Novel properties of wave propagations in sonic-crystal wave-guides made of air cylinders in agar-gel - comparison with other sonic crystals and photonic crystals

2003 ◽  
Author(s):  
T. Miyashita
Keyword(s):  
Photonic Crystals ◽  
Agar Gel ◽  
Sonic Crystal ◽  
Wave Guides ◽  
Sonic Crystals

Square-root-like higher-order topological states in three-dimensional sonic crystals

2021 ◽  
Author(s):  
Zhiguo Geng ◽  
Huanzhao Lv ◽  
Zhan Xiong ◽  
Yu-Gui Peng ◽  
Zhaojiang Chen ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Surface States ◽  
Higher Order ◽  
Square Root ◽  
Root Lattice ◽  
Third Order ◽  
Topological Materials ◽  
Topological States ◽  
Sonic Crystal ◽  
Sonic Crystals

Abstract The square-root descendants of higher-order topological insulators were proposed recently, whose topological property is inherited from the squared Hamiltonian. Here we present a three-dimensional (3D) square-root-like sonic crystal by stacking the 2D square-root lattice in the normal (z) direction. With the nontrivial intralayer couplings, the opened degeneracy at the K-H direction induces the emergence of multiple acoustic localized modes, i.e., the extended 2D surface states and 1D hinge states, which originate from the square-root nature of the system. The square-root-like higher order topological states can be tunable and designed by optionally removing the cavities at the boundaries. We further propose a third-order topological corner state in the 3D sonic crystal by introducing the staggered interlayer couplings on each square-root layer, which leads to a nontrivial bulk polarization in the z direction. Our work sheds light on the high-dimensional square-root topological materials, and have the potentials in designing advanced functional devices with sound trapping and acoustic sensing.

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.

Parametric Study on Rectangular Sonic Crystal

2012 ◽  
Vol 152-154 ◽  
pp. 281-286 ◽  
Author(s):  
Arpan Gupta ◽  
Kian Meng Lim ◽  
Chye Heng Chew
Keyword(s):  
Band Gap ◽  
Periodic Structure ◽  
Parametric Study ◽  
Sound Propagation ◽  
Periodic Structures ◽  
Sound Attenuation ◽  
Experimental Results ◽  
Center Frequency ◽  
Sonic Crystal ◽  
Sonic Crystals

Sonic crystals are periodic structures made of sound hard scatterers which attenuate sound in a range of frequencies. For an infinite periodic structure, this range of frequencies is known as band gap, and is determined by the geometric arrangement of the scatterers. In this paper, a parametric study on rectangular sonic crystal is presented. It is found that geometric spacing between the scatterers in the direction of sound propagation affects the center frequency of the band gap. Reducing the geometric spacing between the scatterers in the direction perpendicular to the sound propagation helps in better sound attenuation. Such rectangular arrangement of scatterers gives better sound attenuation than the regular square arrangement of scatterers. The model for parametric study is also supported by some experimental results.

A Parametric Sonic Crystal Modal Analysis Using Finite Element Modeling

2004 ◽  
Author(s):  
Alan C. Leung ◽  
Peter Matic ◽  
Pier Paolo Delsanto ◽  
Martin Hirsekorn
Keyword(s):  
Finite Element ◽  
Single Cell ◽  
Matrix Material ◽  
Mode Shapes ◽  
Property Variation ◽  
Acoustic Damping ◽  
Acoustic Resonators ◽  
Potential Applications ◽  
Sonic Crystal ◽  
Sonic Crystals

Sonic crystals are typically materials with millimeter scale arrays of acoustic resonators embedded in a matrix material. They provide sound attenuation in acoustic band gaps at frequencies approximately two orders of magnitude lower than those predicted by Bragg’s theory of reflection. There are many potential applications of sonic crystals as filters and frequency selective acoustic damping devices. Performance characteristics of single-cell and double cell based sonic crystal structures were computationally evaluated using finite element methods. In this work, the sonic crystal consisted of cylinder inclusions encased in a soft polymer coating and embedded in a block of epoxy matrix material. Parametric studies were performed to evaluate the effects of material properties of the inclusion, coating and matrix. Mode shapes were determined. A preliminary comparison with Local Interaction Simulation Approach (LISA) is presented. The influence of material property variation, without changing geometric features, on single-cell and double-cell sonic crystal performance is discussed.

