Hearing Protection against Low Frequency Weapon Noise.
Abstract
This investigation sought to determine the material properties that are responsible for low frequency (100 Hz) noise attenuation in foam earplugs. An attempt was made to determine the following for each earlplug type investigated: (1) chemical structure; (2) energy absorption at low frequencies; (3) noise attenuation as a function of foam density; and (4) the foam geometry. One experimental foam was found to give good low frequency noise protection but the physical properties responsible are unknown. Earplug materials tested were either polyvinyl chloride or polyurethane. All the commercial plugs contained some extractable plasticizer. Energy absorption was measured on two different dynamic mechanical analysis testers. Density was determined from weight and volume measurements and foam geometry was determined microscopically. Although the properties of foam varied widly, no property was found which gave a reasonable correlation with the foam's ability to attenuate low frequency noise. A suggestion is made for the collection of air permeability data, along with the basis for that suggestion. One additonal foam material was found which gave reasonable low-frequency noise attenuation in tests on the laboratory manekin. Keywords: Acoustic attenuation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 05, 1983
- Accession Number
- ADA164746
Entities
People
- Curtis R. Smith
- Roy M. Broughton Jr.
Organizations
- Auburn University