@article {Svetgoff:2018:0736-2935:4810,
title = "Absorption Characteristics of Membrane-Embedded Acoustic Liners",
journal = "INTER-NOISE and NOISE-CON Congress and Conference Proceedings",
parent_itemid = "infobike://ince/incecp",
publishercode ="ince",
year = "2018",
volume = "258",
number = "3",
publication date ="2018-12-18T00:00:00",
pages = "4810-4821",
itemtype = "ARTICLE",
issn = "0736-2935",
url = "https://ince.publisher.ingentaconnect.com/content/ince/incecp/2018/00000258/00000003/art00013",
author = "Svetgoff, Alexander and Manimala, James",
abstract = "Acoustic liners are used extensively to reduce noise emitted by aircraft engines. However, conventional acoustic liners are largely ineffective for low-frequency noise content (~1000 Hz) due to impractical mass and volume requirements. In this study, membrane-embedded liners are investigated
as a potential solution to attenuate low-frequency noise in aerospace applications. In its basic form, such a liner is akin to a double degree-of-freedom liner implementing a membrane as septum in lieu of a typical wire mesh. Introducing the membrane provides a lightweight, compact structural
element whose resonance can be tuned to interact with acoustic resonances to enhance absorption and bandwidth for low-frequencies. Material, geometry, tension and location of membrane are used as tunable parameters. Tests on several membrane-embedded and baseline double degree-of-freedom liner
configurations were run using the normal incidence tube at NASA Langley Research Center with broadband excitation at sound pressure levels of 120 and 140 dB. Results indicate low-frequency broadband absorption is significantly enhanced for membrane-embedded liners without any appreciable increase
in overall mass or volume vis-{\‘a}-vis the baseline. Correlations with simulations are utilized to understand underlying interactive mechanisms involved. Realizing such liners using aerospace materials is expected to provide an effective means to attenuate low-frequency airborne noise.",
}