31 July 2003 Vibration damping by coupling to lossy low-wave-speed media
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In this paper, we study vibration damping in structures coupled to low-density media (such as powder or foam) in which the speed of sound propagation is relatively low. The results of several experiments in which flexural vibration of aluminum beams over a broad frequency range is damped by the introduction of a layer of lossy low-wave-speed foam are presented. We find that at frequencies high enough to set up standing waves through the thickness of the foam, damping coefficients as high as 0.07 can be obtained with a foam layer whose mass is 3.9% of that of the beam. Next, a model is presented for the flexural dynamics of coupled beam-foam systems in which we treat the foam material as a continuum in which waves of dilatation and distortion can propagate. Approximate solutions for the frequency response of the primary beam are obtained by means of a modal expansion, and the results are in close agreement with the measured responses.
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Kripa K. Varanasi, Kripa K. Varanasi, Samir A. Nayfeh, Samir A. Nayfeh, "Vibration damping by coupling to lossy low-wave-speed media", Proc. SPIE 5052, Smart Structures and Materials 2003: Damping and Isolation, (31 July 2003); doi: 10.1117/12.483799; https://doi.org/10.1117/12.483799

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