Transmission loss of a submerged viscoelastic slab containing oblate spheroidal coated microinclusions

Abstract

The three-phase self-consistent (SC) micromechanical model of Cherkaoui et al. [J. Eng. Mater. and Technol. 116, 274–278 (1994)] is employed to model the anisotropic effects induced by identically oriented coated ellipsoidal microinclusions embedded in a viscoelastic matrix. Numerical predictions of the lossy and anisotropic behavior of the viscoelastic composite material are obtained. This study is an extension of a previous paper [J. Acoust. Soc. Am. 112 (5), 1937–1943 (2002)], where the agreement of the micromechanical approach with the long wavelength scattering model of Baird et al. [J. Acoust. Soc. Am. 105 (3), 1527–1538 (1999)] was demonstrated. The use of the SC model for the special case of a biphase effective material is also considered and compared with the complex bounds given by Gibiansky and Lakes [J. Mech. Mater. 16, 317–331 (1993)]. Parametric studies are presented for the transmission loss in the 0–100-kHz frequency range of a 1-cm-thick composite material slab containing oblate spheroidal inclusions of varying aspect ratios when the slab is submerged under water. The results are compared with the case of a composite material having identical constituent material properties and volume fractions as the oblate case but containing spherical inclusions.