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STABILITY OF IMPULSIVE LINEAR HYBRID SYSTEMS WITH TIME DELAY

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Journal of Systems Science & Complexity 2010年第4期23卷 738-747页

作者： Yu ZHANG·Jitao SUN department of Mathematics,Tongji university,shanghai 200092,china. JitaoSUN department of Mathematics Tongji University

This paper investigates the stability of impulsive linear hybrid systems with time *** a number of delay-independent/delay-dependent stability criteria are obtained by using Lyapunovfunctions or Lyapunov *** examples ... 详细信息

关键词： Impulsive linear hybrid system Lyapunov function Lyapunov functional time delay.

The Effect of Material Properties on StressState Near the Ply Interface of Laminates

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Communications in Nonlinear Science and Numerical Simulation 1999年第2期4卷 118-122页

作者： Wei FENG(Institute of Applied Mathematics and mechanics, shanghai university, shanghai 200072,china)E-mail: glliu@*** Institute of Applied Mathematics and mechanics Shanghai University Shanghai 200072 China

In this paper, the attention is restricted to the cases of symmetric angleply laminates. The stress distributions are studied at the ply level with an emphasison the interface effect in the central region of symmetric composite laminates. It hasbeen discovered that the numerical distributions of stresses in angle-ply laminates arequite different from the results by the classical laminate theory. There are in-plane stressconcentrations near ply interface in the interior region of laminated composites due to theabrupt change of fiber orientation. Because interlaminar stresses and thus delaminationcan arise in any gradient stress field in a laminated composite, there exist interlaminarstresses near the ply interface in the interior region. The effects of the material propertieson the concentration of in-plane stress are also discussed.

关键词： laminate stress concentration material property

Macro-micromechanical approaches for non-coaxiality of coarse grained soils

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中国科学：技术科学英文版 2011年第S1期54卷 147-153页

作者： QIAN JianGu 1,2,HUANG MaoSong 1,2 & SUN HaiZhong 1,2 1 Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji university,shanghai 200092,china 2.department of Geotechnical Engineering,Tongji university,shanghai 200092,china 1. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji University Shanghai 200092 China2. Department of Geotechnical Engineering Tongji University Shanghai 200092 China

For coarse grained soils,their principal stress directions may change when the water level of embankment dam varies *** this loading case,the principal directions of stress and strain rate will become *** an effort to model non-coaxial behavior,a modified three-dimensional non-coaxial model is developed in the context of vertex yield(tangent plasticity) *** Element Method(PFC) incorporating user-defined interparticle contact models is also employed to gain an insight into microscopic mechanism of *** analysis focuses on non-coaxial behaviors under simple shear *** has been shown that the proposed non-coaxial model gives good predictions for non-coaxiality with reference to microscopic observations while the classical coaxial model fails to simulate the non-coaxial *** general,non-coaxiality as a result of the rotation of principal stress,is large at a small shear strain,and inclined to become negligible with increasing shear *** coarse grained soils,their non-coaxiality tends to largely depend on the initial normal pressure,where a larger degree of non-coaxiality can be observed at a higher pressure.

关键词： coarse grained soils non-coaxiality particle flow code simple shear

NUMERICAL SIMULATION OF MORPHOLOGY OF POLYMER CHAIN COILS IN COMPLEX FLOWS

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Chinese Journal of Polymer Science 2005年第5期23卷 453-462页

作者： Hong Zheng Wei Yu Chi-xing Zhou department of Polymer Materials Science & Engineering,shanghai Jiaotong university,shanghai 200240,china shanghai Jiao Tong Univ Dept Polymer Mat Sci & Engn Shanghai 200240 Peoples R China

A new coupled finite element formulation is proposed to calculate a conformation tensor model in two complex flows： a planar contraction flow and a planar flow around a symmetrically placed cylinder. The components of conformation tensor are first computed together with the velocity and pressure to describe the change of morphology of polymer chain coils in flow fields. Macroscopic quantities of viscoelastic flow are then calculated based on the conformation tensor. Comparisons between the numerical simulations and experiments for stress patterns and velocity profiles are carried out to prove the validity of the method.

关键词： Viscoelastic flow Morphology Complex flows Conformation tensor model Finite element method (FEM).

ON NON-ISOTROPIC JACOBI PSEUDOSPECTRAL METHOD

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Journal of Computational Mathematics 2008年第4期26卷 511-535页

作者： Benyu Guo Keji Zhang department of Mathematics,shanghai Normal university,shanghai 200234,china Scientific Computing Key Laboratory of shanghai Universities Division of Computational Science of E-Institute of shanghai Universities department of Mathematics Shanghai Normal University Shanghai 200234

In this paper, a non-isotropic Jacobi pseudospectral method is proposed and its appli- cations are considered. Some results on the multi-dimensional Jacobi-Gauss type interpolation and the related Bernstein-Jackson type inequalities are established, which play an important role in pseudospectral method. The pseudospectral method is applied to a twodimensional singular problem and a problem on axisymmetric domain. The convergence of proposed schemes is established. Numerical results demonstrate the efficiency of the proposed method.

关键词： Jacobi pseudospectral method in multiple dimensions Jacobi-Gauss type inter-polation Bernstein-Jackson type inequalities Singular problem Problem on axisymmetricdomain.

