Transmission loss of viscoelastic materials containing oriented ellipsoidal coated microinclusions

Abstract

The three-phase self-consistent (SC) micromechanical model of Cherkaoui et al. [J. Eng. Mater. Technol. 116, 274–278 (1994)] is employed to model the anisotropic effects induced by identically oriented, coated, and 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 for the case of spherical inclusions. The use of the SC model for the special case of a biphase effective material is also considered and compared with the complex bounds available in the literature. Parametric studies are presented for the transmission loss in the 0–100kHz frequency range of a 1cm 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 an isotropic composite material having identical constituent material properties and volume fractions.