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Nonlinear constitutive law for ferroelectric/ferroelastic material and its finite element realization

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Science china(Physics,mechanics & Astronomy) 2007年第1期50卷 70-86页

作者： LI YaoChen Department of Aerospace Engineering and applied mechanics,Tongji university,{3. 200092,china Department of Aerospace Engineering and applied mechanics Tongji UniversityShanghai 200092 China

The hysteresis phenomena of ferroelectric/ferroelastic material in polarization procedure are investigated. Some assumptions are presented based on the published experimental data. The electrical yielding criterion, mechanical yielding criterion and isotropic hardening model are established. The flow theory in incremental forms in polarization procedure is presented. The nonlinear constitutive law for electrical-mechanical coupling is proposed phenomenologically. Finally, the nonlinear constitutive law expressed in a form of matrices and vectors, which is immediately associated with finite element analysis, is formulated. In the example problem of a rectangular specimen subjected to a uniaxial electric field, the procedure from virgin state to fully polarized state is simulated. Afterward, a uniaxial compressive loading is applied to depolarizing the specimen. Results are in agreement with the experimental data.

关键词： ferroelectric/ferroelastic material constitutive law nonlinear finite element method.

Transverse patterns and spatiotemporal instability of a photorefractive oscillator

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Chinese Science Bulletin 1997年第9期42卷 724-729页

作者： ZHUANG Jun and TAN Weihan1. shanghai Institute of Optics and Fine mechanics, Chinese Academy of Sciences, shanghai 201800,{3. 2. shanghai university, shanghai 201800,{3. shanghai Institute of Optics and Fine mechanics Chinese Academy of Sciences Shanghai China shanghai university Shanghai China

IN time realm,instability and chaos phenomena of a nonlinear optical system have been dis-cussed *** recent years,as much interest was attracted to the transverse ef-fects in nonlinear optics,the study was developed t... 详细信息

关键词： photorefractive oscillator spatiotemporal instability transverse patterns.

ON UNIFORM ASYMPTOTIC STABILITY OF INFINITE DELAY DIFFERENCE EQUATIONS

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Chinese Annals of mathematics,Series B 2001年第4期22卷 495-502页

作者： ZHANG SHUNIAN Department of applied mathematics, shanghai Jiaotong {3. shanghai 20003., china. E-mail: snzhang@*** Department of applied mathematics Shanghai Jiaotong University Shanghai 200030 China

For the infinite delay difference equations of the general form, two new uniform asymptotic stability criteria are established in terms of the discrete Liapunov functionals.

关键词： Infinite delay difference equations Uniform asymptotic stability g-uniform asymptotic stability Discrete Liapunov functionals

Influence of Mo on the microstructure and mechanical properties of TiC-based cermets

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Rare Metals 2010年第4期29卷 346-350页

作者： WANG Xingqing,HE Xiaoxiang,and GUO Hailiang School of Materials Science and Engineering,shanghai university,shanghai 200072,china School of Materials Science and Engineering Shanghai University Shanghai China

The microstructures and mechanics properties of TiC-based cermets composed of TiC, WC, Ni, Co, Mo, and Cr3.2 were investigated. The results show that Mo has a great effect on the sintering densification, microstructures, and mechanical properties. The microstructures and distribution of Mo and Ti in the TiC-based cermets were analyzed. It was indicated that a new phase with Ti, Mo, W, and C was formed on the rim of （Ti,W）C grains by means of an addition of Mo into the TiC-based cermets. The new phase with a surrounding structure was of great aid to improve the wettability of the liquid phase on the solid phase surface of TiC, decrease the porosity and refine the grains of the hard phase, which gave rise to the increase in strength and hardness. The properties of the TiC-based cermets could be further improved to some extent by adding WC, Cr2C3. and Co.

关键词： TiC-based cermets Mo effect sintering densification microstructure mechanical properties

A MULTI-GRID ALGORITHM FOR STOKES PROBLEM

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Journal of Computational mathematics 1995年第4期13卷 291-305页

作者： Z. Huang(Department of applied mathematics, Tongji university, {3., china) TONGJI UNIV DEPT MATH APPLSHANGHAI 200092PEOPLES R CHINA

In this paper we describe a multi-grid algorithm for the penalty procedure of Stokes problem. It is proved that the convergence rate df the algorithm is bounded away from 1 independently of the meshsize. For convenien... 详细信息

关键词： Math Grid ED EH Bank

EXPERIMENTAL INVESTIGATIONS ON LONGITUDINAL DISPERSION CHARACTERISTICS OF TIDAL RIVERS

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Journal of Hydrodynamics 2003年第2期15卷 89-94页

