Session: SYMP 3-4: Programming and Modeling

Paper Number: 140546

140546 - Towards the Programming of Nonlinear Actuators: The Example of the Nonlinear Electroacoustic Resonator 

Acoustic devices of multiple natures have been studied for years [1]. Passive devices such as acoustic foams or Helmholtz resonators present benefits and downsides. The main disadvantages of the passive devices are their inability to adjust their properties to absorb on a wide range of frequencies, and the high space volume that they occupy to be efficient at low frequencies (under 1 kHz) [2]. Active devices are very efficient in spatially limited areas but require large amounts of energy [3]. The idea of Olson and May to modify the impedance of a surface using electrical current while keeping the surface acoustically passive is called Impedance Control [4]. This method allows the creation of resonators that can be tuned using electrical current. In this study, a loudspeaker is collocated to microphones, and equipped with a processor that estimates at each time step the electrical current to send into the loudspeaker coil. It creates an Electroacoustic Resonator (ER) which is acoustically passive but can be digitally tuned. However, linear resonators are limited in their frequency bandwidth of efficiency. While nonlinear vibration absorbers have been studied for years in many fields such as mechanics and aeronautics, acoustic nonlinear resonators have been left aside until recently due to the high activation threshold of nonlinear regimes [5,6]. As a result, this research uses a method that allows to digitally program and activate nonlinear behaviors for all excitation amplitudes [7]. While the ER loudspeaker stays in its linear regime, the behavior can present polynomial or non-polynomial nonlinearities that can be activated at all excitation amplitudes in the limits of the loudspeaker and microphone capabilities. This research proposes the introduction of a discontinuous piecewise linear restoring force, which features multiple nonlinear phenomena such as a quasi-periodic regime.

The discontinuous piecewise linear behavior is digitally programmed in the ER processor. The ER is coupled to a tube acoustic mode to control through a coupling box. Experimental results are presented against numerical predictions of an analytical model.

 

[1] Bruneau, M. (2010). Fundamentals of Acoustics. ISTE, London, UK.

[2] Delany M., Bazley E. (1970). Acoustical properties of fibrous absorbent materials. Applied Acoustics. 3(2):105-116.

[3] Miljkovic D. (2016). Active Noise Control: From Analog to Digital – Last 80 Years. 39th International Convention on Information and Communication Technology, Electronics and Microelectronics, MIPRO 2016 – Proceedings. 1151-1156.

[4] Olson H., May E. (1953). Electronic Sound Absorber. Journal of the Acoustical Society of America. 25(6):1130-1136.

[5] Gourdon E., Ture Savadkoohi A., Alamo Vargas V. (2018) Targeted Energy Transfer From One Acoustical Mode to a Helmholtz Resonator With Nonlinear Behavior. Journal of Sound and Vibration. 140(6):061005.

[6] Guo X., Lissek H., Fleury R. (2020) Improving Sound Absorption Through Nonlinear Active Electroacoustic Resonators. Physical Review Applied. 13(1):014018.

[7] De Bono E., Morell M., Collet M., Gourdon E., Ture Savadkoohi A., Ouisse M., Lamarque C.H. (2024). Model-inversion control to enforce tunable Duffing-like acoustical response on an Electroacoustic resonator at low excitation levels. Journal of Sound and Vibration. 570:118070.

Presenting Author: Manuel Collet CNRS, Ecole Centrale de Lyon, ENTPE, LTDS, UMR5513, 69130 Ecully, France

Presenting Author Biography: Manuel COLLET graduated his PhD from the French Engineering School Centrale Lyon in 1996, and is now a Researcher at the LTDS laboratory.

Authors:

Maxime Morell
Manuel Collet
Emmanuel Gourdon
Emanuele De Bono
Alireza Ture Savadkoohi