A Composite Matching Layer with Anti-Reflection Characteristics for Broadband Acoustic Scattering Reduction

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Shande Li ◽  
Xiaoxun Wu ◽  
Jinxiu Duan ◽  
Shuai Yuan ◽  
Cun Wang ◽  
...  
Keyword(s):  
Theoretical Model ◽  
Metal Foam ◽  
Effective Medium Theory ◽  
Acoustic Scattering ◽  
The Finite Element Method ◽  
Medium Theory ◽  
Acoustic Reflection ◽  
Matching Layer ◽  
Variation Trends ◽  
Reflection Characteristics

A composite matching layer composed of periodically arranged scatters with anti-reflection (AR) characteristics is proposed for broadband scattering reduction. The anti-reflection structure is composed of periodically arranged metal foam scatters, and it is the first attempt to be applied in the field of suppressing acoustic reflection. A complete theoretical model is developed to reveal the mechanism of scattering reduction and acoustic absorption based on effective medium theory and the transfer matrix method. The correctness and effectiveness of the theoretical model are verified by the finite element method (FEM), showing acoustic reflectance of less than 13.5% at broadband frequencies. The variation trends of reflectance are deeply investigated. The superior acoustic scattering reduction performance suggests that the matching layer possesses potential for acoustic imaging equipment and acoustic stealth.

scholarly journals Anisotropic Photonics Topological Transition in Hyperbolic Metamaterials Based on Black Phosphorus

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1694
Author(s):  
Zengping Su ◽  
Yueke Wang
Keyword(s):  
Effective Medium Theory ◽  
Black Phosphorus ◽  
Full Width ◽  
Half Maximum ◽  
The Finite Element Method ◽  
Medium Theory ◽  
Hyperbolic Metamaterials ◽  
Topological Transition ◽  
Incident Plane ◽  
Plane Anisotropy

Based on in-plane anisotropy of black phosphorus (BP), anisotropic photonics topological transition (PTT) can be achieved by the proposed hyperbolic metamaterials structure, which is composed of alternating BP/SiO2 multilayer. Through effective medium theory and calculated iso-frequency contour, PTT can be found by carefully choosing the incident plane and other parameters. With the finite element method and transfer matrix method, a narrow angular optical transparency window with angular full width at half maximum of 1.32° exists at PTT. By changing the working wavelength, thickness of SiO2, or electron doping of black phosphorus, the incident plane of realizing PTT can be modulated, and anisotropic PTT is achieved.

Effective medium theory and the attenuation of graphite fiber composites

1993 ◽  
Vol 73 (7) ◽  
pp. 3441-3445 ◽  
Author(s):  
Herbert Überall ◽  
Barbara F. Howell ◽  
Earl L. Diamond
Keyword(s):  
Effective Medium Theory ◽  
Fiber Composites ◽  
Effective Medium ◽  
Graphite Fiber ◽  
Medium Theory

From the Huckel model to effective-medium theory

1991 ◽  
Vol 3 (40) ◽  
pp. 7757-7762 ◽  
Author(s):  
H Hakkinen ◽  
J Mansikka-aho ◽  
M Manninen
Keyword(s):  
Effective Medium Theory ◽  
Effective Medium ◽  
Medium Theory
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