检索结果-南通市图书馆

An interpolating boundary element-free method (IBEFM) for elasticity problems

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,mechanics & Astronomy) 2010年第4期53卷 758-766页

作者： REN HongPing 1 , CHENG YuMin 2 & ZHANG Wu 1 1 School of Computer Engineering and Science, shanghai university, shanghai 200072, china 2 shanghai Institute of Applied Mathematics and mechanics, shanghai university, shanghai 200072, china 1. School of Computer Engineering and Science Shanghai University Shanghai 200072 China2. Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China

The paper begins by discussing the interpolating moving least-squares (IMLS) method. Then the formulae of the IMLS method obtained by Lancaster are revised. On the basis of the boundary element-free method (BEFM), combining the boundary integral equation method with the IMLS method improved in this paper, the interpolating boundary element-free method (IBEFM) for two-dimensional elasticity problems is presented, and the corresponding formulae of the IBEFM for two-dimensional elasticity problems are obtained. In the IMLS method in this paper, the shape function satisfies the property of Kronecker δ function, and then in the IBEFM the boundary conditions can be applied directly and easily. The IBEFM is a direct meshless boundary integral equation method in which the basic unknown quantity is the real solution to the nodal variables. Thus it gives a greater computational precision. Numerical examples are presented to demonstrate the method.

关键词： moving least-squares (MLS) approximation interpolating moving least-squares (IMLS) method boundary integral equation meshless method boundary element-free method (BEFM) interpolating boundary element-free method (IBEFM) elasticity problem

A NONLINEAR THERMOCAPILLARY MIGRATION OF DROPLETS DUE TO DEPENDENCE OF PHYSICAL PROPERTIES ON TEMPERATURE

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2006年第4期18卷 469-474页

作者： SUN Ren department of Engineering mechanics Shanghai Jiaotong University Shanghai 200240 China

A slow thermocapillary migration of a droplet at vanishingly small Reynolds and Marangoni numbers was theoretically investigated. A force on the droplet released in another liquid subjected to arbitrary configuration of the gravitational field and an imposed thermal gradient for the case of constant liquid properties was derived using the general solutions given by Lamb. A solution to the migration was thereby obtained, which corresponds to the well-known YGB result as t →∞. In the case of variable physical properties with temperature, a nonlinear migration of the droplet was described by the dynamical equation of motion, and the numerical results were compared with available experimental data. The comparison exhibits a reasonable agreement between the theoretical prediction and the experimental results, which shows the dependence of physical properties on temperature is a primary cause of the continuous velocity variation in the thermocapillary droplet migration.

关键词： thermocapillary migration droplet/bubble dynamics interfacial tension thermal gradient

An Approximate Solution Technique Depending on an Artificial Parameter: A Special Example

在线全文

学校读者我要写书评

暂无评论

Communications in Nonlinear Science and Numerical Simulation 1998年第2期3卷 40-45页

作者： Jihuan HE (shanghai university, shanghai Institute of Applied Mathematics and mechanics, shanghai 200072, china) shanghai university Shanghai Institute of Applied Mathematics and Mechanics Shanghai 200072 China

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｈｅｌａｓｔｔｗｏｄｅｃａｄｅｓｗｉｔｈｔｈｅｒａｐｉｄｄｅｖｅｌｏｐｍｅｎｔｏｆｎｏｎｌｉｎｅａｒｓｃｉｅｎｃｅ，ｔｈｅｒｅｈａｓａｐｐｅａｒｅｄｅｖｅｒｉｎｃｒｅａｓｉｎｇｉｎｔ... 详细信息

ＩｎｔｒｏｄｕｃｔｉｏｎＩｎｔｈｅｌａｓｔｔｗｏｄｅｃａｄｅｓｗｉｔｈｔｈｅｒａｐｉｄｄｅｖｅｌｏｐｍｅｎｔｏｆｎｏｎｌｉｎｅａｒｓｃｉｅｎｃｅ，ｔｈｅｒｅｈａｓａｐｐｅａｒｅｄｅｖｅｒｉｎｃｒｅａｓｉｎｇｉｎｔｅｒｅｓｔｏｆｓｃｉｅｎｔｉｓｔｓ...

关键词： perturbation methods homotopy Duffing equation nonlinearity

Variational Iteration Method for Delay Differential Equations

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Communications in Nonlinear Science and Numerical Simulation 1997年第4期2卷 235-236页

作者： Jihuan HE (shanghai university,shanghai Institute of Applied Mathematics and mechanics,shanghai 2 0 0 0 72 ,china) shanghai university Shanghai Institute of Applied Mathematics and Mechanics Shanghai 200072 China

The variational iteration method is shown to be applicable to delay differential equations for analytical approximate solutions

关键词： Variational Iteration Method for Delay Differential Equations

On the generalized Busemann-Petty problem

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Mathematics 2007年第8期50卷 1103-1116页

