Broadening sound absorption coefficient with hybrid resonances

Bucciarelli, Fabrizio; Meo, Michele

doi:10.1016/j.apacoust.2019.107136

Cited by 18 publications

(7 citation statements)

References 22 publications

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“…Figure 5 represents the absorption coefficients for the different excitation signals from the primary sound source, displaying absorption peaks that occur at a low-frequency range, between 300 and 650 Hz. The occurrence of multiple peaks in this low frequency range has been previously investigated in membrane-type samples synthesised with silicon [29,30]. In addition to this, a clear shift in the frequency peaks as the voltage level is increased can also be appreciated, with this shift being more evident towards the higher end of the spectrum.…”

Section: Passive Systemmentioning

confidence: 81%

Investigation of a dynamic active/passive noise cancellation of polyborosiloxane thin membrane gel

Myronidis

Malfense-Fierro

Meo

et al. 2023

Active and Passive Smart Structures and Integrated Systems XVII

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This study proposes a multifunctional, thin membrane gel based on a formulation of PDMS and boron. The proposed gel offers a dynamic passive stimuli-responsive sound absorption at low frequencies, which can be transformed to active noise cancellation with the use of a secondary sound source. The passive behaviour of the proposed material is the result of a dynamic phase transition in the material’s polymeric network, activated by the interaction with the travelling sound pressure wave. The presence and extent of the phase transition in the material was investigated via Fourier transform infrared spectroscopy and oscillatory rheological measurements, where it was found that the amount of boron in the gel has a crucial role on the occurrence of the phase transition and consequently on its acoustic performance. The passive scenario results revealed a high and dynamic absorption of approximately 80% at the absorption coefficient peaks, which dynamically shifted to lower frequencies while sound amplitudes were increased. The active noise cancellation was successfully demonstrated at the lower frequencies range, as the occurrence of the phase transition was actively controlled via the sound pressure wave introduced. The aforementioned phase transition was intensified, with energy consumed in this process, resulting in a dynamic noise cancellation. These results demonstrated that the proposed gel membrane material can be used to develop active/passive deep subwavelength absorbers with unique properties, which can dynamically tune their performance in response to external stimuli, and that can be further controlled/activated with the use of mechanical transducers.

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Section: Passive Systemmentioning

confidence: 81%

Investigation of a dynamic active/passive noise cancellation of polyborosiloxane thin membrane gel

Myronidis

Malfense-Fierro

Meo

et al. 2023

Active and Passive Smart Structures and Integrated Systems XVII

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“…2 the proposed GOHCGOHC structure metamaterial show that the unit cell of the proposed metamaterial does not behave as a single degree of freedom resonator, as the common MPP absorbers of the membrane-type metamaterial, but as multi degree of freedom resonator and the absorption broadening characteristics are then associated to multiple hybrid resonances. We demonstrated in a previous work 44 how considering the fluid–structure interaction of thin plate with the enclosed airgap, the plate does not behave as a piston system as the other membrane-type acoustic metamaterials 10 , 17 , 20 . Considering the single HC core unit cell, it acts as a senator acoustic cavity covered by the GO foil behaving as a plate fixed supported on the HC cell edges.…”

Section: Results and Commentsmentioning

confidence: 99%

Graphite-oxide hybrid multi-degree of freedom resonator metamaterial for broadband sound absorption

Bucciarelli

Fierro

Rapisarda

et al. 2022

Sci Rep

Self Cite

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Low frequency broadband sound absorption for thin structures is still a great challenge. A new concept of a stackable hybrid resonator metamaterial is proposed which exhibits super broadband low-frequency sound absorption. The proposed metamaterial is based on micrometric scale thickness Graphene Oxide (GO) embedded in a stacked structure or used as external skin in a designed honeycomb (HC) structure. The stackable nature of the proposed structure allows the GO-HC cores to be embedded within micro-perforated panels (MPP) providing enhanced stiffness/strength to the structure and high absorption characteristics. We demonstrate how the exploitation of the GO elastic and mass properties result in multiple hybrid structural–acoustic resonances. These resonances are tailored to occur in a frequency range of interest by the theoretical calculation of the sound absorption coefficient. The theoretical model combines the mutual interaction between the structural dynamic of the GO foil and acoustic higher modes of the HC core cell as well as stacked MPP-HC/GO-HC cores. The result is a multi-degree of freedom hybrid resonator which provides subwavelength scale broadband sound absorption in low frequency range between 300 and 2500 Hz.

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“…A similar situation occurred in the multilayer resonator with extended neck proposed by Guo et al [31] which realized a 550-700 Hz near-perfect sound absorption but with a thickness of 61 mm. As for the rigid-elastic composite structure, Bucciarelli et al [32] reported an application of elastic membrane on Helmholtz resonator-type absorbing material with a very low-frequency absorbing peak at around 300 Hz while with a narrow absorbing bandwidth around 200 Hz. Hou et al [33] researched the rigid MPP with an elastic backboard.…”

Section: Mechanical Performancementioning

confidence: 99%

Finite Element Analysis on Acoustic and Mechanical Performance of Flexible Perforated Honeycomb‐Corrugation Hybrid Sandwich Panel

Wang

Xie

et al. 2021

Shock and Vibration

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Since proposed, the perforated honeycomb-corrugation sandwich panel has attracted a lot of attention due to its superior broadband sound absorption at low frequencies and excellent mechanical stiffness/strength. However, most existing studies have assumed a structure made of high-strength materials and studied its performance based on the ideal rigid-wall model with little consideration for acoustic-structure interaction, thereby neglecting the structural vibrations caused by the material’s elasticity. In this paper, we developed a more realistic model considering the solid structural dynamics using the finite element method (FEM) and by applying aluminum and rubber as the structural material. The enhancement of the low-frequency performance and inhibition of broadband absorption coexisted in low-strength rubbers, implying a compromise in the selection of Young's modulus to balance these two influences. Further analysis on thermal-viscous dissipation, mechanical energy, and average structural stress indicated that the structure should work right below the resonant frequency for optimization. Based on these findings, we designed a novel aluminum-rubber composite structure possessing enhanced low-frequency absorption, high resistance to shear load, normal compression, and thermal expansion. Our research is expected to shed some light on noise control and the design of multifunctional acoustic metamaterials.

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Broadening sound absorption coefficient with hybrid resonances

Cited by 18 publications

References 22 publications

Investigation of a dynamic active/passive noise cancellation of polyborosiloxane thin membrane gel

Investigation of a dynamic active/passive noise cancellation of polyborosiloxane thin membrane gel

Graphite-oxide hybrid multi-degree of freedom resonator metamaterial for broadband sound absorption

Finite Element Analysis on Acoustic and Mechanical Performance of Flexible Perforated Honeycomb‐Corrugation Hybrid Sandwich Panel

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