Integrally Damped Honeycomb Structural Concepts to Increase Noise Transmission Loss

Item

Title
Integrally Damped Honeycomb Structural Concepts to Increase Noise Transmission Loss
Description
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.
Creator
Newton, Jefferson F.
Ikegami, Roy
Carbery, David J.
Publisher
Wright-Patterson Air Force Base, OH : Wright Laboratory, Flight Dynamics Directorate, Air Force Systems Command
Date
1991
Format
1 online resource (7 pages) : ill.
Type
article
Abstract
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.
Date Issued
1991-08
Extent
7
Corporate Author
Boeing Aerospace & Electronics
Laboratory
Wright Laboratory
Report Number
WL-TR-91-3078 Volume II, pages FBA-1 to FBA-7
DoD Project
2401
DoD Task
240104
Distribution Conflict
No
Index Abstract
Contrails only
Photo Quality
Complete
Distribution Classification
1
Report Availability
Full text available
Provenance
University of Colorado Colorado Springs, Kraemer Family Library
Identifier
ADA241312

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Items with "Has Part: Integrally Damped Honeycomb Structural Concepts to Increase Noise Transmission Loss"
Title Class
Proceedings of Damping '91: 13-15 February 1991 San Diego, California (EAA-1 through GBC-16)