scholarly journals A Review of Tunable Acoustic Metamaterials

2018 ◽  
Vol 8 (9) ◽  
pp. 1480 ◽  
Author(s):  
Shuang Chen ◽  
Yuancheng Fan ◽  
Quanhong Fu ◽  
Hongjing Wu ◽  
Yabin Jin ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Acoustic Impedance ◽  
Acoustic Waves ◽  
Recent Progress ◽  
The Novel ◽  
Acoustic Metamaterials ◽  
Practical Application ◽  
Acoustic Metamaterial ◽  
Modulation Techniques ◽  
Narrow Frequency Band

Acoustic metamaterial science is an emerging field at the frontier of modern acoustics. It provides a prominent platform for acoustic wave control in subwavelength-sized metadevices or metasystems. However, most of the metamaterials can only work in a narrow frequency band once fabricated, which limits the practical application of acoustic metamaterials. This paper highlights some recent progress in tunable acoustic metamaterials based on various modulation techniques. Acoustic metamaterials have been designed to control the attenuation of acoustic waves, invisibility cloaking, and acoustic wavefront engineering, such as focusing via manipulating the acoustic impedance of metamaterials. The reviewed techniques are promising in extending the novel acoustics response into wider frequency bands, in that tunable acoustic metamaterials may be exploited for unusual applications compared to conventional acoustic devices.

scholarly journals AKUSTIČKI METAMATERIJALI: PREGLED VIBRACIONIH KARAKTERISTIKA

2018 ◽  
pp. 103
Author(s):  
Livija Cveticanin ◽  
Dragan Cveticanin
Keyword(s):  
Acoustic Wave ◽  
Mathematical Models ◽  
Basic Principle ◽  
Acoustic Waves ◽  
Solid Material ◽  
Vibration Absorbers ◽  
Acoustic Metamaterials ◽  
Acoustic Metamaterial ◽  
Negative Effective Mass ◽  
Artificial Materials

In the paper the theoretical consideration of the acoustic metamaterials is given. Metamaterials, which are usually composite, are artificial materials whose properties differ from those observed in nature or in the constituent materials. Metamaterials which are suitable for acoustic wave absorption are presented. Acoustic absorber is a beam made of solid material connected with spring-mass subunits. The purpose of the subunits is to give a band gap where some frequencies of acoustic wave are stopped. Mathematical models for various types of connection of subunits in the metamaterial and absorber are discussed. Based on the analogy between electromagnetic and acoustic waves the concept of negative effective mass is introduced as a basic principle for modeling. Acoustic metamaterial beams based on one, two or multi-frequency vibration absorbers are discussed. Depending on connection of absorbers in the beam, the structure may absorb wave in one-direction (for example the longitudinal one) or waves in two directions (transversal and longitudinal). In the paper an overview of mathematical models and suggestions for further investigation are given.

Design and Fabrication of a High Frequency Thin Film Resonator Using Low Acoustic Impedance Reflective Layer

2003 ◽  
Author(s):  
Chung-Hsien Lin ◽  
Hong-Ren Chen ◽  
Chen-Hsun Du ◽  
Weileun Fang
Keyword(s):  
Thin Film ◽  
Mobile Communication ◽  
Acoustic Impedance ◽  
Piezoelectric Layer ◽  
Acoustic Waves ◽  
High Frequency ◽  
The Novel ◽  
Novel Device ◽  
Reflective Layer ◽  
Air Interface

A high frequency thin film resonator using single reflective layer is presented. The reflective layer is chosen to have a low acoustic impedance to reflect acoustic waves, which is generated by the piezoelectric layer above it. With an air interface serves as a free boundary at the other end of piezoelectric layer, a high frequency resonator can be formed. Since the fabrication process included no bulk etching and multi-layer, a high manufacturability can be achieved. Moreover, the novel device and its applications can be designed to be suit many mobile communication applications.

