Characterization of Viscoelastic Damping in an Antenna Structure
Report Number: WL-TR-91-3078 Volume II, pages EDF-1 to EDF-14
Author(s): Argento, James, Carlin, Robert, Garcia, Ephrahim
Corporate Author(s): State University of New York at Buffalo
Laboratory: Wright Laboratory
Date of Publication: 1991-08
Pages: 14
DoD Project: 2401
DoD Task: 240104
Identifier: This paper is part of a conference proceedings. See ADA241312
Abstract:
The dynamics of a ribbed antenna structure are examined. The symmetry of the structure generates repeated natural frequencies and hence a "beating" phenomena in the dynamic response of the structure. Two of the antenna's ribs are replaced with passively damped ribs which are treated with a constrained viscoelastic material. Since these repeated natural frequencies cannot be identified using standard frequency domain techniques, a time domain method, the Eigensystem Realization Algorithm (ERA), is employed to measure damping in the repeated and closely spaced natural frequencies. A comparison is made between ERA and the Polyreference identified modal parameters. Consideration is given to a slight structural modification to increase the interaction between the damped and undamped antenna ribs, thereby increasing the overall performance of the viscoelastic damping in each mode.
Provenance: University of Colorado Colorado Springs, Kraemer Family Library
Author(s): Argento, James, Carlin, Robert, Garcia, Ephrahim
Corporate Author(s): State University of New York at Buffalo
Laboratory: Wright Laboratory
Date of Publication: 1991-08
Pages: 14
DoD Project: 2401
DoD Task: 240104
Identifier: This paper is part of a conference proceedings. See ADA241312
Abstract:
The dynamics of a ribbed antenna structure are examined. The symmetry of the structure generates repeated natural frequencies and hence a "beating" phenomena in the dynamic response of the structure. Two of the antenna's ribs are replaced with passively damped ribs which are treated with a constrained viscoelastic material. Since these repeated natural frequencies cannot be identified using standard frequency domain techniques, a time domain method, the Eigensystem Realization Algorithm (ERA), is employed to measure damping in the repeated and closely spaced natural frequencies. A comparison is made between ERA and the Polyreference identified modal parameters. Consideration is given to a slight structural modification to increase the interaction between the damped and undamped antenna ribs, thereby increasing the overall performance of the viscoelastic damping in each mode.
Provenance: University of Colorado Colorado Springs, Kraemer Family Library
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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