu Dong Zhu Di Xu Zhengyang Zhou Laishui College of mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics state key laboratory of mechanical system and vibration Shanghai Jiao Tong University

A turbine blisk, which combines blades and a disk together, is one of the most important components of an aero engine. In the process of blisk electrochemical machining （ECM）, the sheet cathode, which is usually used as a tool electrode, has a complicated structure. In addition to that, the channel between the adjacent blades is narrow and twisted, so interference is apt to happen when the sheet cathode feeds into the channel. Therefore, it is important to choose suitable trajectory control strategy. In this paper, a new trajectory control strategy of the sheet cathode is presented and corresponding simulation analysis is conducted on the basis of an actual blisk model. The simulation results demonstrate that the sheet cathode can feed into the channel by a spatial line trajectory without interference. Moreover, the verification experiments are carried out according to the simulation. The experimental results show that the cathode can move into the channel without interference. It is verified that the new trajectory control strategy is correct and can be used in the blisk ECM process successfully.

关键词： Blisk Cathodes Electrochemical machining Feed Trajectory control

Multiscale Theories and Applications:From Microstructure Design to Macroscopic Assessment for Carbon Nanotubes Networks

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Chinese Journal of mechanical Engineering 2023年第3期36卷 18-35页

作者： Jiachao Ji Yulin Jin Anping Hua Chunhua Zhu Junhua Zhao Jiangsu key laboratory of Advanced Food Manufacturing Equipment and Technology Jiangnan UniversityWuxi 214122China Institute of Mechanics and Advanced Materials School of Mechanical EngineeringJiangnan UniversityWuxi 214122China

Carbon nanotube(CNT)networks enable CNTs to be used as building blocks for synthesizing novel advanced materials,thus taking full advantage of the superior properties of individual *** analyses have to be adopted to study the load transfer mechanisms of CNT networks from the atomic scale to the macroscopic scale due to the huge computational *** them,fully resolved structural features include the graphitic honeycomb lattice(atomic),inter-tube stacking(nano)and assembly(meso)of *** an atomic scale,the elastic properties,ultimate stresses,and failure strains of individual CNTs with distinct chiralities and radii are obtained under various loading conditions by molecular *** dependence of the cohesive energies on spacing distances,crossing angles,size and edge effects between two CNTs is analyzed through continuum modeling in *** mesoscale models,which neglect the atomic structures of individual CNTs but retain geometrical information about the shape of CNTs and their assembly into a network,have been developed to study the multi-level mechanism of material deformation and microstructural evolution in CNT networks under stretching,from elastic elongation,strengthening to damage and *** paper summarizes the multiscale theories mentioned above,which should provide insight into the optimal assembling of CNT network materials for elevated mechanical performance.

关键词： Carbon nanotube networks Hierarchical structures Multiscale theories Mesoscale model

Gait fitting for snake robots with binary actuators

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Science China(Technological Sciences) 2014年第1期57卷 181-191页

作者： MIAO YunJie GAO Feng ZHANG Yong state key laboratory of mechanical system and vibration Shanghai Jiao Tong University

Thanks to the special physical architectures and various locomotion gaits,snake robots may offer significant benefits over traditional legged or wheeled locomotion designs in vast types of *** paper proposes an innovative snake robot with digitally-actuated Stewart platforms as its modules and mainly focuses on the simulations of various snake *** categories of fitting algorithms are elaborated in simulations of lateral undulation and Configuration-Fitting Algorithm of Four Modules is demonstrated as a universal gait fitting algorithm for all kinds of snake robots with binary *** typical snake gaits are simulated and the results demonstrate the excellent mobility of the snake robot.

关键词：蛇形机器人运动步态拟合算法执行器二进制物理结构运动设计数字化

Tribo-informatics:Concept,architecture,and case study

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Friction 2021年第3期9卷 642-655页

作者： Zhinan ZHANG Nian YIN Shi CHEN Chengliang LIU Stake key laboratory of mechanical system and vibration Shanghai Jiao Tong UniversityShanghai 200240China School of mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Friction plays a vital role in energy dissipation,device failure,and even energy supply in modern *** years of research,data and information on tribology research are becoming increasingly *** of the strong systematic and multi-disciplinary coupling characteristics of tribology,tribology information is scattered in various disciplines with different patterns,e.g.,technical documents,databases,and papers,thereby increasing the information entropy of the system,which is inconducive to the preservation and circulation of research *** the development of computer and information science and technology,many subjects have begun to be combined with information technology,and multi-disciplinary informatics has been *** paper describes the combination of information technology with tribology research,presenting the connotation and architecture of tribo-informatics,and providing a case study on implementing the proposed concept and *** proposal and development of tribo-informatics described herein will improve the research efficiency and optimize the research process of tribology,which is of considerable significance to the development of this field.

关键词： tribo-informatics database tribology information technology

A Method to Analyze the Voltage-Actuation Response of a Pre-Strained Circular Dielectric Elastomer Actuator Model

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Journal of Shanghai Jiaotong university(Science) 2017年第3期22卷 334-342页

作者：陈名光李锦轩福贞 School of mechanical and Power Engineering East China University of Science and Technology Shanghai 200237China

Dielectric elastomers(DEs) are the polymers capable of inducing deformation under electrical stimulation. When subject to a voltage across its thickness, the material reduces in thickness and expands in area. This paper presents a new method to analyze deformation and stress distribution response of the dielectric elastomer actuator(DEA) model under different applied voltage. An equal-biaxial pre-strained circular actuator model was built. The Yeoh strain energy potential and the collocation method are used for describing the large strain actuation response and stress distribution. The study in this paper has shown that: the stress and the stretch distributions in the passive region of the DE actuator depend on the radial distance from the center at the calculation point of the passive region and the magnitude of the applied voltage; with the same excitation applied voltage, we can get a larger deformation actuation by choosing an appropriate pre-stretch ratio; the influence of the non-ideal material has seriously affected the actual deformation of the DE actuators. This analytical model has a reference potential for the design optimization of high performance DEA systems and the model-based control of the DEA robot.

关键词： dielectric elastomer circular actuator Yeoh model actuation