An experimental study on the optimization of the production and efficiency of tunable Helmholtz absorbers for the modal control of small rooms

Thomazelli, Rodolfo; Bertoli, Stelamaris Rolla

doi:10.1177/1351010x19829870

Cited by 3 publications

(1 citation statement)

References 25 publications

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“…However, the analytical model used in these studies consists of a typical MPP and a rigid back wall coupled to an acoustic enclosure. Thomazelli and Bertoli 50 investigated a potential alternative to optimize the production and development of a tunable MPP absorber capable of changing its geometrical configurations in response to the acoustic requirements of each room.…”

Section: Introductionmentioning

confidence: 99%

Vibroacoustic analysis of multi-layered micro-perforated plates coupled to an acoustic enclosure

2023

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A vibroacoustic study of multi-layered micro-perforated plates (MPP) coupled to an enclosure cavity excited by internal and external acoustic excitations is presented. Most previous research centered on the multi-layered MPPs structure itself, the absorption and transmission performances were often calculated or tested in a simple acoustic environment. In a more realistic setting, the surrounding systems may affect the efficiency of MPPs. The proper modeling of the MPPs within acoustic enclosures requires careful study. The break-out sound from an enclosure via multi-layered MPP and the energy transmission of the structure into an acoustic enclosure undergoing exterior excitation are studied with an emphasis on the use of MPP in acoustic enclosures to suppress specific resonances of the enclosure. Therefore, an analytical formulation is proposed to model the behavior of the coupled system to address this issue. Using a modified Fourier series for the acoustic pressure, the continuity of the normal velocities at the interfaces of the plate or the MPP and the acoustic medium is assured accurately. A modified variational form for the acoustic and structure medium yields a completely coupled vibroacoustic system. Comparison with the finite element method (FEM) and available literature findings prove the efficacy and precision of the current approach. The effect of important parameters on the vibroacoustic behavior of multi-layered MPPs structure connected to an acoustic enclosure is examined. These parameters include micro-perforation of the plate, hole diameter, air gap thickness, acoustic enclosure dimensions, and the insertion of absorbent material in the gap.

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Section: Introductionmentioning

confidence: 99%

Vibroacoustic analysis of multi-layered micro-perforated plates coupled to an acoustic enclosure

2023

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Wettability and sound absorption of graphene oxide doped polymer hydrogel

Khosrozadeh

Rasuli

Hamzeloopak

et al. 2021

Sci Rep

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In this paper, we introduce a nanocomposite as a humidity-sensitive sound absorber. The nanocomposites were prepared using hydrogel polymer (HP) as a matrix and graphene oxide (GO) as a filler. Results show that the surface energy of the nanocomposite is 58.4 mJ m−2, and GO sheets increase the nanocomposite porosity from 2.6716 cm2 g−1 (for HP) up to 3.246 cm2 g−1. In addition, the diameter of nanocomposite pores is 8.5202 nm lower than that of HP (10.274 nm). To study the effect of humidity on the sound absorption, we exposed them to moisture for 30 and 60 min and then measured sound absorption. Results show an absorption peak for the HP at 1022 Hz with an attenuation value of 30%, while the nanocomposite shows two main peaks around 1898 and 3300 Hz. In addition, results show that sound absorption peaks shift to higher frequencies according to humidification time.

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Graphene Oxide–Polymer Hydrogel: Wettability and Sound Absorption

Khosrozadeh

Rasuli

Hamzeloopak

et al. 2021

Preprint

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In this paper, we introduce a nanocomposite as a humidity-sensitive sound absorber. The nanocomposites were prepared using hydrogel polymer (HP) as a matrix and graphene oxide (GO) as a filler. Results show that the surface energy of the nanocomposite is 58.4 mJm-2, and GO sheets increase the nanocomposite porosity from 2.6716 cm2 g-1 (for HP) up to 3.246 cm2 g-1. In addition, the diameter of nanocomposite pores is 8.5202 nm lower than that of HP (10.274 nm). To study the effect of humidity on the sound absorption, we exposed them to moisture for 30 and 60 min and then measured sound absorption. Results show an absorption peak for the HP at 1022 Hz with an attenuation value of 30%, while nanocomposite shows two main peaks around 1898 and 3300 Hz. In addition, results show that sound absorption peaks shift to higher frequency according to humidification time.

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An experimental study on the optimization of the production and efficiency of tunable Helmholtz absorbers for the modal control of small rooms

Cited by 3 publications

References 25 publications

Vibroacoustic analysis of multi-layered micro-perforated plates coupled to an acoustic enclosure

Vibroacoustic analysis of multi-layered micro-perforated plates coupled to an acoustic enclosure

Wettability and sound absorption of graphene oxide doped polymer hydrogel

Graphene Oxide–Polymer Hydrogel: Wettability and Sound Absorption

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