Evaluation of Acoustic Propagation Paths into the Human Head
Abstract
The overall goal of this research was to develop an acoustic wave propagation model using well-understood and documented computational techniques that track and quantify an air-borne incident acoustic wave propagated around, into and in the human head. The model purpose served two purposes: (1) determine alternate acoustic propagation paths to the cochlear shell that exist besides the normal air-borne acoustic propagation path (eardrum-ossical path) through the auditory canal and (2) quantify sound pressure amplitudes in the cochlear shell (relative to the air-borne sound pressure amplitude) via the alternate propagation paths. A 3D finite-element solid mesh was constructed using a digital image database of an adult male head. Finite-element analysis was used to model the wave propagation through the fluid-solid-fluid media. Instantaneous acoustic pressure waveforms were recorded at various positions inside and outside of the head model, and propagation trajectories (ray paths) were constructed and evaluated from wavefront normals as a function of frequency and incidence angle. The acoustic loss across the skull was estimated to be 33 dB, consistent with theoretical estimates. The computational ray-path results and the theoretical solutions calculated using Snell's law gave a 0.7 difference for low-angle incidence.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 25, 2005
- Accession Number
- ADA437351
Entities
People
- William D. O'brien Jr.
- Yuhui Liu
Organizations
- University of Illinois Urbana–Champaign