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Title
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Integrally Damped Honeycomb Structural Concepts to Increase Noise Transmission Loss
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Description
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This paper describes the design, analysis, fabrication, and testing of design concepts to add passive damping to honeycomb panels to enhance the noise transmission loss in honeycomb structures. The loss factors for several damping material and panel configurations were analyzed. Statistical Energy Analyses (SEA) were then performed to predict the expected benefits of the calculated panel loss factors in terms of increased acoustic transmission loss through the panels. Based on the analyses, a honeycomb panel structural design concept was developed and three 6-ft by 6-ft panels were fabricated for acoustic testing. The first was a baseline bare honeycomb panel with no passive damping treatment, the second incorporated a NITRILE rubber material, and the third incorporated a 3M ISD 113 viscoelastic material. Acoustic testing was performed in a split reverberant/anechoic chamber at the Boeing Noise Engineering Laboratory. The results of the acoustic testing verified the predicted acoustic transmission loss and performance of the damped panels. The acoustic test results for the NITRILE damped panel showed less transmission loss than predicted indicating an apparent problem with the honeycomb core cutting into the NITRILE rubber during the fabrication of the panel. This was verified by radiographic inspection and subsequent sectioning and visual inspection of the panel.
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Creator
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Newton, Jefferson F.
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Ikegami, Roy
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Carbery, David J.
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Publisher
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Wright-Patterson Air Force Base, OH : Wright Laboratory, Flight Dynamics Directorate, Air Force Systems Command
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Date
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1991
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Format
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1 online resource (7 pages) : ill.
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Type
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article
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Abstract
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This paper describes the design, analysis, fabrication, and testing of design concepts to add passive damping to honeycomb panels to enhance the noise transmission loss in honeycomb structures. The loss factors for several damping material and panel configurations were analyzed. Statistical Energy Analyses (SEA) were then performed to predict the expected benefits of the calculated panel loss factors in terms of increased acoustic transmission loss through the panels. Based on the analyses, a honeycomb panel structural design concept was developed and three 6-ft by 6-ft panels were fabricated for acoustic testing. The first was a baseline bare honeycomb panel with no passive damping treatment, the second incorporated a NITRILE rubber material, and the third incorporated a 3M ISD 113 viscoelastic material. Acoustic testing was performed in a split reverberant/anechoic chamber at the Boeing Noise Engineering Laboratory. The results of the acoustic testing verified the predicted acoustic transmission loss and performance of the damped panels. The acoustic test results for the NITRILE damped panel showed less transmission loss than predicted indicating an apparent problem with the honeycomb core cutting into the NITRILE rubber during the fabrication of the panel. This was verified by radiographic inspection and subsequent sectioning and visual inspection of the panel.
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Date Issued
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1991-08
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Extent
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7
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Corporate Author
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Boeing Aerospace & Electronics
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Laboratory
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Wright Laboratory
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Report Number
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WL-TR-91-3078 Volume II, pages FBA-1 to FBA-7
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DoD Project
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2401
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DoD Task
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240104
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Distribution Conflict
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No
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Index Abstract
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Contrails only
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Photo Quality
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Complete
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Distribution Classification
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1
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Report Availability
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Full text available
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Provenance
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University of Colorado Colorado Springs, Kraemer Family Library
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Identifier
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ADA241312
