scholarly journals Low-frequency acoustic absorption of viscoelastic coating with various shapes of scatterers

2012 ◽  
Vol 61 (21) ◽  
pp. 214302
Author(s):  
Lyu Lin-Mei ◽  
Wen Ji-Hong ◽  
Zhao Hong-Gang ◽  
Meng Hao ◽  
Wen Xi-Sen
Keyword(s):  
Low Frequency ◽  
Acoustic Absorption

Low-frequency sound absorption of a tunable multilayer composite structure

2021 ◽  
pp. 107754632110082
Author(s):  
Hanbo Shao ◽  
Jincheng He ◽  
Jiang Zhu ◽  
Guoping Chen ◽  
Huan He
Keyword(s):  
Porous Material ◽  
Absorption Coefficient ◽  
Composite Structure ◽  
Low Frequency ◽  
Acoustic Absorption ◽  
Multilayer Composite ◽  
Absorption Frequency ◽  
Acoustic Absorption Coefficient ◽  
Simulation And Experiment ◽  
Single Material

Our work investigates a tunable multilayer composite structure for applications in the area of low-frequency absorption. This acoustic device is comprised of three layers, Helmholtz cavity layer, microperforated panel layer, and the porous material layer. For the simulation and experiment in our research, the absorber can fulfill a twofold requirement: the acoustic absorption coefficient can reach near 0.8 in very low frequency (400 Hz) and the range of frequency is very wide (400–3000 Hz). In all its absorption frequency, the average of the acoustic absorption coefficient is over 0.9. Besides, the absorption coefficient can be tunable by the scalable cavity. The multilayer composite structure in our article solved the disadvantages in single material. For example, small absorption coefficient in low frequency in traditional material such as microperforated panel and porous material and narrow reduction frequency range in acoustic metamaterial such as Helmholtz cavity. The design of the composite structure in our article can have more wide application than single material. It can also give us a novel idea to produce new acoustic devices.

Low Frequency Absorption of Additively Manufactured Cylinders

2019 ◽  
Author(s):  
Sophie R. Kaye ◽  
Ethan D. Casavant ◽  
Paul E. Slaboch
Keyword(s):  
Low Frequency ◽  
Normal Incidence ◽  
Frequency Noise ◽  
Outer Diameter ◽  
Acoustic Absorption ◽  
Frequency Range ◽  
Large Space ◽  
Low Frequencies ◽  
Cylinder Length ◽  
Hollow Cylinders

Abstract Attenuating low frequencies is often problematic, due to the large space required for common absorptive materials to mitigate such noise. However, natural hollow reeds are known to effectively attenuate low frequencies while occupying relatively little space compared to traditional absorptive materials. This paper discusses the effect of varied outer diameter, and outer spacing on the 200–1600 Hz acoustic absorption of additively manufactured arrays of hollow cylinders. Samples were tested in a 10 cm diameter normal incidence impedance tube such that cylinder length was oriented perpendicular to the incoming plane wave. By varying only one geometric element of each array, the absorption due to any particular parameter can be assessed individually. The tests confirmed the hypothesis that minimizing cylinder spacing and maximizing cylinder diameter resulted in increased overall absorption and produced more focused absorption peaks at specific low frequencies. Wider cylinder spacing produced a broader absorptive frequency range, despite shifting upward in frequency. Thus, manipulating these variables can specifically target absorption for low frequency noise that would otherwise disturb listeners.

scholarly journals Low-frequency acoustic absorption mechanism of a viscoelastic layer with resonant cylindrical scatterers

2013 ◽  
Vol 62 (15) ◽  
pp. 154301
Author(s):  
Yang Hai-Bin ◽  
Li Yue ◽  
Zhao Hong-Gang ◽  
Wen Ji-Hong ◽  
Wen Xi-Sen
Keyword(s):  
Low Frequency ◽  
Viscoelastic Layer ◽  
Acoustic Absorption ◽  
Absorption Mechanism

