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RESEARCH ON BEHAVIORS OF ELECTRORHEOLOGIcaL FLUID-BASED SEMIACTIVE ROBOT FINGERTIPS

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Chinese Journal of mechanical engineering 1998年第2期11卷 17-22,29页

作者： Yue Hong Li Tiejun department of mechanical engineering, Hebei university of Technology Peng Yuqing cai Hegao Hebei university of Technology Harbin Institute of Technology Hebei Univ of Technology China

A new design of robot gripper with electrorheological fluid (ERF) semiactive tips is described. There are two remarkable properties using this fingertip. One is the higher lifting capability at little grasp force, which can realize stable grasp. Another is the damping controllable which can be used for controlling contact forces. A viscoelastic plastic model for normal direction of the fingertip is proposed to explore the contact behavior. The electric field strength is induced into the dynamic model of contact transition for simulations. The simulation results and conclusions are given.

关键词： Robot Semiactive fingertip Electrorheological fluid Dynamic model Simulation

ZERO TRANSMISSION AND ITS APPLIcaTION IN HIGH SPEED CNC MACHINE TOOLS

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Chinese Journal of mechanical engineering 2000年第3期13卷 184-189页

作者： Zhang Bolin, Ma Ping, Xiao Shuhong ,Li Yiping, Xiao Zhanglin (department of mechanical and Electronical engineering,Guangdong university of Technology) 广东工业大学广东广州

In order to realize high speed machining,the special requirements for the transmission and sturctrue of CNC machine tool have to be satisfied.A high speed spindle unit driven by a built-in motor is *** oil-water heat exchange system is used for cooling the spindle *** spindle is supported by Si_4N_3 ceramic ball angular contact bearings. An oil-air lubricator is used to lubricate and cool the spindle *** special structures are taken for balancing the spindle.

关键词： High speed machining Machine tool Spindle Ceramic ball bearing\

STUDY ON CONTROLLABILITY AND OBSERVABILITY FOR THIN PLATE SYSTEM WITH PARAMETER UNCERTAINTY

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Chinese Journal of mechanical engineering 1998年第3期11卷 60-67页

作者： Li Yiyang Ren Lihong Chen Guodong Liang Tianpei department of mechanical engineering, The Hong Kong Polytechnic university, Hong Kong Hong Kong Polytechnic Univ Hong Kong Hong Kong

The controllability and observability analysis of thin plate system with parameter uncertainty is presented using the degree of controllability/observability and the robustness index. It provides a guidance to the des... 详细信息

关键词： Degree of controllability/observability Robustness index Active vibration control

NUMERIcaL SIMULATION OF FLOW OVER TWO SIDE-BY-SIDE CIRCULAR CYLINDERS

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Journal of Hydrodynamics 2011年第6期23卷 792-805页

作者： SARVGHAD-MOGHADDAM Hesam NOOREDIN Navid GHADIRI-DEHKORDI Behzad department of mechanical engineering Neyshabur Branch Islamic Azad University department of mechanical engineering School of Engineering Tarbiat Modares University

In the present paper, the unsteady, viscous, incompressible and 2-D flow around two side-by-side circular cylinders was simulated using a cartesian-staggered grid finite volume based method. A great-source term technique was employed to identify the solid bodies （cylinders） located in the flow field and boundary conditions were enforced by applying the ghost-cell technique. Finally, the characteristics of the flow around two side-by-side cylinders were comprehensively obtained through several computational simulations. The computational simulations were performed for different transverse gap ratios （1.5≤T/D≤4） in laminar （Re=100,200） and turbulent （Re=104） regimes, where T and D are the distance between the centers of cylinders and the diameter of cylinders, respectively. The Reynolds number is based on the diameter of cylinders,D. The pressure field and vorticity distributions along with the associated streamlines and the time histories of hydrodynamic forces were also calculated and analyzed for different gap ratios. Generally, different flow patterns were observed as the gap ratio and Reynolds number varied. Accordingly, the hydrodynamic forces showed irregular variations for small gaps while they took a regular pattern at higher spacing ratios.

