Experimental study of a hybrid electro-acoustic nonlinear membrane absorber

P. Y. Bryk (1) , S Bellizzi (1) , Renaud Côte (1)

1 LMA - Laboratoire de Mécanique et d'Acoustique [Marseille]

A hybrid electro-acoustic nonlinear membrane absorber working as a nonlin-ear energy sink (here after named EA-NES) is described. The device is composed of a thin circular visco-elastic membrane working as an essentially cubic oscilla-tor. One face of the membrane is coupled to the acoustic field to be reduced and the other face is enclosed. The enclosure includes a loudspeaker for the control of the acoustic pressure felt by the rear face of the membrane through proportional feedback control. An experimental setup has been developed where the EA-NES is weakly coupled to a linear acoustic system. The linear acoustic system is an open-ended tube, coupled on one side to the EA-NES by a box, and on the other side to a source loudspeaker by another box. Only sinusoidal forcing is considered. It is shown that the EA-NES is able to perform resonance capture with the acoustic field, resulting in noise reduction by targeted energy transfer, and to operate in a large frequency band, tuning itself passively to any linear system. We demonstrate the ability of the feedback gain defining the active loop to modify the resonance frequency of the EA-NES, which is a key factor to tune the triggering threshold of energy pumping. The novelty of this work is to use active control combined to passive nonlinear transfer energy to improve it. In this paper, only experimental results are analyzed.

Mots clés: Noise Reduction; Hybrid Absorber; Nonlinear Energy Sink; Electroacoustic Absorber; High Sound Level; Low Frequency

Domaines: Acoustique [physics.class-ph]; Vibrations [physics.class-ph]

P. Y. Bryk, S Bellizzi, Renaud Côte. Experimental study of a hybrid electro-acoustic nonlinear membrane absorber. Journal of Sound and Vibration, 2018, 424, pp.224-237. ⟨10.1016/j.jsv.2018.03.014⟩. ⟨hal-01754878⟩