Diffuse wave density and directionality in anisotropic solids

TL;DR

This paper derives general results for diffuse waves in anisotropic solids, providing formulas for modal density and energy distribution, with calculations showing notable deviations from isotropic cases even with moderate anisotropy.

Contribution

It introduces concise expressions for modal density and the participation factor matrix in anisotropic solids, advancing understanding of diffuse wave behavior in such materials.

Findings

Participation factor matrix deviates from identity in anisotropic materials

Significant anisotropy effects observed at moderate levels

Provides formulas applicable to various materials

Abstract

Several general results are derived for diffuse waves in anisotropic solids, including concise expressions for the modal density per unit volume and for the participation factor matrix G. The latter is a second order tensor which describes the orientational distribution of diffuse wave or reverberant energy, and reduces to the identity I under isotropy. Calculations of G for a variety of example materials show significant deviation from I even under moderate levels of anisotropy.