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examination of the measurement of absorption using the reverberant room method for highly absorptive acoustic foamThe absorption coefficient for material specimens are needed to quantify the expected acoustic performance of that material in its actual usage and environment. The ASTM C423-09a standard, "Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberant Room Method" is often used to measure the absorption coefficient of material test specimens. This method has its basics in the Sabine formula. Although widely used, the interpretation of these measurements are a topic of interest. For example, in certain cases the measured Sabine absorption coefficients are greater than 1.0 for highly absorptive materials. This is often attributed to the diffraction edge effect phenomenon. An investigative test program to measure the absorption properties of highly absorbent melamine foam has been performed at the Riverbank Acoustical Laboratories. This paper will present and discuss the test results relating to the effect of the test materials' surface area, thickness and edge sealing conditions. A follow-on paper is envisioned that will present and discuss the results relating to the spacing between multiple piece specimens, and the mounting condition of the test specimen.
Document ID
20150023091
Document Type
Conference Paper
Authors
Hughes, William O.
(NASA Glenn Research Center Cleveland, OH United States)
McNelis, Anne M.
(NASA Glenn Research Center Cleveland, OH, United States)
Chris Nottoli
(Alion Science and Technology Chicago, IL, United States)
Eric Wolfram
(Alion Science and Technology Chicago, IL, United States)
Date Acquired
December 15, 2015
Publication Date
October 27, 2015
Subject Category
Acoustics
Report/Patent Number
GRC-E-DAA-TN26791
Meeting Information
Aerospace Testing Seminar(Los Angeles, CA)
Funding Number(s)
WBS: WBS 585777.08.50.66.22.10
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
Absorption
Payload Fairing
Acoustic Foam
Acoustics

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