scholarly journals Low-Frequency, Open, Sound-Insulation Barrier by Two Oppositely Oriented Helmholtz Resonators

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1544
Author(s):  
Yi-Jun Guan ◽  
Yong Ge ◽  
Hong-Xiang Sun ◽  
Shou-Qi Yuan ◽  
Xiao-Jun Liu
Keyword(s):  
High Performance ◽  
Low Frequency ◽  
Single Layer ◽  
Sound Insulation ◽  
Architectural Acoustics ◽  
Frequency Sound ◽  
Helmholtz Resonators ◽  
Viscous Loss ◽  
Insulation Effect ◽  
Broadband Sound

In this work, a low-frequency, open, sound-insulation barrier, composed of a single layer of periodic subwavelength units (with a thickness of λ/28), is demonstrated both numerically and experimentally. Each unit was constructed using two identical, oppositely oriented Helmholtz resonators, which were composed of a central square cavity surrounded by a coiled channel. In the design of the open barrier, the distance between two adjacent units was twice the width of the unit, showing high-performance ventilation, and low-frequency sound insulation. A minimum transmittance of 0.06 could be observed around 121.5 Hz, which arose from both sound reflections and absorptions, created by the coupling of symmetric and asymmetric eigenmodes of the unit, and the absorbed sound energy propagating into the central cavity was greatly reduced by the viscous loss in the channel. Additionally, by introducing a multilayer open barrier, a broadband sound insulation was obtained, and the fractional bandwidth could reach approximately 0.19 with four layers. Finally, the application of the multilayer open barrier in designing a ventilated room was further discussed, and the results presented an omnidirectional, broadband, sound-insulation effect. The proposed open, sound-insulation barrier with the advantages of ultrathin thickness; omnidirectional, low-frequency sound insulation; broad bandwidth; and high-performance ventilation has great potential in architectural acoustics and noise control.

scholarly journals Study on broadband low-frequency sound insulation of multi-channel resonator acoustic metamaterials

AIP Advances ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 045321
Author(s):  
Chi Xu ◽  
Hui Guo ◽  
Yinghang Chen ◽  
Xiaori Dong ◽  
Hongling Ye ◽  
...  
Keyword(s):  
Low Frequency ◽  
Sound Insulation ◽  
Acoustic Metamaterials ◽  
Frequency Sound

Ventilated metamaterials for broadband sound insulation and tunable transmission at low frequency

2021 ◽  
pp. 101348
Author(s):  
Zhenqian Xiao ◽  
Penglin Gao ◽  
Dongwei Wang ◽  
Xiao He ◽  
Linzhi Wu
Keyword(s):  
Low Frequency ◽  
Sound Insulation ◽  
Broadband Sound

Numerical study for increasement of low frequency sound insulation of double-panel structure using sonic crystals with distributed Helmholtz resonators

2019 ◽  
Vol 33 (14) ◽  
pp. 1950138
Author(s):  
Myong-Jin Kim
Keyword(s):  
Free Space ◽  
Transmission Loss ◽  
Numerical Study ◽  
Low Frequency ◽  
Helmholtz Resonator ◽  
Sound Insulation ◽  
The Finite Element Method ◽  
Helmholtz Resonators ◽  
Sonic Crystal ◽  
Sonic Crystals

Numerical simulations of the sound transmission loss (STL) of a double-panel structure (DPS) with sonic crystal (SC) comprised of distributed local resonators are presented. The Local Resonant Sonic Crystal (LRSC) consists of “C”-shaped Helmholtz resonator columns with different resonant frequencies. The finite element method is used to calculate the STL of such a DPS. First, the STLs of LRSC in free space and the DPS with LRSC are calculated and compared. It is shown that the sound insulations of the local resonators inserted in the double panel are higher than that in free space for the same size of the SCs and the same number of columns. Next, STL of the DPS in which the SC composed of three columns of local resonators having the same outer and inner diameters but different slot widths are calculated, and a reasonable arrangement order is determined. Finally, the soundproofing performances of DPS with distributed LRSC are compared with the case of insertion of general cylindrical SC for SC embedded in glass wool and not. The results show that the sound insulation of the DPS can be significantly improved in the low frequency range while reducing the total mass without increasing the thickness.

scholarly journals Fractal Acoustic Metamaterials with Subwavelength and Broadband Sound Insulation

2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Yu Liu ◽  
Meng Chen ◽  
Wenshuai Xu ◽  
Tao Yang ◽  
Dongliang Pei ◽  
...  
Keyword(s):  
Low Frequency ◽  
Sound Insulation ◽  
Acoustic Metamaterials ◽  
The Finite Element Method ◽  
Transmission Losses ◽  
Effective Parameters ◽  
Retrieval Method ◽  
Sound Control ◽  
S Parameter ◽  
Broadband Sound

We construct new fractal acoustic metamaterials by coiling up space, which can allow subwavelength-scale and broadband sound insulation to be achieved. Using the finite element method and the S-parameter retrieval method, the band structures, the effective parameters, and the transmission losses of these acoustic metamaterials with different fractal orders are researched individually. The results illustrate that it is easy to form low-frequency bandgaps using these materials and thus achieve subwavelength-scale sound control. As the number of fractal orders increase, more bandgaps appear. In particular, in the ΓX direction of the acoustic metamaterial lattice, more of these wide bandgaps appear in different frequency ranges, thus providing broadband sound insulation and showing promise for use in engineering applications.

