广义Boussinesq方程的多辛方法

广义Boussinesq方程作为一类重要的非线性方程有着许多有趣的性质,基于Hamilton空间体系的多辛理论研究了广义Boussinesq方程的数值解法,构造了一种等价于多辛Box格式的新隐式多辛格式,该格式满足多辛守恒律、局部能量守恒律和局部动量守恒律．对广义Boussinesq方程孤子解的数值模拟结果表明,该多辛离散格式具有较好的长时间数值稳定性．     

广义系统的Hamilton矩阵与H\-2代数Riccati方程的稳定化解

研究线性连续广义系统的Hamilton矩阵及H\-2代数Riccati方程.　提出一个标准的广义H\-2代数Riccati方程及对应的Hamilton矩阵，给出该Hamilton矩阵的几个重要性质. 在此基础上，得到该广义H\-2代数Riccati方程的稳定化解存在的一个充分条件并给出求解方法.此条件具有一般性, 主要定理是正常系统相应结果的推广.     

广义量子动力学理论中通常复数量子力学的Hamilton量表述

讨论广义量子动力学理论中,通常复数量子力学的Hamilton量表述。在引入总迹Lagrange量、总迹Hamilton量和两种类型的Poison括号运算之后,不仅能得到用Poisson括号表达的算子的总迹泛函的运动方程,还能得到用Poisson括号表达的部分算子的运动方程。由此得到广义量子动力学理论中用Poisson括号和总迹Hamilton量表达的通常复数量子力学的一组基本运动方程。并且这组方程和Heisenberg方程是相溶的。     

与含有三个位势矩阵谱问题相联系的非线性发展方程族及其Hamilton结构

从含有三个位势的4×4矩阵谱问题出发,导出两类非线性发展方程.然后利用迹公式,给出了这两类方程的广义Hamilton结构.     

带乘性噪声的空间分数阶随机非线性Schrödinger方程的广义多辛算法

带乘性噪声的空间分数阶随机非线性Schrödinger方程是一类重要的方程,可应用于描述开放非局部量子系统的演化过程.该方程为一个无穷维分数阶随机Hamilton系统,且具有广义多辛结构和质量守恒的性质.针对该方程的广义多辛形式,在空间上采用拟谱方法离散分数阶微分算子,在时间上则采用隐式中点格式,构造出一类保持全局质量的广义多辛格式.对行波解和平面波解等进行数值模拟,结果验证了所构造格式的有效性和保结构性质,时间均方收敛阶约在0.5到1之间.     

压电热弹性体的变分原理及正则方程和齐次方程

结合对偶变量理论,为压电热弹性体混合层合板问题推导了齐次的控制方程和Hamilton等参元列式．首先根据广义的Hamilton变分原理推导了压电热弹性体非齐次的Hamilton正则方程．然后进一步考虑了热平衡方程与导热方程中变量的对偶关系,通过增加正则方程的维数,成功地将非齐次的正则方程转化为能独立求解压电热弹性体耦合问题的齐次控制方程．为了推导四节点Hamilton等参元列式的方便,可将温度梯度关系类比成本构关系并构建新的变分原理．齐次方程大大简化了人们在分析压电热弹性体耦合问题时,通常要求解非齐次方程和关于平衡方程和导热方程的二阶微分方程的繁琐方法,同时也减少了数值计算工作量．     

一些数学物理问题中的Hamilton方程

讨论了新的一系列在数学物理方程中微分方程的Hamilton正则表示,其中包括变系数2阶对称方程的Hamilton系统,关于常系数的4阶对称方程新的非齐次Hamilton表示,MKdV方程以及KP方程的正则表示.     

梁振动方程的一种新解法

本运用广义差分法建立了梁振动方程一种新解法，井对其稳定性进行了讨论。     

梁振动方程的一种新解法

本文运用广义差分法建立了梁振动方程一种新解法，并对其稳定性进行了讨论     

水中悬浮隧道的空间曲线结构运动方程

借助参考直线坐标系,求解空间曲线结构在曲线坐标系中的几何方程．运用Hamilton原理推导空间螺旋曲线梁结构的运动方程．方程表明空间曲线结构4个自由度相互耦合,当结构退化为平面曲线结构时,两个相互垂直平面内的各自由度相互耦合．空间任意曲线梁结构的动力方程均可按照该文推导思路得出．对于水中悬浮隧道结构,可以忽略转动动能对振动的影响．     

边界剪力反馈下梁振动系统根子空间的完备性

讨论了一个在边界上有剪力反馈控制的Euler-Bernoulli梁方程，证明了其广义本征函数生成的根子空间在能量Hilbert空间中是完备的．     

Existence and Exponential Stability for a Euler-Bernoulli Beam Equation with Memory and Boundary Output Feedback Control Term

In this paper, we consider the Euler-Bernoulli beam equation with memory and boundary output feedback control term. We prove the existence of solutions using the Galerkin method and then investigate the exponential stability of solutions by using multiplier technique. This work was supported by grant number KRF-2005-202-C00030 from the Korea Research Foundation. This work was supported by National Institute for Mathematical Sciences.     

Generalized solutions for the Euler-Bernoulli model with distributional forces

We establish existence and uniqueness of generalized solutions to the initial-boundary value problem corresponding to an Euler-Bernoulli beam model from mechanics. The governing partial differential equation is of order four and involves discontinuous, and even distributional, coefficients and right-hand side. The general problem is solved by application of functional analytic techniques to obtain estimates for the solutions to regularized problems. Finally, we prove coherence properties and provide a regularity analysis of the generalized solution.     

