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HYDRODYNAMIC STUDY ON A PECTORAL FIN ROWING MODEL OF A FISH

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Journal of Hydrodynamics 2009年第4期21卷 463-472页

作者： HU Wen-tong department of Engineering Mechanics Shanghai Jiao Tong University Shanghai 200240 China

Fish pectoral fin movement involves primarily a drag-based and a lift-based mechanisms to produce thrust. A numerical study on a pectoral fin rowing propulsion model based on the drag-based mechanism is presented in this article. The propulsive mechanism of the pectoral fin rowing model is related with the voriticity and pressure in the flow field. The relationship between the thrust and kinematic parameters and the wake-captured problem are analyzed. It is shown that a high thrust is produced in the power stroke, mainly due to the backward translation acceleration, the anticlockwise angular acceleration and the absence of stall in the uniform translation. Moreover, the flow control mechanism and the effect of dynamic flexible deformation are further analyzed. To properly choose controllable factors and adopt an appropriate dynamic deformation can improve the propulsive performance.

关键词： pectoral fin drag-based propulsion propulsion mechanism computational fluid dynamics

Arm/trunk motion generation for humanoid robot

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Science china(Information Sciences) 2010年第8期53卷 1603-1612页

作者： XING DengPeng & SU JianBo department of Automation, shanghai jiao tong university, shanghai 200240, china 1. department of Automation Shanghai Jiao Tong University Shanghai 200240 China

This paper develops two motion generation methods for the upper body of humanoid robots based on compensating for the yaw moment of whole body during motion. These upper body motions can effectively solve the stability problem of feet spin for robot walk. We analyze the ground reactive torque, separate the yaw moment as the compensating object and discuss the effect of arms swinging on whole body locomotion. By taking the ZMP as the reference point, trunk spin motion and arms swinging motion are generated to improve the biped motion stability, based on compensating for the yaw moment. The methods are further compared from the energy consumption point of view. Simulated experimental results validate the performance and the feasibility of the proposed methods.

关键词： humanoid robot motion generation yaw moment arms swinging compensation motion

The ACL Property of Homeomorphisms under Weak Conditions

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Acta Mathematica Sinica,English Series 1998年第4期14卷 473-480页

作者： Fang Ainong, department of mathematics, shanghai jiao tong university, shanghai 200030, china department of mathematics Shanghai Jiao Tong University

Suppose that D is a domain in (n 2) and y= f(x): D → R^n is a homeomorphism. We prove that if the modulus dilatation K(x, f) satisfies the condition A then f(x) is ACL.

关键词： Quasiconformal mappings ACL-property Homeomorphism

On the Compactness of Homeomorphisms with Integrable Dilatations

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Acta Mathematica Sinica,English Series 1998年第2期14卷 161-168页

作者： Fang Ainong (department of mathematics,shanghai jiao tong university,shanghai 200030,china) department of mathematics Shanghai Jiao Tong University 200030 Shanghai China

In this paper,a distortion theorem and some equicontinuity and compactness theorems are obtained for the homeomorphism f with the sphere dilatation H（x,f）∈Lloc（D）.

关键词： Quasiconformal mappings Distortion theorem Compactness μ-homeomorphism

Traveling－Wave　Electrooptical　Modulator　on　Polymeric　Film　with　Reversal　Poling　Structure

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Chinese Journal of Lasers 1994年第1期B3卷 57-61页

作者： ZHOU Yi CHEN Yixin(department of Applied Physics, shanghai jiao tong university, shanghai200030, china)SUN Shiping(department of Electronical Engineering ,shanghai jiao tong university , shanghai 200052, china) shanghai jiaotong Univ Shanghai China

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Ｔｒａｖｅｌｉｎｇ－ＷａｖｅＥｌｅｃｔｒｏｏｐｔｉｃａｌＭｏｄｕｌａｔｏｒｏｎＰｏｌｙｍｅｒｉｃＦｉｌｍｗｉｔｈＲｅｖｅｒｓａｌＰｏｌｉｎｇＳｔｒｕｃｔｕｒｅ￥ＺＨＯＵＹｉ；ＣＨＥＮＹｉｘｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＡｐｐｌｉｅｄＰｈｙｓｉｃｓ，Ｓ...

