Light-Driven Acoustic Band Gap Based on Metal Nanospheres

2009 ◽  
Vol 74 ◽  
pp. 17-20 ◽  
Author(s):  
Jiu Hui Wu ◽  
Boris Luk’yanchuk ◽  
Hua Ling Chen ◽  
Ai Qun Liu
Keyword(s):  
Band Gap ◽  
Acoustic Waves ◽  
Van Der Waals ◽  
Low Frequency ◽  
Optical Force ◽  
Potential Applications ◽  
Incident Laser Intensity ◽  
Metal Materials ◽  
Optical Distribution ◽  
Gap Width

In this paper, light-driven acoustic band gap is presented by considering two metal nanospheres illuminated simultaneously by laser and acoustic waves. The interaction between the photonics and phonons is investigated through optical distribution force, van der Waals distribution force, and acoustic pressure upon these nanospheres. Based on the optical force and van der Waals force, the acoustic form functions for the metal nanoaggregates with different optical intensity are calculated, and the light-driven acoustics band gap at low frequency band has been found. It is shown that the band gap width can be widened with increasing the incident laser intensity, or by using proper metal materials and background media. This could provide potential applications in optical nanoswitches and acoustical filters.

scholarly journals Tunable Low Frequency Band Gap and Waveguide of Phononic Crystal Plates with Different Filling Ratio

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 828
Author(s):  
Shaobo Zhang ◽  
Jiang Liu ◽  
Hongbo Zhang ◽  
Shuliang Wang
Keyword(s):  
Band Gap ◽  
Composite Structure ◽  
Structural Parameters ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Filling Ratio ◽  
Height Ratio ◽  
Road Vehicles ◽  
Aluminum Base ◽  
Gap Width

Aiming at solving the NVH problem in vehicles, a novel composite structure is proposed. The new structure uses a hollow-stub phononic-crystal with filled cylinders (HPFC) plate. Any unit in the plate consists of a lead head, a silicon rubber body, an aluminum base as outer column and an opposite arranged inner pole. The dispersion curves are investigated by numerical simulations and the influences of structural parameters are discussed, including traditional hollow radius, thickness, height ratio, and the new proposed filling ratio. Three new arrays are created and their spectrum maps are calculated. In the dispersion simulation results, new branches are observed. The new branches would move towards lower frequency zone and the band gap width enlarges as the filling ratio decreases. The transmission spectrum results show that the new design can realize three different multiplexing arrays for waveguides and also extend the locally resonant sonic band gap. In summary, the proposed HPFC structure could meet the requirement for noise guiding and filtering. Compared to a traditional phononic crystal plate, this new composite structure may be more suitable for noise reduction in rail or road vehicles.

Broadband low-frequency acoustic absorber based on a metaporous composite

2022 ◽  
Author(s):  
Jia-Hao Xu ◽  
Xing-Feng Zhu ◽  
Di-Chao Chen ◽  
Qi Wei ◽  
Da-Jian Wu
Keyword(s):  
Acoustic Waves ◽  
High Efficiency ◽  
Low Frequency ◽  
Frequency Noise ◽  
Sound Waves ◽  
Broadband Absorption ◽  
Trapped Mode ◽  
Potential Applications ◽  
Simulation And Experiment ◽  
Interest In Research

Abstract Broadband absorption of low-frequency sound waves via a deep subwavelength structure is of great and ongoing interest in research and engineering. Here, we numerically and experimentally present a design of a broadband low-frequency absorber based on an acoustic metaporous composite (AMC). The AMC absorber is constructed by embedding a single metamaterial resonator into a porous layer. The finite element simulations show that a high absorption (absorptance A > 0.8) can be achieved within a broad frequency range (from 290 Hz to 1074 Hz), while the thickness of AMC is 1/13 of the corresponding wavelength at 290 Hz. The broadband and high-efficiency performances of the absorber are attributed to the coupling between the two resonant absorptions and the trapped mode. A good agreement between the numerical simulation and experiment is obtained. Moreover, the high broadband absorption can be maintained under random incident acoustic waves. The proposed absorber provides potential applications in low-frequency noise reduction especially when limited space is demanded.

Study on low frequency sound insulation characteristic of thin acoustic black hole

2021 ◽  
pp. 2150198
Author(s):  
Xiao Lian ◽  
Shengsheng Wang ◽  
Maolin Liu ◽  
Songhui Nie ◽  
Jinfeng Peng ◽  
...  
Keyword(s):  
Black Hole ◽  
Acoustic Waves ◽  
Transmission Loss ◽  
Low Frequency ◽  
Sound Insulation ◽  
Focusing Effect ◽  
Frequency Sound ◽  
Leading Role ◽  
Potential Applications ◽  
Energy Focusing

We use numerical and experimental methods to investigate the low frequency sound insulation characteristic of designed thin acoustic black hole (ABH). The numerical results show that the sound energy focusing effect plays a leading role in low frequency sound insulation of designed ABH, and the reflection at the edge of ABH is the main reason of sound insulation in medium and high frequencies. Experimental results display that the Sound Transmission Loss (STL) of the designed ABH is higher than 30 dB below 700 Hz, which shows that the isolated acoustic waves are more than 95%. The low frequency sound insulation performance of proposed ABHs is much better than the traditional acoustic materials, which has great potential applications for low frequency sound insulation.

