Micromechanical modeling of viscoelastic voided composites in the low-frequency approximation.

The self-consistent model of Cherkaoui et al. [J. Eng. Mater. Technol. 116, 274-278 (1994)] is used to compute the effective material moduli of a viscoelastic material containing coated spherical inclusions. Losses are taken into account by introducing the frequency-dependent, complex shear modulus of the viscoelastic matrix. Mode conversion appears through the localization tensors that govern the micromechanical behavior near the inclusions. The results are compared with the scattering model and the data of Baird et al. [J. Acoust. Soc. Am. 105, 1527-1538 (1999)]. The two models are in good agreement. The advantage of the self-consistent model is that it is applicable to the case of nonspherical inclusions embedded in anisotropic materials.