scholarly journals A lightweight low-frequency sound insulation membrane-type acoustic metamaterial

AIP Advances ◽  
2016 ◽  
Vol 6 (2) ◽  
pp. 025116 ◽  
Author(s):  
Kuan Lu ◽  
Jiu Hui Wu ◽  
Dong Guan ◽  
Nansha Gao ◽  
Li Jing
Keyword(s):  
Low Frequency ◽  
Sound Insulation ◽  
Acoustic Metamaterial ◽  
Frequency Sound ◽  
Membrane Type

Design of efficient low-frequency sound absorbers using an array of Helmholtz Resonators

2020 ◽  
Vol 148 (4) ◽  
pp. 2798-2799
Author(s):  
Vidhya Rajendran ◽  
Tomás I. Méndez Echenagucia ◽  
Andrew A. Piacsek
Keyword(s):  
Low Frequency ◽  
Frequency Sound ◽  
Helmholtz Resonators

Low frequency sound insulation performance of asymmetric coupled-membrane acoustic metamaterials

2019 ◽  
Vol 15 (5) ◽  
pp. 1006-1015
Author(s):  
Mengna Cai ◽  
Hongyan Tian ◽  
Haitao Liu ◽  
Yanhui Qie
Keyword(s):  
Low Frequency ◽  
Sound Insulation ◽  
Asymmetric Structure ◽  
Insulation Material ◽  
Metamaterial Structure ◽  
Content Type ◽  
Acoustic Metamaterial ◽  
Frequency Sound ◽  
Membrane Type ◽  
Insulation Performance

Purpose With the development of the modern technology and aerospace industry, the noise pollution is remarkably affecting people’s daily life and has been become a serious issue. Therefore, it is the most important task to develop efficient sound attenuation barriers, especially for the low-frequency audible range. However, low-frequency sound attenuation is usually difficult to achieve for the constraints of the conventional mass-density law of sound transmission. The traditional acoustic materials are reasonably effective at high frequency range. This paper aims to discuss this issue. Design/methodology/approach Membrane-type local resonant acoustic metamaterial is an ideal low-frequency sound insulation material for its structure is simple and lightweight. In this paper, the finite element method is used to study the low-frequency sound insulation performances of the coupled-membrane type acoustic metamaterial (CMAM). It consists of two identical tensioned circular membranes with fixed boundary. The upper membrane is decorated by a rigid platelet attached to the center. The sublayer membrane is attached with two weights, a central rigid platelet and a concentric ring with inner radius e. The influences of the distribution and number of the attached mass, also asymmetric structure on the acoustic attenuation characteristics of the CMAM, are discussed. Findings In this paper, the acoustic performance of asymmetric coupled-membrane metamaterial structure is discussed. The influences of mass number, the symmetric and asymmetry structure on the sound insulation performance are analyzed. It is shown that increasing the number of mass attached on membrane, structure exhibits low-frequency and multi-frequency acoustic insulation phenomenon. Compared with the symmetrical structure, asymmetric structure shows the characteristics of lightweight and multi-frequency sound insulation, and the sound insulation performance can be tuned by adjusting the distribution mode and location of mass blocks. Originality/value Membrane-type local resonant acoustic metamaterial is an ideal low-frequency sound insulation material for its structure is simple and lightweight. How to effectively broaden the acoustic attenuation band at low frequency is still a problem. But most of researchers focus on symmetric structures. In this study, the asymmetric coupled-membrane acoustic metamaterial structure is examined. It is demonstrated that the asymmetric structure has better sound insulation performances than symmetric structure.

scholarly journals Low-Frequency Broadband Sound Transmission Loss of Infinite Orthogonally Rib-Stiffened Sandwich Structure with Periodic Subwavelength Arrays of Shunted Piezoelectric Patches

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Zhifu Zhang ◽  
Weiguang Zheng ◽  
Qibai Huang
Keyword(s):  
Sandwich Structure ◽  
Transmission Loss ◽  
Virtual Work ◽  
Low Frequency ◽  
Sound Transmission ◽  
Sound Insulation ◽  
Convergence Criterion ◽  
Sound Transmission Loss ◽  
Space Harmonic ◽  
Broadband Sound

This paper studies low-frequency sound transmission loss (STL) of an infinite orthogonally rib-stiffened sandwich structure flexibly connected with periodic subwavelength arrays of finite shunted piezoelectric patches. A complete theoretical model is proposed by three steps. First, the panels and piezoelectric patches on both sides are equivalent to two homogeneous facesheets by effective medium method. Second, we take into account all inertia terms of the rib-stiffeners to establish the governing equations by space harmonic method, separating the amplitude coefficients of the equivalent facesheets through virtual work principle. Third, the expression of STL is reduced. Based on the two prerequisites of subwavelength assumption and convergence criterion, the accuracy and validity of the model are verified by finite element simulations, cited experiments, and theoretical values. In the end, parameters affecting the STL performance of the structure are studied. All of these results show that the sandwich structure can improve the low-frequency STL effectively and broaden the sound insulation bandwidth.

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