作者： Fan Jing yu, Wang Dao zeng, Zhong Bao chang shanghai Institute of applied mathematics and {3., shanghai university, shanghai 200072, china shanghai Institute of applied mathematics and {3. Shanghai University Shanghai 200072 China

The longitudinal dispersion characteristics of tidal rivers areexperimentally investigated in a water channel. The longitudinal dispersion features and influentialfactors on pollutant in various stages of a tidal period in natural rivers are studied; the valueranges and variation trends of the longitudinal dispersion coefficient are obtained by means ofconcentration measurement. The results can provide important parameters for establishing the waterquality mathematical models in tidal rivers.

关键词： tidal river diffusion longitudinal dispersion coefficient

PDA MEASUREMENTS OF TWO-PHASE FLOW STRUCTURE AND PARTICLE DISPERSION FOR A PARTICLE-LADEN JET IN CROSSFLOW

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Journal of Hydrodynamics 2010年第1期22卷 9-18页

作者： FAN Jing-yu XU Song-li WANG Dao-zeng shanghai Institute of applied mathematics and {3. Shanghai University Shanghai 200072 China

The two-phase flow structure and particle dispersion for a dilute particle-laden jet in crossflow （JICF） were experimentally investigated by means of Phase Doppler Anemometry （PDA） measurement. The two-phase flow experiments were conducted for different flow conditions and solid particle parameters, including the ratio of the jet velocity to crossflow velocity, the particle size and mass loading. The experimental results indicate that the fine particles with the size of 70 micron and the mass loading of 0.05% have a minor influence on the mean and fluctuation velocity fields of the two-phase JICF. However, the fine particle transport by the two-phase JICF is dominantly and preferentially affected by the shear layer vortices and exhibits a somewhat enhanced dispersion as compared to the fluid. For the coarse particles with the particle size ranging from 3.0 micron to 700 micron and the mass loading less than 0.16%, the effect of the particle parameters on the fluid phase is associated with both the anisotropic properties of the flow field and the trajectory deviation of the settling particles from the fluid. Compared to the single-phase JICF, the two-phase JICF laden with the coarse particles is recognized to possess more pronounced mean velocity alteration and turbulence modulation of the fluid phase in the presence of the particles with the larger particle size and higher mass loading.

关键词： jet crossflow two-phase flow structure particle dispersion Phase Doppler Anemometry (PDA) measurement

AN INTEGRAL EQUATION DESCRIBING RIDING WAVES IN SHALLOW WATER OF FINITE DEPTH

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Journal of Hydrodynamics 2003年第5期15卷 70-74页

作者： An Shu ping, Le Jia chun, Dai Shi qiang shanghai Institute of applied mathematics and {3., shanghai university, shanghai 200072, china shanghai Institute of applied mathematics and {3. Shanghai University Shanghai 200072 China

An integral equation describing riding waves, i. e. , small-scaleperturbation waves superposed on unperturbed surface waves, in shallow water of finite depth wasstudied via explicit Hamiltonian formulation, and the water was regarded as ideal incompressiblefluid of uniform density. The kinetic energy, density of the perturbed fluid motion was formulatedwith Hamiltonian canonical variables, elevation of the free surface and the velocity potential atthe free surface. Then the variables were expanded to the first order at the free surface ofunperturbed waves. An integal equation for velocity potential of perturbed waves on the unperturbedfree surface was derived by conformal mapping and the Fourier transformation. The integral equationcould replace the Hamiltonian canonical equations which are difficult to solve. An explicitexpression of Lagrangian density function could be obtained by solving the integral equation. Themethod used in this paper provides a new path to study the Hamiltonian formulation of riding wavesand wave interaction problems.

关键词： surface waves water of finite depth hamiltonian formulation riding waves integral equation wave interaction

Multiple Shock Fronts for Hyperbolic Conservation Laws in Higher Dimensional Space

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Acta Mathematica Sinica,English Series 1995年第1期11卷 88-104页

作者： Wang Yaguang Department of applied mathematics shanghai Jiao Tong {3. shanghai,20003. china shanghai Jiao Tong university

The local existence of multiple shock fronts for hyperbolic conservation laws in higher dimensional space is established under the assumption that its frozen problem produces multiple uniformly stable planar shock fro... 详细信息

关键词： Laws Multiple Shock Fronts for Hyperbolic Conservation Laws in Higher Dimensional Space 几几 Math