In this paper, shielding effectiveness (SE) of a perforated enclosure with imperfectly conducting walls is evaluated. To this end, first, an accurate numerical technique based on method of Moments (MoM) ispresented. In this method, lossy metallic walls of the enclosure are replaced by equivalent electric surfacecurrent sources. Then, the impedance boundary condition on the imperfectly conductin...

This paper describes the Fortran subroutine BERIM3 that delivers a computational solution to the acoustic field both within and outside of a cavity with one opening into the exterior domain. The mathematical model is based on coupling the usual direct boundary integral equation for the interior region to the Rayleigh integral for the mouth of the domain and the exterior region. The usual bounda...

This paper describes the Fortran subroutine BERIM3 that delivers a computational solution to the acoustic field both within and outside of a cavity with one opening into the exterior domain. The mathematical model is based on coupling the usual direct boundary integral equation for the interior region to the Rayleigh integral for the mouth of the domain and the exterior region. The usual bounda...

In the context of two-dimensional linear elasticity, this paper presents the closed form of the integrals that arise from both the standard (collocation) boundary element method and the symmetric Galerkin boundary element method. Adopting polynomial shape functions of arbitrary degree on straight elements, <nite part of Hadamard, Cauchy principal values and Lebesgue integrals are computed analy...

Boundary element methods are being applied with increasing frequency to time dependent problems, especially to boundary value problems for parabolic differential equations. Here we shall consider the heat equation as the prototype of such equations. Various types of integral equations arise when solving boundary value problems for the heat equation. An important one is the single layer heat pot...

This paper introduces a numerical method to solve anti-periodic boundary value problems. The proposed method converts anti-periodic boundary value problem to a Fredholm integral equation and solves it by Galerkin method. The approximate solution converges to the exact solution and satisfies anti-periodic boundary conditions completely. Also, the convergence rate of the proposed method is given ...

We describe a modified Nyström method for the discretization of the weakly singular boundary integral operators which arise from the formulation of linear elliptic boundary value problems as integral equations. Standard Nyström and collocation schemes proceed by representing functions via their values at a collection of quadrature nodes. Our method uses appropriately scaled function values in l...

1.1 INTRODUCTION This paper gives a survey on additive Schwarz methods applied to the h and p versions of the boundary element method. We consider weakly singular and hypersingular integral equations, namely the single layer potential operator and the normal derivative of the double layer potential operator. That means we have to consider weak formulations of the form

We present a new version of panel clustering for the boundary element method. The intention of this method is to substantially reduce the work for solving boundary integral equations on complicated two-dimensional manifolds in R 3. The method is based upon a hierarchical structuring of the surface and an approximative factorization of the kernel of the associate integral operator in terms of sp...

A hierarchical multilevel preconditioner is constructed for an efficient solution of a first kind boundary integral equation with the single layer potential operator discretized by a boundary element method. This technique is based on a hierarchical clustering of all boundary elements as used in fast boundary element methods. This hierarchy is applied to define a sequence of nested boundary ele...