Underwater metastructure with broadband sound absorption capability in low-frequency range above 20 Hz

2020 ◽  
pp. 2150039
Author(s):  
Ruihao Zhang ◽  
Yifan Song ◽  
Hong Hou ◽  
Nansha Gao
Keyword(s):  
Absorption Coefficient ◽  
Acoustic Waves ◽  
Sound Absorption ◽  
Low Frequency ◽  
Sound Absorption Coefficient ◽  
Rubber Matrix ◽  
Conical Cavity ◽  
Propagation Law ◽  
Potential Applications ◽  
Metal Disk

We present an underwater metastructure with excellent sound absorption effect below 50 Hz. The periodic metastructure unit consists of a conical cavity, rubber matrix, and two metal disks. FEM results show that, in the range of 20–300 Hz, the proposed metastructure demonstrates the excellent sound absorption within 279 Hz bandwidth when the reference absorption coefficient is considered to be 0.5. Displacement vibration diagrams illustrate the addition of two layers of metal disks break the propagation law of acoustic wave in rubber matrix. An anti-phase motion of the rubber matrix emerges due to the presence of the metal disks, then consumes the energy of incident acoustic waves. The geometric parameters of lattice constant [Formula: see text], the thickness [Formula: see text], and the height [Formula: see text] of the upper metal disk are positively correlated with the sound absorption coefficient, while the upper radius [Formula: see text] and the height [Formula: see text] of the conical cavity are negatively correlated with the sound absorption coefficient. The novel design presented in this study could have the potential applications in the realization of an acoustic underwater anechoic layer.

Manipulation of negative-index collimation beam using band-gap guidance

2018 ◽  
Vol 82 (1) ◽  
pp. 10401
Author(s):  
Fengfu Shen ◽  
Ge Zhu ◽  
Qing Shi ◽  
Zengtao Lv
Keyword(s):  
Integrated Circuits ◽  
Band Gap ◽  
Acoustic Waves ◽  
Resonant Mode ◽  
Negative Index ◽  
First Order ◽  
Directional Emission ◽  
Source Distance ◽  
Potential Applications ◽  
Sonic Crystal

We manipulate the source distance, emission position and number of negative-index collimation beam in a two-dimensional hybrid sonic crystal by using band-gap waveguide to control the flow of acoustic waves from a point source. The desired beam manipulations can be achieved at many different frequencies by suitably selecting the first order resonant mode of two crystal components and the waveguide structures. These results have potential applications in acoustic mutifunctional directional emission and acoustic integrated circuits. The proposed approach is also applicable for the similar manipulations of other types of acoustic collimation beams.

scholarly journals Locally Resonant Phononic Crystals at Low frequencies Based on Porous SiC Multilayer

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ahmed Mehaney ◽  
Ashour M. Ahmed
Keyword(s):  
Band Gap ◽  
Frequency Band ◽  
Acoustic Waves ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Band Gaps ◽  
Resonance Phenomenon ◽  
Porous Sic ◽  
Phononic Band Gaps ◽  
Sound Suppression

Abstract In this work, a one-dimensional porous silicon carbide phononic crystal (1D-PSiC PnC) sandwiched between two rubber layers is introduced to obtain low frequency band gaps for the audible frequencies. The novelty of the proposed multilayer 1D-PnCs arises from the coupling between the soft rubber, unique mechanical properties of porous SiC materials and the local resonance phenomenon. The proposed structure could be considered as a 1D acoustic Metamaterial with a size smaller than the relevant 1D-PnC structures for the same frequencies. To the best of our knowledge, it is the first time to use PSiC materials in a 1D PnC structure for the problem of low frequency phononic band gaps. Also, the porosities and thicknesses of the PSiC layers were chosen to obtain the fundamental band gaps within the bandwidth of the acoustic transducers and sound suppression devices. The transmission spectrum of acoustic waves is calculated by using the transfer matrix method (TMM). The results revealed that surprising low band gaps appeared in the transmission spectra of the 1D-PSiC PnC at the audible range, which are lower than the expected ones by Bragg’s scattering theory. The frequency at the center of the first band gap was at the value 7957 Hz, which is 118 times smaller than the relevant frequency of other 1D structures with the same thickness. A comparison between the phononic band gaps of binary and ternary 1D-PSiC PnC structures sandwiched between two rubber layers at the micro-scale was performed and discussed. Also, the band gap frequency is controlled by varying the layers porosity, number and the thickness of each layer. The simulated results are promising in many applications such as low frequency band gaps, sound suppression devices, switches and filters.

