The Effect of Source Impedance on Damping Measurements Using Resonance Dwell Testing
Report Number: WL-TR-91-3078 Volume III, p. IBA-1 thru IBA-14
Author(s): Tate, Ralph E.
Corporate Author(s): LTV Aircraft Products Group
Date of Publication: 1991-08
Pages: 14
DoD Task:
Identifier: This paper is part of a conference proceedings. See ADA241313
Abstract:
J.C. Heine developed a test methodology for evaluating the damping in various materials, particularly metals. LTV employs a resonance dwell technique adapted from that of J.C. Heine, which facilitates the use of a smaller shaker from that normally required. This test apparatus permits the rapid characterization of viscoelastic laminates not only for damping, but also for vibroacoustical fatigue resistence. During check-out of the modified apparatus, it was found that the behavior of damped specimens differed markedly from prior results. That is, significantly higher values of damping were observed regardless of measurement technique. The author demonstrates, through the use of impedance modeling techniques, that the differences arise from the coupling the specimen to the electrodynamics of the excitation source. A refinement of the test procedure is outlined to remedy the data anomaly and a discussion of the impact on the interpretation of damping data naturally follows.
Author(s): Tate, Ralph E.
Corporate Author(s): LTV Aircraft Products Group
Date of Publication: 1991-08
Pages: 14
DoD Task:
Identifier: This paper is part of a conference proceedings. See ADA241313
Abstract:
J.C. Heine developed a test methodology for evaluating the damping in various materials, particularly metals. LTV employs a resonance dwell technique adapted from that of J.C. Heine, which facilitates the use of a smaller shaker from that normally required. This test apparatus permits the rapid characterization of viscoelastic laminates not only for damping, but also for vibroacoustical fatigue resistence. During check-out of the modified apparatus, it was found that the behavior of damped specimens differed markedly from prior results. That is, significantly higher values of damping were observed regardless of measurement technique. The author demonstrates, through the use of impedance modeling techniques, that the differences arise from the coupling the specimen to the electrodynamics of the excitation source. A refinement of the test procedure is outlined to remedy the data anomaly and a discussion of the impact on the interpretation of damping data naturally follows.
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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 (GCA-1 through JCB-17)
WL-TR-91-3078 Volume III