THREE-DIMENSIONAL ANALYSIS OF THIN-WALLED BOX GIRDERS BY ANALYTICAL COMBINATION OF BOUNDARY ELEMENT METHOD AND BLOCK ELEMENT METHOD

Three-dimensional, permeable membrane space sound absorbers have been proposed as practical and economical alternatives to three-dimensional, microperforated panel space sound absorbers. Previously, the sound absorption characteristics of a three-dimensional, permeable membrane space sound absorber were predicted using the two-dimensional boundary element method, but the prediction accuracy was impractical. Herein, a more accurate prediction method is proposed using the three-dimensional boundary element method. In the three-dimensional analysis, incident waves from the elevation angle direction and reflected waves from the floor are considered, using the mirror image. In addition, the dissipated energy ratio is calculated based on the sound absorption of a surface with a unit sound absorption power. To validate the three-dimensional numerical method, and to estimate the improvement in prediction accuracy, the results are compared with those of the measurements and two-dimensional analysis. For cylindrical and rectangular space sound absorbers, three-dimensional analysis provides a significantly improved prediction accuracy for any shape and membrane sample that is suitable for practical use.

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Three-dimensional analysis of a noise barrier using a quasi-periodic boundary element method

The Journal of the Acoustical Society of America ◽

10.1121/1.4921266 ◽

2015 ◽

Vol 137 (6) ◽

pp. 3107-3114 ◽

Cited By ~ 9

Author(s):

Samaneh M. B. Fard ◽

Herwig Peters ◽

Nicole Kessissoglou ◽

Steffen Marburg

Keyword(s):

Boundary Element Method ◽

Boundary Element ◽

Dimensional Analysis ◽

Periodic Boundary ◽

Three Dimensional ◽

Noise Barrier ◽

Element Method

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Three-Dimensional Analysis of Magnetostatic Field by the Boundary Element Method Using Edge Elements

IEEJ Transactions on Fundamentals and Materials ◽

10.1541/ieejfms1990.112.1_21 ◽

1992 ◽

Vol 112 (1) ◽

pp. 21-26

Author(s):

Motoo Tanaka ◽

Hajime Tsuboi ◽

Takayoshi Misaki

Keyword(s):

Boundary Element Method ◽

Boundary Element ◽

Dimensional Analysis ◽

Three Dimensional ◽

Magnetostatic Field ◽

Edge Elements ◽

Element Method

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A Symmetric Galerkin Formulation of the Boundary Element Method for Acoustic Radiation and Scattering

Journal of Computational Acoustics ◽

10.1142/s0218396x97000137 ◽

1997 ◽

Vol 05 (02) ◽

pp. 219-241 ◽

Cited By ~ 20

Author(s):

Z. S. Chen ◽

G. Hofstetter ◽

H. A. Mang

Keyword(s):

Boundary Element Method ◽

Numerical Solution ◽

Boundary Element ◽

Integral Equations ◽

Acoustic Radiation ◽

Numerical Study ◽

Three Dimensional ◽

Galerkin Formulation ◽

Thin Walled ◽

Element Method

A symmetric Galerkin formulation of the Boundary Element Method for acoustic radiation and scattering is presented. The basic integral equations for radiation and scattering of sound are derived for structures, which may consist of a combination of a three-dimensional closed part and thin-walled parts. For the numerical solution of these integral equations a Galerkin-type numerical solution scheme is proposed. The evaluation of the weakly-singular and the hypersingular integrals, occurring in this formulation, is addressed briefly. An improved CHIEF-method is employed in order to prevent the singularity of the coefficient matrix of the algebraic system of equations at so-called irregular frequencies. Subsequently, an algorithm for the automatic determination of the number of nodal unknowns at intersections of thin-walled parts of a structure, or of thin-walled parts and the three-dimensional closed part of a structure, is described. The numerical study contains comparisons of analytical solutions for simple academic examples with the numerical results. In addition, a comparison of measured and computed results is presented for a structure, consisting of both a three-dimensional closed part and a thin-walled part.

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