关键词： reversal poling Electrooptical effect modulator

Martensitic Transformation in Fe-Mn-Si Based Shape Memory Alloys

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Journal of Materials Science & Technology 1999年第2期15卷 111-116页

作者： T. Y. Hsu (XU Zuyao)(shanghai jiao tong university, shanghai 200030, china) shanghai jiao tong university Shanghai 200030 China Chinese Academy of Sciences China

The critical driving force for martensitic transformation fcc ( gamma ) yields hcp ( epsilon ) in ternary Fe-Mn-Si alloys increases with the content of Mn and decreases with that of Si. Thermodynamical prediction of M//s in ternary Fe-Mn-Si alloys was established. The fcc ( gamma ) yields hcp ( epsilon ) martensitic transformation in Fe-Mn-Si is a semi-thermoelastic and the nucleation process does not strongly depend on soft mode. Nucleation occurs directly through an overlapping of stacking fault rather than pole mechanism, and it is suggested that stacking fault energy (SFE) is the main factor controlling nucleation. Based on the phenomenological theory of martensite crystallography, a shuffle on (0001)//h//c//p plane is required when d//1//1//1 does not equal d//0//0//0//2. The derived principal strain in Bain distortion is smaller, i, e., more reasonable than the values given by Christian. Alloying elements strengthening the austenite, lowering SFE of gamma phase and reducing T//N** gamma temperature may be beneficial to shape memory effect of Fe-Mn-Si based alloys. Accordingly, Fe-Mn-Si-RE and Fe-Mn-Si-Cr-N (or Fe-Mn-Si-Ni-Cr-N) are worthy to be recommended as shape memory materials with improved shape memory effect. (Edited author abstract) 48 Refs.

关键词： Mn Martensitic Transformation in Fe-Mn-Si Based Shape Memory Alloys Fe Si

A lumped mass finite element method for vibration analysis of elastic plate-plate structures

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Science china mathematics 2010年第6期53卷 1453-1474页

作者： LAI JunJiang1,HUANG JianGuo2,3,& SHI ZhongCi4 1department of mathematics,Minjiang university,Fuzhou 350108,china 2department of mathematics,shanghai jiao tong university,shanghai 200240,china 3Division of Computational Science,E-Institute of shanghai Universities,shanghai Normal university,shanghai 200234,china 4Institute of Computational mathematics,Academy of mathematics and Systems Science,Chinese Academy of Sciences,Beijing 100190,china 1. department of mathematics Minjiang University Fuzhou 350108 China2. Department of Mathematics Shanghai Jiao Tong University Shanghai 200240 China3. Division of Computational Science E-Institute of Shanghai Universities Shanghai Normal University Shanghai 200234 China4. Institute of Computational Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

The fully discrete lumped mass finite element method is proposed for vibration analysis of elastic plate-plate *** the space directions,the longitudinal displacements on plates are discretized by conforming linear elements,and the transverse displacements are discretized by the Morley *** means of the second order central difference for discretizing the time derivative and the technique of lumped masses,a fully discrete lumped mass finite element method is obtained,and two approaches to choosing the initial functions are also *** error analysis for the method in the energy norm is established,and some numerical examples are included to validate the theoretical analysis.

关键词： vibration analysis plate-plate structures lumped mass FEM error analysis

PROPERTIES OF NATURAL CAVITATION FLOWS AROUND A 2-D WEDGE IN SHALLOW WATER

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Journal of Hydrodynamics 2011年第6期23卷 730-736页

作者： CHEN Xin LU Chuan-jing LI Jie CHEN Ying department of Engineering Mechanics Shanghai Jiao Tong University Shanghai 200240 China department of Engineering Mechanics and State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai 200240 China

When a body navigates with cavity in shallow water, both flexible free surface and rigid bottom wall will produce great influences on the cavity shape and hydrodynamic performances, and further affect the motion attitude and stability of the body. In the present work, characteristics of the natural cavitating flow around a 2-D symmetrical wedge in shallow water were investigated and the influences of two type boundaries on the flow pattern were analyzed. The Volume Of Fluid （VOF） multiphase flow method which is suitable for free surface problems was utilized, coupled with a natural cavitation model to deal with the mass-transfer process between liquid and vapor phases. Within the range of the cavitation number for computation （0.07-1.81）, the cavity configurations would be divided into three types, viz., stable type, transition type and wake-vortex type. In this article, the shapes of the free surface and the cavity surface, and the hydrodynamic performance of the wedge were discussed under the conditions of relatively small cavitation number （〈0.256）. The present numerical cavity lengths generally accord with experimental data. When the cavitation number was decreased, the cavity was found to become longer and thicker, and the scope of the deformation of the free surface also gradually extends. The free surface and the upper cavity surface correspond fairly to their shapes. However, the lower side of the cavity surface was rather leveled due to the influence of wall boundary. The lift and drag coefficients of this 2-D wedge basically keep linear relations with the natural cavitation number smaller than 0.157, whereas direct proportion for drag and inverse proportion for lift.

关键词： shallow water natural cavitation boundary effect multiphase flow

MODELLING OF P/M FORMING PROCESSES BY FEM

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中国有色金属学会会刊：英文版 1995年第3期5卷 66-70页

作者： Wei, Yuanping Ruan, Xueyu(department of Plasticity Technology,shanghai jiao tong university, shanghai 200030) shanghai jiao tong Univ Shanghai China

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关键词： modelling P/M forming FEM yield criteria constitutive