Integrally Damped Honeycomb Structural Concepts to Increase Noise Transmission Loss
Report Number: WL-TR-91-3078 Volume II, pages FBA-1 to FBA-7
Author(s): Newton, Jefferson F., Ikegami, Roy, Carbery, David J.
Corporate Author(s): Boeing Aerospace & Electronics
Laboratory: Wright Laboratory
Date of Publication: 1991-08
Pages: 7
DoD Project: 2401
DoD Task: 240104
Identifier: This paper is part of a conference proceedings. See ADA241312
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.
Provenance: University of Colorado Colorado Springs, Kraemer Family Library
Author(s): Newton, Jefferson F., Ikegami, Roy, Carbery, David J.
Corporate Author(s): Boeing Aerospace & Electronics
Laboratory: Wright Laboratory
Date of Publication: 1991-08
Pages: 7
DoD Project: 2401
DoD Task: 240104
Identifier: This paper is part of a conference proceedings. See ADA241312
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.
Provenance: University of Colorado Colorado Springs, Kraemer Family Library
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Via the Defense Technical Information Center (DTIC): Identifier: This paper is part of a conference proceedings. Access a record for the conference proceedings, and possibly a pdf download of the report, at DTIC Via National Technical Report Library: This report may be available for download from NTRL. Use the Title from this record to locate the item in DTIC Online Indications of Public Availability No digital image of an index entry indicating public availability is currently available There has been no verification of an indication of public availability from an inside cover statementRelated report(s)
This report is part of the following conference:
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Proceedings of Damping '91: 13-15 February 1991 San Diego, California (EAA-1 through GBC-16)
WL-TR-91-3078 Volume II