Frequency response characteristics of finite periodic chiral structures with three ligaments

2019 ◽  
Vol 233 (12) ◽  
pp. 4623-4634 ◽  
Author(s):  
Xunwen Su ◽  
Dongmei Zhu ◽  
Chao Zheng ◽  
Mileta M Tomovic
Keyword(s):  
Frequency Response ◽  
Band Gap ◽  
Low Frequency ◽  
Harmonic Excitation ◽  
Chiral Structure ◽  
Response Characteristics ◽  
Chiral Structures ◽  
Frequency Response Characteristics ◽  
Gap Width ◽  
Attenuation Characteristics

The frequency response model of the chiral structure with three ligaments is built using finite element method. By the unit harmonic excitation force, the displacement responses of the point of applying unit force and a point far away from that point are obtained. The effects of different geometric parameters and the filler in the nodes on the response characteristics under medium–low frequency are studied. The results indicate that the node radius, ligament thickness, and ligament length have significant effects on the frequency response characteristics of the chiral structure with three ligaments. The starting frequency and the gap width of the frequency gap can be adjusted by changing the node radius of the limited periodic chiral structure. The filler in the nodes can change the starting frequency and width of the frequency gap. Hence, the narrow band gap under low frequency is obtained. When the frequency of the vibration is in the band gap, the chiral structure with the three ligaments has good attenuation characteristics. The results of this paper can provide the references for the design of chiral structure in the aeronautic and aerospace engineering.

Search of Phononic Crystal Band-Gap about the Array of 2D Square Tube with Slits

2014 ◽  
Vol 536-537 ◽  
pp. 1481-1485
Author(s):  
Long Gen Li ◽  
Yong Gang Chen
Keyword(s):  
Band Gap ◽  
Acoustic Waves ◽  
Structural Parameters ◽  
Phononic Crystal ◽  
Low Frequency ◽  
Propagation Characteristic ◽  
Steel Tube ◽  
The Finite Element Method ◽  
Transmission Coefficients ◽  
Square Array

A band structure composed of a square array of parallel steel tube with narrow slits is presented.The propagation characteristic of acoustic waves in this structure is investigated theoretically by the finite element method. In particular the acoustic-solid coupling is taken into account for accurate results. The transmission coefficients of the band system with different angles of the square tubes and slits width are calculated. A large continuous band gap at a low frequency range in a compound structure is obtained due to the interaction of peaks and gaps fordifferent Structural parameters.

Experimental Study of the Transmission Spectrum of a Sonic/Ultrasonic Acoustic Metamaterial

2016 ◽  
Author(s):  
Yanbo He ◽  
Jeffrey S. Vipperman
Keyword(s):  
Band Gap ◽  
Frequency Band ◽  
Transmission Spectrum ◽  
Physical Phenomenon ◽  
Experimental Studies ◽  
Low Frequency ◽  
Acoustic Metamaterials ◽  
Acoustic Metamaterial ◽  
Potential Applications ◽  
Lower Frequency Band

Acoustic metamaterials have received much attention recently. In the past decades, countless structures have been studied for their novel physical phenomenon or potential applications. The goals of many of the works were to explore ways to enlarge the band gap, lower the band gap frequency, and/or generate greater attenuation of vibration. However, most of the work was limited to simulation, with experimental studies rarer. In this work, we would like to experimentally present the transmission spectrum of an acoustic metamaterial with a proposed structure called the coated double hybrid lattice (CDHL) [1]. The CDHL has both crystalline structure and local resonators, which provide high-frequency and low-frequency band gaps, respectively. A structure was fabricated and tested to experimentally determine the transmission spectrum. Both, a higher frequency band gap and a lower frequency band gap, were obtained. Vibration is clearly attenuated in the frequency range of 70–90 kHz. This is due to the Bragg scattering effect. At the same time, around the frequency of 4.8kHz, another band gap is observed which is attributed to local resonance. It turns out that our experimental results coincide with our previous simulation quite well.

Efficient Prediction of Structural and Electronic Properties of Hybrid 2D Materials Using DFT and Machine Learning

2018 ◽  
Author(s):  
Sherif Tawfik ◽  
Olexandr Isayev ◽  
Catherine Stampfl ◽  
Joseph Shapter ◽  
David Winkler ◽  
...  
Keyword(s):  
Machine Learning ◽  
Band Gap ◽  
Density Functional ◽  
2D Materials ◽  
Van Der Waals ◽  
Building Blocks ◽  
Machine Learning Techniques ◽  
Interlayer Distance ◽  
Computational Screening ◽  
Wide Range

Materials constructed from different van der Waals two-dimensional (2D) heterostructures offer a wide range of benefits, but these systems have been little studied because of their experimental and computational complextiy, and because of the very large number of possible combinations of 2D building blocks. The simulation of the interface between two different 2D materials is computationally challenging due to the lattice mismatch problem, which sometimes necessitates the creation of very large simulation cells for performing density-functional theory (DFT) calculations. Here we use a combination of DFT, linear regression and machine learning techniques in order to rapidly determine the interlayer distance between two different 2D heterostructures that are stacked in a bilayer heterostructure, as well as the band gap of the bilayer. Our work provides an excellent proof of concept by quickly and accurately predicting a structural property (the interlayer distance) and an electronic property (the band gap) for a large number of hybrid 2D materials. This work paves the way for rapid computational screening of the vast parameter space of van der Waals heterostructures to identify new hybrid materials with useful and interesting properties.

Sign in / Sign up

Export Citation Format

Share Document