Modulational instability and rogue waves in one-dimensional nonlinear acoustic metamaterials: case of diatomic model

2021 ◽  
Author(s):  
Joseph Mora ◽  
Justin Mibaile ◽  
Vroumsia David ◽  
Sylvere Azakine ◽  
Gambo Betchewe
Keyword(s):  
Integrable System ◽  
Taylor Series ◽  
Acoustic Waves ◽  
Perturbation Methods ◽  
Modulational Instability ◽  
Rogue Waves ◽  
Acoustic Metamaterials ◽  
One Dimensional ◽  
Acoustic Metamaterial ◽  
Nonlinear Acoustic

Abstract In this paper, by means of the expanded Taylor series and Lindstedt-Poincar ́e perturbation methods, the coupled nonlinear Schrödinger equations (CNLSE) modeling the propagation of acoustic waves in acoustic metamaterial is obtained. Using these equations, the Modulational Instability (MI) phenomenon is observed in disturbance mode. Manakov integrable system is derived with suitable parameters and we shown that the Rogue Waves (RWs) can propagate diatomic acoustic metamaterials.

Bloch-Theory-Based Analysis of Damped Phononic Materials

2011 ◽  
Author(s):  
Michael J. Frazier ◽  
Mahmoud I. Hussein
Keyword(s):  
Band Structure ◽  
Wave Attenuation ◽  
Effective Properties ◽  
The Novel ◽  
Acoustic Metamaterials ◽  
Mass Model ◽  
Acoustic Metamaterial ◽  
Optical Branch ◽  
Lumped Parameter ◽  
Impact Vibration

In this paper, we combine Bloch theory with familiar techniques of structural dynamics to study the effects of energy dissipation (i.e., damping) in an acoustic metamaterial. The formulation we present has the novel feature of incorporating a temporal component to wave attenuation in addition to the standard spatial component. The frequency band structure reflects the metamaterial response to the damping intensity. In the context of a lumped parameter nested mass model, increasing the magnitude of damping is shown to cause the band structure to descend the frequency range and reveal an intriguing phenomenon: branch overtaking. This effect occurs as dissipation causes the optical branch to descend below the acoustical branch. The resulting decrease in the width of the band gap would impact vibration minimization and isolation. We also examine the effective properties of the metamaterial, specifically, the effective mass and effective stiffness, and the conditions for these quantities to become negative. Finally, the aforementioned material results are shown to be related to their finite counterpart. For ease of exposition, we consider a special form of Rayleigh damping in which the damping is proportional to the stiffness. The intrinsic presence of dissipation in acoustic metamaterials and the limited scientific literature addressing damped wave propagation in periodic media in general motivates our present study.

scholarly journals Formation of a Complex Topologies of SAW-Based Inertial Sensors by Laser Thin Film Local Evaporation

Micromachines ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 10
Author(s):  
Alexander Kukaev ◽  
Dmitry Lukyanov ◽  
Denis Mikhailenko ◽  
Daniil Safronov ◽  
Sergey Shevchenko ◽  
...  
Keyword(s):  
Thin Film ◽  
Acoustic Wave ◽  
Surface Acoustic Wave ◽  
Acoustic Waves ◽  
Inertial Sensors ◽  
Surface Acoustic Waves ◽  
Sensing Element ◽  
Small Series ◽  
Evaporation Technique ◽  
Photolithography Process

Originally, sensors based on surface acoustic waves are fabricated using photolithography, which becomes extremely expensive when a small series or even single elements are needed for the research. A laser thin film local evaporation technique is proposed to substitute the photolithography process in the production of surface acoustic wave based inertial sensors prototypes. To estimate its potential a prototype of a surface acoustic wave gyroscope sensing element was fabricated and tested. Its was shown that the frequency mismatch is no more than 1%, but dispersion of the wave on small inertial masses leads to a spurious parasitic signal on receiving electrodes. Possible ways of its neglecting is discussed.

