A thin meta-structure with multi-order resonance for underwater broadband sound absorption in low frequency

2021 ◽  
Vol 179 ◽  
pp. 108025
Author(s):  
Li Bo Wang ◽  
Cheng Zhi Ma ◽  
Jiu Hui Wu
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Order Resonance ◽  
Broadband Sound

Highly Efficient Low‐Frequency Broadband Sound Absorption with a Composite Hybrid Metasurface

2021 ◽  
Author(s):  
Qingxuan Liang ◽  
Yutao Wu ◽  
Peiyao Lv ◽  
Jin He ◽  
Fuyin Ma ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Highly Efficient ◽  
Broadband Sound

scholarly journals Highly Efficient Low‐Frequency Broadband Sound Absorption with a Composite Hybrid Metasurface

2021 ◽  
Vol 23 (10) ◽  
pp. 2170041
Author(s):  
Qingxuan Liang ◽  
Yutao Wu ◽  
Peiyao Lv ◽  
Jin He ◽  
Fuyin Ma ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Highly Efficient ◽  
Broadband Sound

An acoustic absorbing metamaterial with multi-Helmholtz resonators at low-frequency underwater

2021 ◽  
pp. 2150397
Author(s):  
Y. Q. Luo ◽  
J. J. Lou ◽  
Y. B. Zhang
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Resonance Mode ◽  
Low Frequencies ◽  
Acoustic Metamaterial ◽  
Material Parameters ◽  
Helmholtz Resonators ◽  
Design Idea ◽  
Broadband Sound ◽  
Inversion Calculation

An ultra-thin waterborne acoustic metamaterial (AM), which is made of steel and composed of multi-Helmholtz resonators (MHRs), is proposed to achieve perfect sound absorption at low frequencies, which are generated around the resonance mode. The average surface acoustic impedance of the metamaterial is almost perfectly matched with water impedance under the action of resonance among the HRs, thus the perfect sound absorption is achieved. The case of two resonators is taken as an example to verify the design idea. By adjusting HRs’ sizes in simulation, the sound absorption coefficient reaches 99.6% at low frequency of 2740 Hz with ultra-thin thickness less than [Formula: see text]. The abnormal physical properties of AMs are often accompanied by abnormal effective material parameters, which turn to be negative near the perfect sound absorption through inversion calculation. The HRs proposed are simple to fabricate, mechanically stable, and convenient to couple with other resonators to achieve low-frequency broadband sound absorption.

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

Nonlinear behavior of Helmholtz resonator with a compliant wall for low frequency, broadband noise control

2021 ◽  
pp. 1-29
Author(s):  
Maya Pishvar ◽  
Ryan L Harne
Keyword(s):  
Dynamic Response ◽  
Low Frequency ◽  
Nonlinear Behavior ◽  
Helmholtz Resonator ◽  
Broadband Noise ◽  
Sound Attenuation ◽  
Wall Material ◽  
Modeling Framework ◽  
Compliant Wall ◽  
Broadband Sound

Abstract Low frequency sound attenuation is often pursued using Helmholtz resonators (HRs). The introduction of a compliant wall around the acoustic cavity results in a two-degree-of-freedom (2DOF) system capable of more broadband sound absorption. In this study, we report the amplitude-dependent dynamic response of a compliant walled HR and investigate the effectiveness of wall compliance to improve the absorption of sound in linear and nonlinear regimes. The acoustic-structure interactions between the conventional Helmholtz resonator and the compliant wall result in non-intuitive responses when acted on by nonlinear amplitudes of excitation pressure. This paper formulates and studies a reduced order model to characterize the nonlinear dynamic response of the 2DOF HR with a compliant wall compared to that of a conventional rigid HR. Validated by experimental evidence, the modeling framework facilitates an investigation of strategies to achieve broadband sound attenuation, including by selection of wall material, wall thickness, geometry of the HR, and other parameters readily tuned by system design. The results open up new avenues for the development of efficient acoustic resonators exploiting the deflection of a compliant wall for suppression of extreme noise amplitudes.

Realizing high-efficiency low frequency sound absorption of underwater meta-structures by acoustic siphon effect

2021 ◽  
pp. 2150319
Author(s):  
Li Bo Wang ◽  
Cheng Zhi Ma ◽  
Jiu Hui Wu ◽  
Chong Rui Liu
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
High Efficiency ◽  
Physical Mechanism ◽  
Low Frequency ◽  
Area Ratio ◽  
Underwater Acoustic ◽  
Element Simulation ◽  
Average Absorption Coefficient ◽  
New Perspective

The underwater acoustic siphon effect is proposed in this work, which aims to reveal the basic physical mechanism of high-efficiency sound absorption in meta-structures composed of multiple detuned units. Furthermore, the influence of the area ratio on the underwater acoustic siphon effect is then investigated by finite element simulation (FES) and theoretical calculation. On this basis, a meta-structure with the maximum absorption coefficient of almost 100% and average absorption coefficient of 80% at 600–1400 Hz is achieved. The underwater acoustic siphon effect could provide a better understanding of high-efficiency sound absorption and offer a new perspective in controlling underwater noises.

scholarly journals Study on the sound absorption behavior of multi-component polyester nonwovens: experimental and numerical methods

2018 ◽  
Vol 89 (16) ◽  
pp. 3342-3361 ◽  
Author(s):  
Tao Yang ◽  
Ferina Saati ◽  
Kirill V Horoshenkov ◽  
Xiaoman Xiong ◽  
Kai Yang ◽  
...  
Keyword(s):  
Numerical Methods ◽  
Absorption Coefficient ◽  
Empirical Model ◽  
Surface Impedance ◽  
Sound Absorption ◽  
Low Frequency ◽  
Accurate Method ◽  
Small Error ◽  
Sound Absorption Coefficient ◽  
Acoustical Properties

This study presents an investigation of the acoustical properties of multi-component polyester nonwovens with experimental and numerical methods. Fifteen types of nonwoven samples made with staple, hollow and bi-component polyester fibers were chosen to carry out this study. The AFD300 AcoustiFlow device was employed to measure airflow resistivity. Several models were grouped in theoretical and empirical model categories and used to predict the airflow resistivity. A simple empirical model based on fiber diameter and fabric bulk density was obtained through the power-fitting method. The difference between measured and predicted airflow resistivity was analyzed. The surface impedance and sound absorption coefficient were determined by using a 45 mm Materiacustica impedance tube. Some widely used impedance models were used to predict the acoustical properties. A comparison between measured and predicted values was carried out to determine the most accurate model for multi-component polyester nonwovens. The results show that one of the Tarnow model provides the closest prediction to the measured value, with an error of 12%. The proposed power-fitted empirical model exhibits a very small error of 6.8%. It is shown that the Delany–Bazley and Miki models can accurately predict surface impedance of multi-component polyester nonwovens, but the Komatsu model is less accurate, especially at the low-frequency range. The results indicate that the Miki model is the most accurate method to predict the sound absorption coefficient, with a mean error of 8.39%.

A multilayer microperforated panel prototype for broadband sound absorption at low frequencies

2019 ◽  
Vol 146 ◽  
pp. 134-144 ◽  
Author(s):  
F. Bucciarelli ◽  
G.P. Malfense Fierro ◽  
M. Meo
Keyword(s):  
Sound Absorption ◽  
Low Frequencies ◽  
Broadband Sound
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