S.Aoki¹, K.Amaya², M.Urago³, A.Nakayama⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.2, pp. 123-132, 2004, DOI:10.3970/cmes.2004.006.123

Abstract The Fast Multipole Boundary Element Method(FMBEM) which is suitable for a large scale computation is applied to corrosion analysis. Many techniques of the FMBEM on the potential problems can be usefully employed. Additionally, some procedures are developed for corrosion analysis. To cope with the non-linearity due to the polarization curve, the Bi-CGSTAB iterative method which is commonly used in the FMBEM is modified. To solve infinite domain problems, the M₀⁰ which is obtained naturally in the multipole expansion is conveniently used. A pipe element for the FMBEM is developed. A couple of example problems are More >

Hiroshi Okada¹, Yasuyoshi Fukui¹, Noriyoshi Kumazawa¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.2, pp. 135-150, 2004, DOI:10.3970/cmes.2004.005.135

Abstract A method to obtain the effective mechanical properties of particulate composite materials is presented in this paper. The methodology is based on the boundary element method (BEM) coupled with analytical solutions for ellipsoidal inclusions such as Eshelby's tensor. There is no numerical integration for the surfaces or the domains of distributed particles, and, therefore, proposed technique is very efficient. Homogenization analysis based on representative volume element (RVE) is carried out considering a unit cell containing many particles (up to 1000). By using a conventional BEM approach (i.e., multi-region BEM), it would be extremely difficult to More >

Youssef F. Rashed¹

CMC-Computers, Materials & Continua, Vol.1, No.4, pp. 319-326, 2004, DOI:10.3970/cmc.2004.001.319

Abstract The present paper develops a new technique for treatment of self-weight for building slabs in the boundary element method (BEM). Due to the use of BEM in the analysis, all defined variables are presented on the slab boundary (mesh is defined only along the slab boundary). Self-weight, however, is usually defined over slab domain, hence domain discretisation is required, which spoils the main advantage of the BEM. In this paper a new method is presented to transform self-weight domain integrals to the boundary for such slabs. The proposed method is based on using the so-called More >

X.S. Sun¹, L.X. Huang¹, Y.H. Liu¹, Z.Z. Cen^1,2

CMC-Computers, Materials & Continua, Vol.1, No.1, pp. 91-106, 2004, DOI:10.3970/cmc.2004.001.091

Abstract The Boundary Element Method (BEM) is introduced to analyze the elasto-plastic problems of 2-D orthotropic bodies. With the help of known boundary integral equations and fundamental solutions, a numerical scheme for elasto-plastic analysis of 2-D orthotropic problems with the BEM is developed. The Hill orthotropic yield criterion is adopted in the plastic analysis. The initial stress method and tangent predictor-radial return algorithm are used to determine the stress state in solving the nonlinear equation with the incremental iteration method. Finally, numerical examples show that the BEM is effective and reliable in analyzing elasto-plastic problems of More >

S.-C. Hsiao¹, M.S. Ingber²

CMC-Computers, Materials & Continua, Vol.1, No.1, pp. 51-58, 2004, DOI:10.3970/cmc.2004.001.051

Abstract The lateral migration of nonneutrally-buoyant spherical particles in Poiseuille flow is investigated numerically using the boundary element method. In particular, the steady, Navier-Stokes equations are solved using a classical domain integration method treating the nonlinear terms as pseudo-body forces. The numerical results for the lateral migration velocity are compared with experimental data. The numerical results indicate that the lateral migration velocity does not scale linearly with the Reynolds number. The methodology is extended to include non-Newtonian power-law fluids. The migration velocity is significantly affected for particles suspended in this class of fluids and can actually More >

B. Mochnacki¹, E. Majchrzak²

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 431-438, 2003, DOI:10.3970/cmes.2003.004.431

Abstract In the paper the analysis of transient temperature field in the domain of biological tissue subjected to an external heat source is presented. Because of the geometrical features of the skin the heat exchange in domain considered is assumed to be one-dimensional. The thermophysical parameters of successive skin layers (dermis, epidermis and sub-cutaneous region) are different, at the same time in sub-domains of dermis and sub-cutaneous region the internal heat sources resulting from blood perfusion are taken into account. The degree of the skin burn results from the value of the so-called Henriques integrals. The More >

Ch. Zhang², A. Savaidis³

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.5, pp. 603-618, 2003, DOI:10.3970/cmes.2003.004.603

Abstract A novel non-hypersingular time-domain traction BEM is presented for three-dimensional (3-D) transient elastodynamic crack analysis. The initial-boundary value problem is formulated as a set of non-hypersingular time-domain traction boundary integral equations (BIEs). To solve the time-domain traction BIEs, a time-stepping scheme based on the convolution quadrature formula of Lubich (1988a,b; 1994) for temporal discretization and a collocation method for spatial discretization is adopted. Numerical examples are given for an unbounded solid with a penny-shaped crack under a tensile and shear impact loading. A comparison of the present time-domain BEM with the conventional one shows that More >

J. P. Agnantiaris¹, D. Polyzos^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.1, pp. 197-212, 2003, DOI:10.3970/cmes.2003.004.197

Abstract A Boundary Element Method (BEM), for the three-dimensional solution of both non-axisymmetric and axisymmetric coupled acoustic-elastic problems in the frequency domain, is presented. The present BEM makes use of the Burton and Miller integral equation for infinite acoustic spaces, while elastic structures are dealt with the standard boundary integral equation of elastodynamics. The axisymmetric formulation involves the use of the fast Fourier transform algorithm. Highly accurate numerical algorithms are used for the evaluation of singular integrals, while nearly singular integrals are treated, also with high accuracy, through the use of practical numerical techniques, for both More >

A. Aimi¹, M. Diligenti¹, F. Lunardini¹, A. Salvadori²

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.1, pp. 31-50, 2003, DOI:10.3970/cmes.2003.004.031

Abstract This paper is devoted to the study of a new application of the Panel Clustering Method [Hackbusch and Sauter (1993); Hackbusch and Nowak (1989)]. By considering a classical 3D Neumann screen problem in its boundary integral formulation discretized with the Galerkin BEM, which requires the evaluation of double integrals with hypersingular kernel, we recall and use some recent results of analytical evaluation of the inner hypersingular integrals. Then we apply the Panel Clustering Method (PCM) for the evaluation of the outer integral. For this approach error estimate is shown. Numerical examples and comparisons with classical More >

G.D. Hatzigeorgiou¹, D.E. Beskos¹

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 791-802, 2002, DOI:10.3970/cmes.2002.003.791

Abstract This paper presents a general boundary element methodology for the dynamic analysis of three-dimensional inelastic solids and structures. Inelasticity is simulated with the aid of the continuum damage theory. The elastostatic fundamental solution is employed in the integral formulation of the problem and this creates in addition to the surface integrals, volume integrals due to inertia and inelasticity. Thus an interior discretization in addition to the usual surface discretization is necessary. Isoparametric linear quadrilateral elements are used for the surface discretization and isoparametric linear hexahedra for the interior discretization. Advanced numerical integration techniques for singular More >