Sonic crystals and sonic wave-guides

2005 ◽  
Vol 16 (5) ◽  
pp. R47-R63 ◽  
Author(s):  
Toyokatsu Miyashita
Keyword(s):  
Sonic Wave ◽  
Wave Guides ◽  
Sonic Crystals

Numerical Studies on Band-Gap Structures and Resonant-Mode Wave-Guides of Typical Sonic Crystals Made of Rigid Cylinders in Fluid by Means of Elastic FDTD Method

2005 ◽  
Author(s):  
Toyokatsu Miyashita
Keyword(s):  
Band Gap ◽  
Fdtd Method ◽  
Transmission Band ◽  
Resonant Mode ◽  
Mode Wave ◽  
Periodic Arrays ◽  
Sonic Crystal ◽  
Wave Guides ◽  
Periodic Repetition ◽  
Fdtd Methods

We have investigated band-gap structures of three typical sonic/phononic crystals, namely periodic arrays of methacrylic resin cylinders in air, aluminum cylinders in air, and steel cylinders in water, by two different FDTD methods; one method is a sonic one that deals with only longitudinal waves, and the other is an elastic one that includes also shear waves. We show that both FDTD methods give almost the same band-gap structures for the former two crystals. Namely, the band-gaps by the sonic FDTD method lie at higher frequency only by 0.01 ~ 0.02 in the normalized frequency than those by the elastic one. The theoretical band-gap structures agree well with the experimental ones. In contrast, it is shown that the third crystal should be analyzed by the elastic FDTD method. Resonant-mode wave-guides are made by a periodic repetition of single-defects along a line in a sonic crystal of rigid cylinders in air. The obtained resonant and well-guided transmission band lies inside the full band-gap of the original bulk crystal. A combination of such wave-guides with a line-defect wave-guide is shown to have desirable characteristics for filtered wave-guides and wave-couplers.

Band Structure in a Sustainable Sonic Crystal

2019 ◽  
Vol 958 ◽  
pp. 75-80
Author(s):  
Edson Jansen Pedrosa Miranda Jr. ◽  
S.F. Rodrigues ◽  
J.M.C. dos Santos
Keyword(s):  
Band Structure ◽  
Cross Section ◽  
Cross Sections ◽  
Acoustic Waves ◽  
Band Gaps ◽  
Square Lattice ◽  
Host Medium ◽  
Fiber Cross Section ◽  
Sonic Crystal ◽  
Sonic Crystals

During the last few decades many researchers have been interested in acoustic wave propagation in artificial periodic composites known as sonic crystals. Sonic crystals have received renewed attention because they exhibit acoustic band gaps where there are only evanescent waves. Sonic crystals consist of a periodic array of scatterers embedded in a host medium. The host medium and/or scatterers are fluids. We investigate the band structure of acoustic waves propagating in a sustainable sonic crystal composed by miriti fibers and air, regarding square and triangular lattices. Miriti fibers are extracted from buriti palm petiole (Mauritia flexuosa Mart.), which is a typical specie that grows in Amazonian region. We also study the influence of miriti fiber cross section, i.e. circular, hollow circular, square and rotated square with a 45° angle of rotation with respect to x, y axes. Plane wave expansion method is used to solve the wave equation. Acoustic band gaps are observed for all miriti fiber cross sections and lattices. The best performances of the sustainable sonic crystal are for triangular lattice, regarding circular and rotated square miriti fiber cross sections, and for square lattice with circular miriti fiber cross section. We suggest that the sustainable sonic crystal should be feasible for noise management.

Acoustical Study of a Lossy Gradient-Based Sonic Crystal Using Acoustic Beamforming

2021 ◽  
Author(s):  
Debasish Panda ◽  
Amiya Ranjan Mohanty
Keyword(s):  
Acoustic Waves ◽  
Periodic Structures ◽  
Fast Method ◽  
Fe Method ◽  
Helmholtz Resonators ◽  
Sonic Crystal ◽  
Gradient Based ◽  
Acoustical Study ◽  
Tunable Frequency ◽  
Sonic Crystals

Sonic crystals (SCs) are unique periodic structures designed to attenuate acoustic waves in tunable frequency bands known as bandgaps. Though previous works on conventional uniform SCs show good insertion loss (IL) inside the bandgaps, this work is focused on widening their bandgaps and achieving better IL inside the bandgaps by using a gradient-based sonic crystal (GBSC). The GBSC applies property gradient to the conventional SC array by varying its basic properties, i.e., the distance between the scatterers/resonators (lattice constant), and resonator dimensions between the columns and hence the name GBSC. The design of the GBSC is backed by the results of acoustic beamforming experiments conducted over the uniform SCs of hollow scatterers and Helmholtz resonators (HRs) having two-dimensional (2D) periodicity prepared by using Polyvinyl chloride (PVC) pipes without any property gradient and their respective 2D finite element (FE) studies. The experimental and FE simulation results of the uniform SCs were found to be in good agreement and therefore, the GBSC was modeled and analyzed using FE method considering the viscothermal losses inside the resonators. The results indicated that the property gradient improves both Bragg scattering and Helmholtz resonance compared to that of the uniform SCs and therefore, the GBSC exhibits wider attenuation gaps and higher attenuation levels. An array of 30 microphones was used to conduct acoustic beamforming experiments on the uniform SCs. Beamforming was found to be an advanced and fast method to perform quick measurements on the SCs.

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