Numerical and experimental investigations on the acoustic performances of membraned Helmholtz resonators embedded in a porous matrix

Abstract

Acoustic performances of two concepts based on the integration of an elastic membrane in the front wall of a cavity and Helmholtz resonator embedded in a melamine matrix are studied. Membranes are made of acrylic material, this latter is first characterized with a uniaxial test in order to extract the mechanical properties needed to model the membrane. Analytical, numerical and experimental investigations are performed so as to determine the acoustical potential of the proposed systems in terms of absorption and transmission loss. The contribution to the sound absorption can be positive or negative at the resonator resonances, an analytical model is proposed to highlight the physical phenomena related to these effects. In addition, a multiphysics numerical model combining the acoustic-mechanical interaction has been developed and validated by comparison with the experimental data measured using an impedance tube. The studied concepts could offer significant enhancements of sound transmission loss properties in the low frequencies but also on acoustic absorption in specific frequency bands.

Origami-based auxetic tunable Helmholtz resonator for noise control

“…These actuation systems will probably be made from smart materials such as shape memory alloys [50] or polymers [51]. Finally, investigations on the materials to be used for the manufacturing of the origami are required, as the structural behavior is expected to play an important role in the dynamics of the system, and combining Helmholtz resonances with structural resonances could be a promising way to enhance the performances of the acoustic device [13].…”

“…The array provides a relatively wide attenuation bandwidth (compared to the use of a single DE resonator), which can be shifted using an applied voltage. Lastly, Abbad et al [18,13] presented an adaptive Helmholtz resonator based on DE, embedded in a melamine foam. The proposed concept consists in replacing the top wall of a conventional cylindrical Helmholtz resonator with a dielectric membrane.…”

Sound transmission loss of porous materials in ducts with embedded periodic scatterers

“…The Delany-Bazley model, instead of more complete and precise models such as the Johnson-Champoux-Allard model (Abbad et al, 2019), is chosen to model the porous material due to the comparative simplicity of the former model over the latter. With the Delany-Bazley model (Allard and Atalla, 2009;Gulia and Gupta, 2018), the complex wave number (k c ) and complex acoustic impedance (Z c ) for the porous material can be estimated by…”

Research of the Resonance Properties of Helmholtz Resonators

“…As a result of the experiment, it was found that the resonant frequencies of the resonator in the plates will be lower than the frequency of resonator natural vibrations. In work [9], researches of resonators enclosed in a melamine casing were carried out. The resonant frequency of the construction, which was matched to the Helmholtz resonator natural frequency (in this article), was obtained.…”