Fast finite-element analysis for damping of automotive structures having elastic bodies, viscoelastic bodies, porous media, and gas

A numerical method is proposed to calculate damping properties for automotive soundproof structures involving solid bodies, porous media, and air in two-dimensional regions. Both effective density and bulk modulus have a complex quantity to represent damped sound fields in the porous media. Particle...

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Bibliographic Details
Published in:The Journal of the Acoustical Society of America 2006-11, Vol.120 (5_Supplement), p.3343-3343
Main Authors: Yamaguchi, Takao, Kurosawa, Yoshio
Format: Article
Language:English
Online Access:Get full text
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Summary:A numerical method is proposed to calculate damping properties for automotive soundproof structures involving solid bodies, porous media, and air in two-dimensional regions. Both effective density and bulk modulus have a complex quantity to represent damped sound fields in the porous media. Particle displacements in the media are discretized using a finite-element method. For damped solid bodies, displacements are formulated using conventional finite elements including complex modulus of elasticity. Displacement vectors as common unknown variables are solved under coupled condition between solid bodies, porous media, and gas. Further, by applying an asymptotic method to a complex eigenvalue problem, explicit expressions of modal loss factor for the mixed structures are derived. The proposed methods yield appropriate results for some typical problems and this method diminishes computational time for large-scaled finite-element models. Moreover, it is found that damping can be coupled in the mixed structures. An expression to calculate a share of dissipated energy for each element in mixed structures is also derived. Damping behaviors in sound bridge phenomena are analyzed using the proposed method.
ISSN:0001-4966
1520-8524
DOI:10.1121/1.4781360