Transmission Loss and Absorption of Corrugated Core Sandwich Panels With Embedded ResonatorsThe effect of embedded resonators on the diffuse field sound transmission loss and absorption of composite corrugated core sandwich panels has been evaluated experimentally. Two 1.219 m × 2.438 m panels with embedded resonator arrangements targeting frequencies near 100 Hz were evaluated using non-standard processing of ASTM E90-09 acoustic transmission loss and ASTM C423-09a room absorption test measurements. Each panel is comprised of two composite face sheets sandwiching a corrugated core with a trapezoidal cross section. When inlet openings are introduced in one face sheet, the chambers within the core can be used as embedded acoustic resonators. Changes to the inlet and chamber partition locations allow this type of structure to be tuned for targeted spectrum passive noise control. Because the core chambers are aligned with the plane of the panel, the resonators can be tuned for low frequencies without compromising the sandwich panel construction, which is typically sized to meet static load requirements. Absorption and transmission loss performance improvements attributed to opening the inlets were apparent for some configurations and inconclusive for others.
Document ID
20150001227
Acquisition Source
Langley Research Center
Document Type
Conference Paper
Authors
Allen, Albert R. (NASA Langley Research Center Hampton, VA, United States)
Schiller, Noah H. (NASA Langley Research Center Hampton, VA, United States)
Zalewski, Bart F. (ZIN Technologies, Inc. Celveland, OH, United States)
Rosenthal, Bruce N. (NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
February 3, 2015
Publication Date
September 8, 2014
Subject Category
Spacecraft Design, Testing And PerformanceComposite MaterialsAcoustics