共查询到19条相似文献,搜索用时 109 毫秒
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双参数地基上Reissner板弯曲问题的边界积分方程 总被引:1,自引:0,他引:1
本应用广义函数的Fourier积分变换,导出了双参数地基上Reissner板弯曲问题的两个基本解。在此基础上,从虚功原理出发,依据胡海昌导出的Reissner板弯曲理论,推导出适用于任意形状,任意荷载,任意边界条件情形的三个边界积分方程,为边界元法在这一问题中的应用提供了理论基础。中给出了固支、简支、自由三类边界的算例,并与解析解比较,均得到满意的结果。 相似文献
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从广义函数论出发,本文引入一特殊广义函数δθ_P,通过它以及它的各阶导数建立了任一足够光滑函数的各阶导数的边界积分方程。对于由线性偏微分算子定义的问题,只要存在着相应的基本解,问题的偏微分方程总可转换成边界积分方程。 相似文献
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单位圆到任意曲线保角变换的近似计算方法 总被引:4,自引:0,他引:4
本文讨论了将单位圆内部映射成由任意曲线(包括任意曲线割缝)边界围成的单连通域内部或外部的保角变换问题.以多边形逼近单连通域的边界,采用Schwartz-Christoffel积分建立单位圆与该多边形的映射函数.给出了确定Schwartz-Christoffel积分中未知参数的数值计算方法. 相似文献
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在[1]的基础上,我们进一步应用可动边界的变分原理于固体体系的离散分析,得到有限元广义伽略金方程,边界变分方程,边界积分方程.这些方程描述了待解函数在元素内部与元素的边界上应满足的方程. 当对固体体系进行离散分析时,可以应用这些方程去建立不同情况下的求解待解函数的离散方程.亦可作为相应情况下的简化计算的依据. 由本文得到的边界积分方程可知,在[2]中提出的J积分形式,应用于内部元素边界的围道积分计算是不适宜的. 相似文献
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白噪声广义算子在白噪声分析理论及其应用中起着十分重要的作用.
本文主要讨论了白噪声广义算子值函数的积分及相关问题.
主要工作有: 引入了广义算子值测度的概念,
分别讨论了这种测度在象征和算子p-范数意义下的变差及相互关系;
借助于广义算子的Wick积运算,
引入了广义算子值函数关于广义算子值测度的一种积分---Bochner-Wick积分,
讨论了这种积分的性质, 建立了相应的收敛定理并且展示了其在量子白噪声理论中的应用;
探讨了Bochner-Wick积分的Fubini定理及相关问题. 相似文献
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在外微分的基础上讨论了多元函数积分号下凑微分、换元和分部积分问题,并得到了一种计算多元函数积分的统一方案:使用凑微分、换元和分部积分等手段将被积式变形成特定形式后应用广义Stokes公式,区域上的积分就能不断转化成边界上的积分,从而实现"降维".此方案中不必使用通常的化累次积分方法.所举计算实例演示了这些方法的可行性. 相似文献
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本文利用镜像法和直接积分导出了弹性半平面问题的基本解。这个推导方法比Gladwell用镜像法和富氏变换要直观。这个基本解对于用边界元法分析半平面域具有任意外形孔洞的应力集中问题将起着十分重要的作用。 相似文献
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In this paper we develop and analyze a bootstrapping algorithm for the extraction of potentials and arbitrary derivatives of the Cauchy data of regular three-dimensional second order elliptic boundary value problems in connection with corresponding boundary integral equations. The method rests on the derivatives of the generalized Green's representation formula, which are expressed in terms of singular boundary integrals as Hadamard's finite parts. Their regularization, together with asymptotic pseudohomogeneous kernel expansions, yields a constructive method for obtaining generalized jump relations. These expansions are obtained via composition of Taylor expansions of the local surface representation, the density functions, differential operators and the fundamental solution of the original problem, together with the use of local polar coordinates in the parameter domain. For boundary integral equations obtained by the direct method, this method allows the recursive numerical extraction of potentials and their derivatives near and up to the boundary surface.
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The general formulation of the transient elastodynamic second boundary value problem in an isotropic linear elastic body with a crack of arbitrary shape by combining the boundary integral equation method and the Laplace transform with respect to time is presented in this paper. Both finite and infinite elastic bodies are considered. A numerical solution of the transformed boundary integral equations is proposed. 相似文献
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An antiplane stationary dynamic problem of elasticity theory for a two-component anisotropic (orthotropic) space is considered, where one component of the pair is weakened by tunnel holes of arbitrary cross section. The space is subjected to the action of time-dependent harmonic shear forces concentrated along some line and shear stresses applied to the surfaces of the holes. To solve the problem, the fundamental solution for a composite space without holes is preliminarily constructed. Using integral representations for displacements in the composite space with holes, the boundary problem of elasticity theory is reduced to an integral equation of second kind, which is solved numerically by the method of quadratures. 相似文献
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I. V. Volovich V. Zh. Sakbaev 《Proceedings of the Steklov Institute of Mathematics》2014,285(1):56-80
A new statement of a boundary value problem for partial differential equations is discussed. An arbitrary solution to a linear elliptic, hyperbolic, or parabolic second-order differential equation is considered in a given domain of Euclidean space without any constraints imposed on the boundary values of the solution or its derivatives. The following question is studied: What conditions should hold for the boundary values of a function and its normal derivative if this function is a solution to the linear differential equation under consideration? A linear integral equation is defined for the boundary values of a solution and its normal derivative; this equation is called a universal boundary value equation. A universal boundary value problem is a linear differential equation together with a universal boundary value equation. In this paper, the universal boundary value problem is studied for equations of mathematical physics such as the Laplace equation, wave equation, and heat equation. Applications of the analysis of the universal boundary value problem to problems of cosmology and quantum mechanics are pointed out. 相似文献
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A.T. Peplow S.N. Chandler-Wilde 《Journal of Mathematical Analysis and Applications》2008,345(1):305-321
The paper considers the solution of the boundary value problem (BVP) consisting of the Helmholtz equation in the region D with a rigid boundary condition on ∂D and its reformulation as a boundary integral equation (BIE), over an infinite cylindrical surface of arbitrary smooth cross-section. A boundary integral equation, which models three-dimensional acoustic scattering from an infinite rigid cylinder, illustrates the application of the above results to prove existence of solution of the integral equation and the corresponding boundary value problem. 相似文献
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泊松类型方程边界元解法 总被引:2,自引:0,他引:2
本文采用高阶拉普拉斯算子基本解将泊松类型方程的区域积分全部变换成边界积分,使计算问题的维数减少一维.通过斯托克斯方程的算例,表明本文所用的方法是有效的方法。 相似文献
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该文运用层位势方法研究了二维Lipschitz区域上一类带L^p边值的非齐次多调和Neumann问题.利用多层S位势,给出了该类问题的惟一积分表示解,其中,多层S位势是经典单层位势的高阶类似物,通过多调和基本解加以定义. 相似文献