检索结果-南通市图书馆

On two transverse nonlinear models of axially moving beams

在线全文

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2009年第3期52卷 743-751页

作者： DING Hu1 & CHEN LiQun1,2 1 shanghai Institute of Applied Mathematics and mechanics, shanghai university, shanghai 200072, china 2 department of mechanics, shanghai university, shanghai 200444, china shanghai Institute of Applied Mathematics and mechanics Shanghai University department of mechanics Shanghai University

Nonlinear models of transverse vibration of axially moving beams are computationally investigated. A partial-differential equation is derived from the governing equation of coupled planar motion by omit- ting its longitudinal terms. The model can be reduced to an integro-partial-differential equation by av- eraging the beam disturbed tension. Numerical schemes are respectively presented for the governing equations of coupled planar and the two governing equations of transverse motion via the finite dif- ference method and differential quadrature method under the fixed boundary and the simple support boundary. A steel beam and a copper beam are treated as examples to demonstrate the deviations of the solutions to the two transverse equations from the solution to the coupled equation. The numerical results indicate that the differences increase with the amplitude of vibration and the axial speed. Both models yield almost the same precision results for small amplitude vibration and the inte- gro-partial-differential equation gives better results for large amplitude vibration.

关键词： axially moving beam nonlinearity transverse vibration finite difference method differential quadrature method

Boundary element-free method for elastodynamics

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,mechanics & Astronomy) 2005年第6期48卷 641-657页

作者： CHENG Yumin1 & PENG Miaojuan2 1. shanghai Institute of Applied Mathematics and mechanics, shanghai university, shanghai 200072, china 2. department of Civil Engineering, shanghai university, shanghai 200072, china shanghai Institute of Applied Mathematics and mechanics Shanghai University Shanghai China department of Civil Engineering Shanghai University Shanghai China

The moving least-square approximation is discussed first. Sometimes the method can form an ill-conditioned equation system, and thus the solution cannot be obtained correctly. A Hilbert space is presented on which an orthogonal function system mixed a weight function is defined. Next the improved moving least-square approximation is discussed in detail. The improved method has higher computational efficiency and precision than the old method, and cannot form an ill-conditioned equation system. A boundary element-free method (BEFM) for elastodynamics problems is presented by combining the boundary integral equation method for elastodynamics and the improved moving least-square approximation. The boundary element-free method is a meshless method of boundary integral equation and is a direct numerical method compared with others, in which the basic unknowns are the real solutions of the nodal variables and the boundary conditions can be applied easily. The boundary element-free method has a higher computational efficiency and precision. In addition, the numerical procedure of the boundary element-free method for elastodynamics problems is presented in this paper. Finally, some numerical examples are given.

关键词： moving least-square approximation, improved moving least-square approximation, elastodynamics, boundary integral equation, meshless method, boundary element-free method, Fourier eigen transform.

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

The complex variable reproducing kernel particle method for elasto-plasticity problems

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(Physics,mechanics & Astronomy) 2010年第5期53卷 954-965页

作者： CHEN Li1 & CHENG YuMin2 1 department of Engineering mechanics,Chang’an university,Xi’an 710064,china 2 shanghai Institute of Applied Mathematics and mechanics,shanghai university,shanghai 200072,china department of Engineering mechanics Chang'an University Xi'an 710064 China

On the basis of reproducing kernel particle method(RKPM),using complex variable theory,the complex variable reproducing kernel particle method(CVRKPM) is discussed in this *** advantage of the CVRKPM is that the correction function of a two-dimensional problem is formed with one-dimensional basis function when the shape function is *** the CVRKPM is applied to solve two-dimensional elasto-plasticity *** Galerkin weak form is employed to obtain the discretized system equation,the penalty method is used to apply the essential boundary *** then,the CVRKPM for two-dimensional elasto-plasticity problems is formed,the corresponding formulae are obtained,and the Newton-Raphson method is used in the numerical *** numerical examples are given to show that this method in this paper is effective for elasto-plasticity analysis.

关键词： meshless method reproducing kernel particle method(RKPM) complex variable reproducing kernel particle method(CVRKPM) correction function elasto-plasticity

Optimal motion planning of an underactuated spacecraft using wavelet approximate method

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2006年第8期16卷 868-873页

作者： GE Xinsheng, CHEN Liqun and LIU Yanzhu (Beijing Institute of Machinery, Beijing 100085, china department of mechanics, shanghai university, shanghai 200072, china department of Engineering mechanics, shanghai Jiaotong university, shanghai 200030, china) Beijing Institute of Machinery Beijing 100085 China. department of mechanics Shanghai University Shanghai 200072 China. department of Engineering mechanics Shanghai Jiaotong University Shanghai 200030 China

An optimal motion planning scheme using wavelet approximation is proposed for an underactuated spacecraft. The motion planning of an underactuated spacecraft can be formulated as an optimal control of a drift-free system. A cost functional is used to incorporate the control energy and the final state errors. The motion planning is to determine control inputs to minimize the cost functional. Using the method of wavelet, one can transform an infinite-dimensional optimal control problem to a finite-dimensional one and use Gauss-Newton algorithm to solve it for a feasible trajectory which satisfies nonholonomic constraints. The proposed scheme has been applied to a rigid spacecraft with two momentum wheels. The numerical simulation results indicate that optimal control with wavelet approximation is an effective approach to steering an underactuated spacecraft system from the initial configuration to the final configuration.

关键词： underactuated spacecraft motion planning optimal control nonholonomic constraint wavelet analysis.

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

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(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 School of Computer Engineering and Science 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

Weakly nonlinear stability of ultra-thin slipping films

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第9期15卷 827-831页

作者： HU Guohui(shanghai Institute of Applied Mathematics and mechanics, shanghai university, shanghai 200072, china) shanghai Institute of Applied Mathematics and mechanics Shanghai University Shanghai 200072 China

A weakly nonlinear theory is presented to study the effects of slippage on the stability of the ultra-thin polymer films. The nonlinear mathematical model is constructed for perturbations of small finite amplitude based on hydrodynamic equations with the long wave approximation. Results reveal that the nonlinearity always accelerates the rupture of the films. The influences of the slip length, film thickness, and initial amplitude of perturbations on the rupture of the films are investigated.

关键词： ultra-thin film weakly nonlinear theory hydrodynamic stability rupture of thin film.

A New Cellular Automaton Model for TrafficFlow

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 1999年第4期4卷 264-267页

作者： Yongtao HU(shanghai institute of Applied Mathematics and mechanics, shanghai university,shanghai 200072, china) shanghai Institute of Applied Mathematics and mechanics Shanghai University Shanghai 200072 China

IntroductionCellularautomaton(CA)***,thesemodelSareremaxkable***]introdu... 详细信息

IntroductionCellularautomaton(CA)***,thesemodelSareremaxkable***]introdu...

关键词： traffic model transportation simulation cellular automata

Numerical Solution of Heat Tranfer Problemwith Flow and Solidification in Round BilletContinuous Casting of Steel

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 1999年第3期4卷 236-239页

作者： Jiahong GUO(shanghai Institute of Applied Mathematics and mechanics, shanghai university,shanghai 200072, china)Xin HONG(College of Material Science, shanghai university, shanghai 200072, china) shanghai Institute of Applied Mathematics and mechanics Shanghai University Shanghai 200072 China College of Material Science Shanghai University Shanghai 200072 China

IntroductionThetechnologyofc***g,***,itisimportallttostudythep... 详细信息

IntroductionThetechnologyofc***g,***,itisimportallttostudythep...

关键词： heat transfer flow and solidification round billet continuous casting