关键词： side-by-side cylinders vortex shedding flow induced forces finite volume method turbulent flow

A HIGH VELOCITY FEED UNIT DRIVEN BY LINEAR MOTOR

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Chinese Journal of mechanical engineering 2000年第4期13卷 266-272页

作者： Zhang Bolin Chen Yanji Li Zhiying Liu Yurong Luo Yong (department of mechanical and Electronical engineering， Guangdong university of Technology) 广东工业大学广东广州

In order to realize high speed machining, the special requirements for feed transmission system of the CNC machine tool have to be satisfied. A high velocity feed unit driven by a induction linear motor is developed. ... 详细信息

关键词： High speed machining Machine tool Feed system Linear motor

CONTACT DEFORMATION AND PRE-CONTROL OF TRANSMISSION PROPERTIES OF POINT CONJUGATE GEAR

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Chinese Journal of mechanical engineering 2000年第1期13卷 76-80页

作者： Liu Huran Yuan Wenhui (department of mechanical engineering, Changsha Railway Institute) Li Rongbin (The Hong Kong Polytechnic university) 长沙铁道学院湖南长沙香港理工大学香港

According to spatial conjugate principle and theory of elastic contact, a method to pre-control transmission properties and contact mark of point meshing gear is presented, while the deformation of tooth surface is un... 详细信息

关键词： Elastic Contact Deformation Meshing Gear

Optimization of a serpentine flow field with variable channel heights and widths for PEM fuel cells

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Science China(Technological Sciences) 2010年第2期53卷 453-460页

作者： LIN Lin, ZHANG XinXin, FENG HuTing & WANG XiaoDong department of Thermal engineering, School of mechanical engineering, university of Science and Technology Beijing, Bejing 100083, China department of Thermal engineering School of Mechanical Engineering University of Science and Technology Beijing

The present study proposes a modified serpentine flow field design in which the channel heights vary along each straight flow path to enhance reactant transport and liquid water removal. An optimization approach, combining a simplified conjugate-gradient method (inverse solver) and a three-dimensional, two-phase, non-isothermal fuel cell model (direct solver), has been developed to optimize the key geometric parameters. The optimal design has tapered channels for channels 1, 3 and 4 and increasing heights for channels 2 and 5 with the flow widths first increasing and then decreasing. The optimal channel heights and widths enhance the efficiency by 22.51% compared with the basic design having all heights and widths of 1 mm. The diverging channels have a greater impact on cell performance than fine adjustments of the channel widths for the present simulation conditions. The channel heights have more effect on the sub-rib convection, while the channel widths affect the uniformity of the fuel delivery more. The reduced channel heights of channels 2–4 significantly enhance the sub-rib convection to effectively transport oxygen to and liquid water out of the diffusion layer. The final diverging channel prevents significant leakage of fuel to the outlet via sub-rib convection.

关键词： PEM fuel cell simplified conjugate-gradient method optimization sub-rib convection

Effect of Process Factors on Microstructure of Semisolid Continuous casting Billets

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 242-245页

作者： Shuming Xing, Qijie Zhai, Hanqi Hu ( department of mechanical engineering, Tsinghua university, Beijing 100084, China School of Material Science and engineering, Shanghai university, Shanghai 200072, China Material Science and engineering School, Univer department of mechanical engineering Tsinghua University Beijing 100084 China School of Material Science and engineering Shanghai University Shanghai 200072 China Material Science and engineering School University of Science and Technology Beijing Beijing 100083 China

Semisolid continuous casting (SSCC) is a new technology to produce billets for semisolid metal forming (SSMF). The effect of process factors, such as pouring temperature, stirring rate, preheating temperature and thermal conductivity of stirring chamber, on the microstructure of SSCC billets was studied by means of the factorial experimental method. The results show that the microstructure of SSCC billets can be controlled by the above-mentioned four process factors. In order to obtain fine and rounded granular grains in an SSCC billet, the pouring temperature, preheating temperature and stirring rate should be kept in a moderate range, and the thermal conductivity of stirring chamber should be high. The regression equations with the process factors connecting the microstructure was also set up based on experimental data.

关键词： semisolid metal continuous casting process factors microstructure Metallurgy

Effects of Ta Addition on Microstructure and Transformation Behavior of Ni-Ti Alloys

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Journal of Materials Science & Technology 2001年第1期17卷 5-6页

作者： K.H.Wu and JL.Ma department of mechanical engineering, Florida International university, Miami, FL 33174, U.S.A. Dep. of Mech. Eng. Florida Int. Univ. Miami 33174 United States

The effect of adding Ta on the changes of microstructure and Ms temperature of a dualphase shape memory alloy with compositions of (Ni51 Ti49)1 -***. and Ni50-Ti50 -***.g were systematically studied. An optical microscope, SEM, X-ray diffraction and DSC were utilized in this work. The evolution of the microstructure as a function of Ta content was characterized. The variation of the Ni/Ti ratio in the NiTi phase plays an important role in the change of the Ms temperatures due to the addition of Ta. A pseudobinary NiTi-Ta phase diagram was proposed based on these results.

关键词： Ti Ta Effects of Ta Addition on Microstructure and Transformation Behavior of Ni-Ti Alloys