Elastic Wave Propagation in Inhomogeneous Lossy Media with Special Reference to Powders.
Abstract
Elastic wave propagation in actual fact is the transport of energy in a medium that acts as a sink for this energy. Engineering and physical applications rely upon an understanding of the wave propagation process to model systems and describe the physical world, and, as such one desires to broaden his knowledge of the actual propagation process in real inhomogeneous media. In this work, on examines the vector wave equation developed for an anisotropic, inhomogeneous lossy medium with a set of 'effective' Lame' constants derived from microscopic considerations of the medium and develops a composite loss function, L, to account for the energy loss mechanisms that occur as the wave propagates. This loss function is incorporated into the general equations of motion and series solutions for bulk, and surface waves in the inhomogenous lossy medium are derived. The displacement fields are examined over the frequency regime in the near and far field for the waves. The effective Lame' parameters are included in the solution, and their contribution, as well as the frequency contribution to the wave field is seen. Higher orders of scattering and diffraction are seen as well as the an harmonicites and nonlinear effects of losses. These effects may be observed in the general wavefield description. Also the effect of losses on the dispersion behavior is observed as a frequency shift of the wave.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 28, 1980
- Accession Number
- ADA085262
Entities
People
- Geoffrey Roy Akers
Organizations
- Naval Underwater Systems Center