作者： Song-jun L~(1,2+) Gang-song LENG~1 1.College of Mathematics and Computer Science,Chongqing Normal university,Chongqin 400047,china 2.department of Mathematics,shanghai university,shanghai 2.0444,china College of Mathematics Computer Science Chongqing Normal University Chongqin 400047 China department of Mathematics Shanghai University Shanghai 200444 China

The generalized Busemann-Petty problem asks whether the origin-symmetric convex bodies in ? n with a larger volume of all i-dimensional sections necessarily have a larger volume. As proved by Bourgain and Zhang, the answer to this question is negative if i > 3. The problem is still open for i = 2, 3. In this article we prove two specific affirmative answers to the generalized Busemann-Petty problem if the body with a smaller i-dimensional volume belongs to given classes. Our results generalize Zhang’s specific affirmative answer to the generalized Busemann-Petty problem.

关键词： star body cross i-section dual mixed volume Radon transform 52A30 52A40

FREE-SURFACE WAVES AND FAR WAKES GENERATED BY A FLOATING BODY IN A VISCOUS FLUID

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2003年第4期15卷 10-16页

作者： Lu Dong-qiang department of Mechanical Engineering, The university of Hong Kong, Hong Kong, china shanghai Institute of Applied Mathematics and mechanics, shanghai university, shanghai 200072, china department of Mechanical Engineering The University of Hong Kong Hong Kong China shanghai Institute of Applied Mathematics and mechanics Shanghai University Shanghai 200072 China

The free-surface waves and the flow field due to a body moving on the surfaceof an incompressible viscous fluid of infinite depth were studied analytically. The floating bodywas modeled as a normal point pressure on the free surface. Based on the Oseen approximation forgoverning equations and the linearity assumption for boundary conditions, the exact solutions inintegral form for the free-surface elevation, the velocities and the pressure were given. Byemploying Lighthill's two-stage scheme, the asymptotic representations in far field for largeReynolds numbers were derived explicitly. The effect of viscosity on the wave profiles was expressedby an exponential decay factor, which removes the singular behavior predicted by the potentialtheory.

关键词： free-surface waves velocity distribution floating body viscosity asymptotic representation light-hill's two-stage scheme

GURTIN VARIATIONAL PRINCIPLE AND FINITE ELEMENT SIMULATION FOR DYNAMICAL PROBLEMS OF FLUID-SATURATED POROUS MEDIA

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2003年第1期16卷 24-32页

作者： Yang Xiao Cheng Changjun department o,f mechanics, shanghai Institute of Applied Mathematics and mechanics,shanghai university,shanghai 200436,china) department of mechanics Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200436 China

Based on the theory of porous media, a general Gurtin variational principle for the initial boundary value problem of dynamical response of fluid-saturated elastic porous media is developed by assuming infinitesimal deformation and incompressible constituents of the solid and fluid phase. The finite element formulation based on this variational principle is also derived. As the functional of the variational principle is a spatial integral of the convolution formulation, the general finite element discretization in space results in symmetrical differential-integral equations in the time domain. In some situations, the differential-integral equations can be reduced to symmetrical differential equations and, as a numerical example, it is employed to analyze the reflection of one-dimensional longitudinal wave in a fluid-saturated porous solid. The numerical results can provide further understanding of the wave propagation in porous media.

关键词： saturated porous media Gurtin variational principle finite element method longitudinal wave

A study of mechanical behavior of rock-fill materials with reference to particle crushing

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2007年第z1期50卷 125-135页

作者： HUANG WenXiong1?, REN QingWen1 & SUN DeAn2 1 department of Engineering mechanics, Hohai university, Nanjing 210098, china 2.department of Civil Engineering, shanghai university, shanghai 200072, china department of Engineering mechanics Hohai University Nanjing 210098 China department of Civil Engineering Shanghai University Shanghai 200072 China

In rock-fill dams of 200 to 300 m high, maximum compressive stress can exceed 6 MPa. At such a high stress level, rock-fill materials may experience particle crushing during shear. The material behavior is highly sophisticated exhibiting pressure and density dependency as well as particle crushing effects. Through scrutinizing the relevant experimental data on rock-fill materials and sands published in the literatures, this paper is focused on understanding basic mechanical characteristics of this sort of materials in the light of constitutive modelling.

关键词： rock-fill materials granular materials compressibility shear dilatancy particle crushing

CURVILINEAR PATHS AND TRUST REGION METHODS WITH NONMONOTONIC BACK TRACKING TECHNIQUE FOR UNCONSTRAINED OPTIMIZATION

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2001年第3期19卷 241-258页

作者： De-tong Zhu (department of Mathematics, shanghai Normal university, shanghai 200234, china) 上海师范大学上海 200234

Focuses on a study which examined the modification of type approximate trust region methods via two curvilinear paths for unconstrained optimization. Properties of the curvilinear paths; Description of a method which combines line search technique with an approximate trust region algorithm; Information on the convergence analysis; Details on the numerical experiments.

关键词： curvilinear paths trust region methods nonmonotonic technique unconstrained optimization