Linear and Nonlinear Analysis of Additively Manufactured Material With Different Porosity Induced by Varying Material Printing Speed Using Guided Acoustic Waves

2021 ◽  
Author(s):  
SeHyuk Park ◽  
Hamad Alnuaimi ◽  
Anna Hayes ◽  
Madison Sitkiewicz ◽  
Umar Amjad ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Nonlinear Analysis ◽  
Lead Zirconate Titanate ◽  
Acoustic Waves ◽  
Scanning Speed ◽  
Lead Zirconate ◽  
Nonlinear Ultrasonic ◽  
Scan Speed ◽  
Linear And Nonlinear ◽  
Characterization Of Materials

Abstract Guided acoustic wave based techniques have been found to be very effective for damage detection, and both quantitative and qualitative characterization of materials. In this research, guided acoustic wave techniques are used for porosity evaluation of additively manufactured materials. A metal 3D printer, Concept Laser Mlab 200 R Cusing™, is used to manufacture 316L additively manufactured (AM) stainless steel specimens. Two levels of porosity are investigated in this study, which was controlled by a suitable combination of scan speed and laser power. The sample with lower level of porosity is obtained with a low scanning speed. Lead Zirconate Titanate (PZT) transducers are used to generate guided acoustic waves. The signal is excited and propagated through the specimens in a single sided transmission mode setup. Signal processing of the recorded signals for damage analysis involves both linear and nonlinear analyses. Linear ultrasonic parameters such as the time-of-flight and magnitude of the propagating waves are recorded. The nonlinear ultrasonic parameter, the Sideband Peak Count Index (SPC-I) is obtained by a newly developed nonlinear analysis technique. Results obtained for both specimens are analyzed and compared using both linear and nonlinear ultrasonic techniques. Finally, the effectiveness of SPC-I technique in monitoring porosity levels in AM specimens is discussed.

scholarly journals Breathable Materials for Triboelectric Effect-Based Wearable Electronics

2018 ◽  
Vol 8 (12) ◽  
pp. 2485 ◽  
Author(s):  
Congju Li ◽  
Ran Cao ◽  
Xiuling Zhang
Keyword(s):  
Recent Progress ◽  
Dielectric Materials ◽  
Wearable Devices ◽  
Wearable Electronics ◽  
Practical Application ◽  
Metal Mesh ◽  
Frictional Materials ◽  
Nanofiber Membranes ◽  
Materials Used ◽  
Triboelectric Effect

Wearable electronics are believed to be the future of the next-generation electric devices. However, the comfort of current wearable devices is greatly limited due to the use of airtight materials, which may even lead to inflammation of the skin. Therefore, breathable, skin-friendly materials, are highly desired for wearable devices. Here, the recent progress of the breathable materials used to fabricate skin-friendly electronics is reviewed by taking triboelectric effect-based wearable electronics as a typical example. Fibers, yarns, textiles, and nanofiber membranes are the most popular dielectric materials that serve as frictional materials. Metal mesh, silver yarn, and conductive networks made up of nanomaterial are preferred as air-permissive electrodes. The breathable materials for skin-friendly wearable electronics summarized in this review provide valuable references for future fabrication of humanized wearable devices and hold great significance for the practical application of wearable devices.

scholarly journals Modelling damped acoustic waves by a dissipation-preserving conformal symplectic method

2017 ◽  
Vol 473 (2199) ◽  
pp. 20160798 ◽  
Author(s):  
Wenjun Cai ◽  
Huai Zhang ◽  
Yushun Wang
Keyword(s):  
Wave Equation ◽  
Acoustic Wave ◽  
Acoustic Waves ◽  
Conservation Law ◽  
Heterogeneous Media ◽  
Numerical Dispersion ◽  
Discrete Version ◽  
Symplectic Method ◽  
Ode System ◽  
Strang Splitting