Engineering Coiling‐Up Space Metasurfaces for Broadband Low‐Frequency Acoustic Absorption

2019 ◽  
Vol 13 (12) ◽  
pp. 1900426 ◽  
Author(s):  
Shuang Chen ◽  
Yuancheng Fan ◽  
Fan Yang ◽  
Yabin Jin ◽  
Quanhong Fu ◽  
...  
Keyword(s):  
Low Frequency ◽  
Acoustic Absorption

Low-Frequency Acoustic Absorption of 3D Printed Cylinders

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Paul E. Slaboch ◽  
Sophie Kaye ◽  
Ethan Casavant
Keyword(s):  
Low Frequency ◽  
Normal Incidence ◽  
Frequency Noise ◽  
Outer Diameter ◽  
Acoustic Absorption ◽  
Large Space ◽  
Low Frequencies ◽  
Cylinder Length ◽  
3D Printed ◽  
Hollow Cylinders

Abstract Attenuating low-frequency sound is often problematic, due to the large space required for common absorptive materials to mitigate such noise. However, natural hollow reeds are known to effectively attenuate low frequencies while occupying relatively little space compared to traditional absorptive materials. The present study determines the effect of varied outer diameter and outer spacing on the 200–1600 Hz acoustic absorption of 3D printed arrays of hollow cylinders. Samples were tested in a 100-mm diameter normal incidence impedance tube such that cylinder length was oriented perpendicular to the incoming plane wave. By varying only one geometric element of each array, the absorption due to any parameter can be assessed individually. It was found that minimizing cylinder spacing and maximizing cylinder diameter resulted in increased overall absorption and produced more focused absorption peaks at specific low frequencies. Wider cylinder spacing produced a broader absorptive frequency range, despite shifting upward in frequency. Thus, manipulating these variables can specifically target absorption for low-frequency noise that would otherwise disturb listeners.

Novel implementation of natural fibro-granular materials as acoustic absorbers

2018 ◽  
Vol 49 (9-10) ◽  
pp. 311-316 ◽  
Author(s):  
Hasina Mamtaz ◽  
Mohammad Hosseini Fouladi ◽  
Satesh Narayana Namasivayam ◽  
Saadman H Sayed ◽  
Tahani H Sayed ◽  
...  
Keyword(s):  
Granular Materials ◽  
Significant Contribution ◽  
Low Frequency ◽  
Frequency Region ◽  
Acoustic Absorption ◽  
Granular Composite ◽  
Absorption Performance ◽  
Predicted Values ◽  
Analytical Tools ◽  
Good Agreement

In this study, a new innovative fibro-granular composite was prepared as a natural acoustic material by combining fibrous and granular materials. Delany–Bazley model and Biot–Allard techniques were utilized to estimate the absorption coefficient of the developed composite material. The predicted values were validated through an analytical outcome employing Johnson–Champoux–Allard technique and an experimentally measured value which were conducted in an impedance tube. The outcomes showed the reflection of the good agreement between the analytical and experimental methods. The current research concluded that the introduction of granular materials provides significant contribution in enhancing the surface area within the composite, thereby achieving a promising acoustic absorption in the low-frequency region which is below 1 kHz. In addition, the current research also reports that, like Johnson–Champoux–Allard model, Delany–Bazley and Biot–Allard models are also two efficient analytical tools for predicting the significant low-frequency acoustic absorption performance of a fibro-granular composite.

Effects of core position of locally resonant scatterers on low-frequency acoustic absorption in viscoelastic panel

2015 ◽  
Vol 24 (8) ◽  
pp. 084301 ◽  
Author(s):  
Jie Zhong ◽  
Ji-Hong Wen ◽  
Hong-Gang Zhao ◽  
Jian-Fei Yin ◽  
Hai-Bin Yang
Keyword(s):  
Low Frequency ◽  
Acoustic Absorption
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