Enhancing the dynamic range of targeted energy transfer in acoustics using several nonlinear membrane absorbers

Abstract

In order to enhance the robustness and the energy range of efficiency of targeted energy transfer (TET) phenomena in acoustics, we discuss in this paper about the use of multiple nonlinear membrane absorbers in parallel. We show this way, mainly thanks to an experimental set-up with two membranes, that the different absorbers have additional effects that extend the efficiency and the possibilities of observation of TET. More precisely, we present the different behavior of the system under sinusoidal forcing and free oscillations, characterizing the phenomena for all input energies. The frequency responses are also presented, showing successive clipping of the original resonance peak of the system. A model is finally used to generalize these results to more than two NES and to simulate the case of several very similar membranes in parallel which shows how to extend the existence zone of TET.

Nonlinear targeted energy transfer of two coupled cantilever beams coupled to a bistable light attachment

“…To date a wide variety of NESs have been proposed and tested: pure cubic spring in mechanical systems [5], membrane acting as cubic or quintic spring in acoustical systems [6], loudspeaker used as a suspended piston acting as an essentially nonlinear oscillator [7]. A numerical work by Gourdon and Lamarque [8] suggests that a NES described by a nonlinear Duffing equation with negative stiffness, acting as a chaotic system, is able to achieve energy pumping for low energy level.…”

Responses of a two degree-of-freedom system coupled to a nonlinear damper under multi-forcing frequencies

“…A series of papers [1,2,3,4] demonstrated that a passive control of sound at low frequencies can be achieved using a vibroacoustic coupling between the acoustic field (the primary system) and a geometrically nonlinear thin baffled structure (the nonlinear absorber). In [1,2], the thin baffled structure consists of a simple thin circular visco-elastic membrane whereas in [3,4] a loudspeaker used as a suspended piston is considered.…”

“…In [1,2], the thin baffled structure consists of a simple thin circular visco-elastic membrane whereas in [3,4] a loudspeaker used as a suspended piston is considered. In the four papers, theoretical and experimental results are reported considering transient and periodic external excitation.…”

“…In this study, an acoustic medium (as in [1,2,3,4]) is considered as a primary system coupled to a simple thin circular visco-elastic membrane (as in [1,2]). However, two significant differences can be highlighted from these past studies: firstly, the acoustic medium is modeled using two modes and secondly the coupling effect between the primary system and the NES is analyzed under two different harmonic excitations.…”

Acoustic characterization of a nonlinear vibroacoustic absorber at low frequencies and high sound levels

“…Nonlinear vibroacoustic absorbers have shown their ability to reduce sound especially at low frequencies range and high enough sound field levels. They may thus overcome some limitations of classical devices such as porous materials, Helmholtz resonators, perforated plates [1,2,4,5,6].…”