Vibrational relaxation rates in N2/CO2 mixtures as determined from low‐frequency sound absorption measurements

1980 ◽  
Vol 68 (4) ◽  
pp. 1210-1212 ◽  
Author(s):  
F. Douglas Shields ◽  
H. E. Bass
Keyword(s):  
Vibrational Relaxation ◽  
Sound Absorption ◽  
Low Frequency ◽  
Relaxation Rates ◽  
Frequency Sound ◽  
Absorption Measurements

Low frequency sound absorption of adjustable membrane-type acoustic metamaterials

2022 ◽  
Vol 188 ◽  
pp. 108586
Author(s):  
Tuo Xing ◽  
Xiaoling Gai ◽  
Junjuan Zhao ◽  
Xianhui Li ◽  
Zenong Cai ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Acoustic Metamaterials ◽  
Frequency Sound ◽  
Membrane Type

A double porosity material for low frequency sound absorption

2020 ◽  
Vol 239 ◽  
pp. 111978 ◽  
Author(s):  
Honggang Zhao ◽  
Yang Wang ◽  
Dianlong Yu ◽  
Haibin Yang ◽  
Jie Zhong ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Low Frequency ◽  
Double Porosity ◽  
Frequency Sound

scholarly journals Hybrid acoustic metamaterial as super absorber for broadband low-frequency sound

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Yufan Tang ◽  
Shuwei Ren ◽  
Han Meng ◽  
Fengxian Xin ◽  
Lixi Huang ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Absorption Coefficient ◽  
Sound Absorption ◽  
Low Frequency ◽  
Functional Materials ◽  
Theoretical Method ◽  
Acoustic Metamaterials ◽  
Mechanical Stiffness ◽  
Acoustic Metamaterial ◽  
Frequency Sound

Abstract A hybrid acoustic metamaterial is proposed as a new class of sound absorber, which exhibits superior broadband low-frequency sound absorption as well as excellent mechanical stiffness/strength. Based on the honeycomb-corrugation hybrid core (H-C hybrid core), we introduce perforations on both top facesheet and corrugation, forming perforated honeycomb-corrugation hybrid (PHCH) to gain super broadband low-frequency sound absorption. Applying the theory of micro-perforated panel (MPP), we establish a theoretical method to calculate the sound absorption coefficient of this new kind of metamaterial. Perfect sound absorption is found at just a few hundreds hertz with two-octave 0.5 absorption bandwidth. To verify this model, a finite element model is developed to calculate the absorption coefficient and analyze the viscous-thermal energy dissipation. It is found that viscous energy dissipation at perforation regions dominates the total energy consumed. This new kind of acoustic metamaterials show promising engineering applications, which can serve as multiple functional materials with extraordinary low-frequency sound absorption, excellent stiffness/strength and impact energy absorption.

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