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Proceedings Paper

Vibroacoustics and damping analysis of negative Poisson's ratio honeycombs
Author(s): Fabrizio L. Scarpa; Geoffrey R. Tomlinson
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Paper Abstract

In this paper a novel class of core material for sandwich structures is analyzed from an analytical and numerical point of view. Honeycombs with re-entrant cell geometry present negative in-plane Poisson's ratio coefficients, with an increase of bending stiffness compared to the one of hexagonal honeycomb cores. Due to the orthotropic mechanical properties of this kind of core material it is possible to employ the formulations of laminated orthotropic plates in order to describe the vibroacoustic behavior of simply supported sandwich plates. The natural frequencies of these laminates are sensitive to the geometrical parameters of the core cells. As an example application, an infinite cylindrical sandwich shell in contact with exterior and interior fluid flow is examined. An improvement of transmission loss factors is observed, suggesting a possible use of these cores in acoustic insulation. Damping properties are modeled taking into account the complex modulus of the core material. Two models are examined, one with full viscoelastic core and the other with a free-layer symmetrical beam geometry in order to describe the walls of the core cells. Both cases show a significant increase of the storage moduli of the cores compared to the ones of a regular honeycomb.

Paper Details

Date Published: 16 June 1998
PDF: 10 pages
Proc. SPIE 3327, Smart Structures and Materials 1998: Passive Damping and Isolation, (16 June 1998); doi: 10.1117/12.310695
Show Author Affiliations
Fabrizio L. Scarpa, Univ. of Sheffield (United Kingdom)
Geoffrey R. Tomlinson, Univ. of Sheffield (United Kingdom)

Published in SPIE Proceedings Vol. 3327:
Smart Structures and Materials 1998: Passive Damping and Isolation
L. Porter Davis, Editor(s)

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