Euler-Bernoulli梁在自激励边界反馈下的动力行为

考虑一端固定 ,一端在 van der Pol自激励边界反馈下 Euler-Bernoulli梁的动力行为 .首先设计梁方程的有限元离散格式 ,然后对选定的初始条件计算振动能量的终极变化 .数值结果表明 ,当反馈增益常数由小到大变化时 ,振动能量的变化经历慢周期 ,快周期 ,混沌 ,然后再回到周期振动的过程 .为进一步的理论研究提供了直观的数值表示 .     

Euler-Bernoulli beams from a symmetry standpoint-characterization of equivalent equations

We completely solve the equivalence problem for Euler-Bernoulli equation using Lie symmetry analysis. We show that the quotient of the symmetry Lie algebra of the Bernoulli equation by the infinite-dimensional Lie algebra spanned by solution symmetries is a representation of one of the following Lie algebras: 2A₁, A₁⊕A₂, 3A₁, or A3,3⊕A₁. Each quotient symmetry Lie algebra determines an equivalence class of Euler-Bernoulli equations. Save for the generic case corresponding to arbitrary lineal mass density and flexural rigidity, we characterize the elements of each class by giving a determined set of differential equations satisfied by physical parameters (lineal mass density and flexural rigidity). For each class, we provide a simple representative and we explicitly construct transformations that maps a class member to its representative. The maximally symmetric class described by the four-dimensional quotient symmetry Lie algebra A3,3⊕A₁ corresponds to Euler-Bernoulli equations homeomorphic to the uniform one (constant lineal mass density and flexural rigidity). We rigorously derive some non-trivial and non-uniform Euler-Bernoulli equations reducible to the uniform unit beam. Our models extend and emphasize the symmetry flavor of Gottlieb's iso-spectral beams [H.P.W. Gottlieb, Isospectral Euler-Bernoulli beam with continuous density and rigidity functions, Proc. R. Soc. Lond. Ser. A Math. Phys. Eng. Sci. 413 (1987) 235-250].     

ON THE NONLINEAR TIMOSHENKO-KIRCHHOFF BEAM EQUATION

6o.IntroductionThemainresultsofthispaperwerepresentedin[4l.Letusconsiderthetransversalvibrationsu(x,t)(o5x5L,t2o)ofahomogeneousbeam.Inthefollowing,thelettersp,E,G(resp.S,I,k)withdenotetheusualphysical(resp.geometrical)paJrametersofthebeam.Moreprecisely,p:=volumedensity,E:=Youngmodulusofelasticity,G:=shearmodulus,S:=areaofthecrosssection,I:=momentofinertiaofthecrosssection,R2:=IS-',kisapositivenumber51whichdependsupon'thegeometryofthecrosssection(see[62,2o]),e.g.forrectangularcrosssection…     

Boundary Controllability and Observability of a One-Dimensional Nonuniform SCOLE System

A hybrid system, composed of an elastic beam governed by an Euler-Bernoulli beam equation with variable coefficients and a linked rigid body governed by an ordinary differential equation, is considered. Various controllability/observability properties of the system under bounday control/observation are studied. It is shown that an open-loop smooth/singular controller of either torque control or force control is sufficient to make the system exactly controllable in arbitrarily short time duration. The work was carried out with the support of the National Natural Science Foundation of China and the Russian Foundation for Fundamental Researches, Grant 02-01-00554.     

On the spectrum of Euler-Bernoulli beam equation with Kelvin-Voigt damping

The spectral property of an Euler-Bernoulli beam equation with clamped boundary conditions and internal Kelvin-Voigt damping is considered. The essential spectrum of the system operator is rigorously identified to be an interval on the left real axis. Under some assumptions on the coefficients, it is shown that the essential spectrum contains continuous spectrum only, and the point spectrum consists of isolated eigenvalues of finite algebraic multiplicity. The asymptotic behavior of eigenvalues is presented.     

Techniques for approximating a spatially varying Euler-Bernoulli model with a constant coefficient model

Developing accurate models to describe the behaviour of a physical system often results in differential equations with spatially varying coefficients. A notable example of this that appears in many applications is the Euler-Bernoulli beam equation for transverse vibrations. This equation with spatially varying coefficients, such as when the bending stiffness or mass per unit length varies along the length of the beam, is of interest in the current research. Methods for approximating the Euler-Bernoulli equation with periodically varying coefficients have been proposed yet there is still a need for methods that approximate the more general, non-periodically varying, cases. The goal of this research is to obtain a constant coefficient Euler-Bernoulli equation that accurately approximates the original spatially varying equation using an inverse problem approach. Obtaining such an approximation has advantages in control applications where a constant coefficient model is strongly preferred for computational efficiency. The motivation for this research stems from previous work by the authors on modelling cable-harnessed structures. The spatially varying equation is solved using the Lindstedt-Poincaré perturbation method and these results are used to determine the approximate model. Multiple inverse problem methods for determining the coefficients in the approximate model are considered including metric minimization, the modal participation factor (MPF), and the proper orthogonal decomposition (POD). Continuous version of POD and MPF methods are obtained. Several wrapping patterns and boundary conditions are considered for comparison and the results are in good agreement with analytical and finite element analysis (FEA) results.     

动态控制下Euler-Bernoulli梁的多项式镇定

考虑动态输出反馈控制下Euler-Bernoulli梁的振动抑制问题,证明了系统算子生成的C0-半群,不指数稳定但渐近稳定.且当初值充分光滑时,利用Riesz基方法估计出系统能量多项式衰减.