We propose a novel stable and efficient dissipation-preserving method for acoustic wave propagations in attenuating media with both correct phase and amplitude. Through introducing the conformal multi-symplectic structure, the intrinsic dissipation law and the conformal symplectic conservation law are revealed for the damped acoustic wave equation. The proposed algorithm is exactly designed to preserve a discrete version of the conformal symplectic conservation law. More specifically, two subsystems in conjunction with the original damped wave equation are derived. One is actually the conservative Hamiltonian wave equation and the other is a dissipative linear ordinary differential equation (ODE) system. Standard symplectic method is devoted to the conservative system, whereas the analytical solution is obtained for the ODE system. An explicit conformal symplectic scheme is constructed by concatenating these two parts of solutions by the Strang splitting technique. Stability analysis and convergence tests are given thereafter. A benchmark model in homogeneous media is presented to demonstrate the effectiveness and advantage of our method in suppressing numerical dispersion and preserving the energy dissipation. Further numerical tests show that our proposed method can efficiently capture the dissipation in heterogeneous media.

scholarly journals Complex interactions in legume/cereal intercropping system: role of root exudates in root-to-root communication

2017 ◽  
Author(s):  
Yinshan Jiao ◽  
Entao Wang ◽  
Wenfeng Chen ◽  
Donald L. Smith
Keyword(s):  
Nitrogen Fixation ◽  
Root Exudates ◽  
Faba Bean ◽  
The Novel ◽  
Practical Application ◽  
Corn Root ◽  
Complex Interactions ◽  
Root Interactions ◽  
Ecological Principles

Dear Editor,Legume/cereal intercropping systems have been regarded as the practical application of basic ecological principles such as diversity, competition and facilitation. In a recent PNAS paper, Li et al. (1) describe the novel finding that maize exudates promote faba bean nodulation and nitrogen fixation by upregulating genes involved in (iso)flavonoids synthesis (chalcone–flavanone isomerase) within faba bean, resulting in production of more genistein, a legume-to-rhizobia signal during establishment of the faba bean N2–fixing symbiosis. Although we salute the authors’ methodological efforts, there is another mechanism that could be responsible for the effect of corn root exudates on faba been nitrogen fixation observed in this article (1). The authors may misunderstand their data and the signalling role of maize exudates, thus got a defective model for the root interactions between faba bean and maize.

scholarly journals Analysis of Propagation and Distribution Characteristics of Leakage Acoustic Waves in Water Supply Pipelines

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5450
Author(s):  
Yunfei Li ◽  
Yang Zhou ◽  
Ming Fu ◽  
Fan Zhou ◽  
Zhaozhao Chi ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Water Supply ◽  
Acoustic Waves ◽  
Simulation Analysis ◽  
Acoustic Signals ◽  
Detection Methods ◽  
Acoustic Analogy ◽  
Acoustic Wave Propagation ◽  
Source Characteristics ◽  
Water Supply Pipeline

Leakage detection methods based on the analysis of leakage acoustic signals provide an effective technical approach for detecting small leaks in water supply pipelines. From a technical perspective, the study of the propagation characteristics of acoustic waves generated by the leakage in the water supply pipeline is necessary for detecting the leak location on the basis of acoustic signals. In this study, a 3D transient leakage acoustic wave propagation equation was derived by combining the principles of fluid dynamics and Lighthill acoustic analogy theory. The propagation of the leakage-induced noise in water supply pipeline was modelled theoretically. We simulated the propagation of a leakage acoustic wave under different conditions for different target scenarios encountered in actual pipeline inspections. Specifically, we analysed the effect of different factors, such as the pipe size and acoustic source characteristics, on acoustic propagation. Finally, the simulated experiments were practically performed using a self-designed simulated water supply pipeline and self-developed spherical water supply pipeline detector to validate the simulation analysis. The results of this study provide a theoretical guidance and basis for the analysis of characteristics of leakage acoustic wave signals and the recognition of leakage conditions in water supply pipelines.

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