Currents induced by vertical varied radiation stress in standing waves and evolution of the bed composed of fine sediments

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International Journal of Sediment Research 2009年第2期24卷 214-226页

作者： Jing-Xin ZHANG1 and Hua LIU21 Lecturer,department of Engineering mechanics,School of Naval Architecture,Ocean and Civil Engineering,shanghai Jiao Tong university,800 Dongchuan Road,shanghai 200240,china 2.department of Engineering mechanics,School of Naval Architecture,Ocean and Civil Engineering,shanghai Jiao Tong university,800 Dongchuan Road,shanghai 200240,china [a]department of Engineering mechanics School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China [b]Department of Engineering Mechanics School of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University 800 Dongchuan Road Shanghai 200240 China

This paper extends the conventional concept of radiation stress(Longuet-Higgins and Stewart,1964) in progressive water waves to standing waves,so that its vertical profile could be defined and calculated in a new technical way. The hydrodynamic numerical model being coupled with the vertically varying radiation stress in standing waves is used to simulate the currents being induced by standing waves in the vertical section. Numerical modeling of suspended sediment transport is then carried out to simulate the evolution of the bed composed of fine sediments by the currents. The scour and deposition patterns simulated are in qualitative agreement with prior laboratory and field observations.

关键词： Standing wave Vertical variation in radiation stress Scour pattern Suspended sediment

TURBULENT MIXING AND EVOLUTION IN A STABLY STRATIFIED FLOW WITH A TEMPERATURE STEP

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Journal of Hydrodynamics 2009年第1期21卷 84-92页

作者： QIU Xiang ZHANG Dao-xiang LU Zhi-ming LIU Yu-lu shanghai Institute of Applied Mathematics and mechanics Shanghai University Shanghai 200072 China department of Mathematics Shanghai University Shanghai 200444 China

Large-Eddy Simulation （LES） is applied to examine the turbulent mixing and evolution in a stably stratified flow with a thermally sharp interface. Turbulent velocity intensities and turbulent kinetic energy are analyzed by considering the mean shear and stratification effects. The evolution of turbulent mixing layer and turbulent structures are mainly investigated. The results show that the streamwise intensities are much larger than the vertical intensities, and vertical fluctuations decay more rapidly at the presence of stratification. The qualitatively computational results suggest that the mixing layer, defined by the mean temperature, inclines to the side with small inlet velocity. The evolution of the half-width of the mixing layer shows two different slopes. The turbulent structure with high vorticity is restricted in the mixing layer especially in strong stratified cases.

关键词： stratified turbulence turbulent mixing turbulent structure Large-Eddy Simulation (LES)

Application of Petri Net to Fault Diagnosis in Satellite

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Journal of Systems Engineering and Electronics 2001年第2期12卷 92-96页

作者： Ding Caihong School of mechanics, DongHua university, shanghai 200051, P R. china School of mechanics DongHua University Shanghai 200051 P. R. China

A prototype of fault diagnosis based on Petri net, which is developed for a satellite tele-control subsystem, is introduced in this paper. Its structure is first given with the emphasis on a Petri net modeling tool which is designed using the object oriented method. The prototype is connected to the database with DAO (Date Access Object) technique, and makes the Petri net's firing mechanism and its analyzing methods to be packed up as DLL (Dynamic Link Library) documents. Compared with the rule-based expert system method, the Petri net-based one can store the knowledge in mathematical matrix and make inference more quickly and effectively.

关键词： Database systems Expert systems Matrix algebra Object oriented programming Petri nets Software prototyping

Data fusion for target tracking in wireless sensor networks using quantized innovations and Kalman filtering

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Science china(Information Sciences) 2012年第3期55卷 530-544页

作者： XU Jian1,2 , LI JianXun1,2 & XU Sheng3 1department of Automation, Science and Technology on Avionics Integration Laboratory, shanghai Jiao Tong university, shanghai 200240, china 2department of Automation, System Control and Information Processing, Ministry of Education of china, shanghai Jiao Tong university, shanghai 200240, china 3School of Mechanical Engineering, shanghai Jiao Tong university, shanghai 200240, china 1. department of Automation Science and Technology on Avionics Integration Laboratory Shanghai Jiao Tong University Shanghai 200240 China2. Department of Automation System Control and Information Processing Ministry of Education of China Shanghai Jiao Tong University Shanghai 200240 China3. School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China

A novel networked data-fusion method is developed for the target tracking in wireless sensor networks (WSNs). Specifically, this paper investigates data fusion scheme under the communication constraint between the fusion center and each sensor. Such a message constraint is motivated by the bandwidth limitation of the communication links, fusion center, and by the limited power budget of local sensors. In the proposed scheme, each sensor collects one noise-corrupted sample, performs a quantizing operation, and transmits quantized message to the fusion center. Then the fusion center combines the received quantized messages to produce a final estimate. The novel data-fusion method is based on the quantized measurement innovations and decentralized Kalman filtering (DKF) with feedback. For the proposed algorithm, the performance analysis of the estimation precision is provided. Finally, Monte Carlo simulations show the effectiveness of the proposed scheme.

关键词： data fusion target tracking limited bandwidth quantized innovation Kalman filtering