scholarly journals Inverse Doppler effect of acoustic metamaterial with negative mass density

2017 ◽  
Vol 66 (2) ◽  
pp. 024301
Author(s):  
Liu Song ◽  
Luo Chun-Rong ◽  
Zhai Shi-Long ◽  
Chen Huai-Jun ◽  
Zhao Xiao-Peng
Keyword(s):  
Doppler Effect ◽  
Mass Density ◽  
Negative Mass ◽  
Acoustic Metamaterial

An Acoustic Metamaterial Bending Waveguide Design Using Transformation Acoustics

2011 ◽  
Author(s):  
Liang-Yu Wu ◽  
Tzeh-Yi Chiang ◽  
Mei-Ling Wu ◽  
Lien-Wen Chen
Keyword(s):  
Layered Structure ◽  
Material Properties ◽  
Mass Density ◽  
Homogeneous Material ◽  
Two Dimensional ◽  
Negative Mass ◽  
Acoustic Metamaterial ◽  
Transformation Medium ◽  
Waveguide Design ◽  
Transformation Acoustics

An acoustic bending waveguide is designed by transformation acoustics. A two-dimensional square area with anisotropic and homogeneous material properties is transformed into a fan-shaped area with anisotropic and inhomogeneous material properties to rotate the direction of beam propagation. The transformation medium can be realized by alternating layered structure consisting of water and fluid with negative mass density. We propose that an acoustic metamaterial composed of three layers in water background can be designed to replace negative mass density fluid and achieve the acoustic bending waveguide.

Acoustic metamaterial with negative mass density in water

2015 ◽  
Vol 118 (9) ◽  
pp. 094901 ◽  
Author(s):  
Huaijun Chen ◽  
Shilong Zhai ◽  
Changlin Ding ◽  
Chunrong Luo ◽  
Xiaopeng Zhao
Keyword(s):  
Mass Density ◽  
Negative Mass ◽  
Acoustic Metamaterial

Anisotropic Band Gap in a 2D Acoustic Metamaterial

2009 ◽  
Author(s):  
H. H. Huang ◽  
C. T. Sun
Keyword(s):  
Band Gap ◽  
Dynamic Behavior ◽  
Continuum Model ◽  
Wave Motion ◽  
Mass Density ◽  
Internal Mass ◽  
Negative Mass ◽  
Elastic Continuum ◽  
Acoustic Metamaterial ◽  
Band Gap Structure

A two-dimensional (2D) metamaterial possessing an effective anisotropic mass is investigated. This metamaterial is a composite material in the form of an internal mass connected in two directions to the host medium. A 2D mass-in-mass lattice model is used to characterize the dynamic behavior of the metamaterial. If modeled as an effective spring-mass lattice system, the metamaterial may possess a frequency-dependent effective mass. Moreover, if an equivalent homogenous elastic continuum is used to represent the metamaterial, an anisotropic mass density may result and may assume negative values for wave frequencies that are near the local resonance frequency of the internal mass. In fact, it was found that negative mass density occurs in the band-gap of the metamaterial. Unusual wave motion arises from the anisotropic band gap structure. In the present study, wave propagation in the representative continuum model for the metamaterial is studied in order to understand the unusual features of the dynamic behavior of the metamaterial.

An elastic metamaterial with simultaneously negative mass density and bulk modulus

2011 ◽  
Vol 98 (25) ◽  
pp. 251907 ◽  
Author(s):  
X. N. Liu ◽  
G. K. Hu ◽  
G. L. Huang ◽  
C. T. Sun
Keyword(s):  
Bulk Modulus ◽  
Mass Density ◽  
Negative Mass

Novel negative mass density resonant metamaterial unit cell

2015 ◽  
Vol 379 (1-2) ◽  
pp. 33-36 ◽  
Author(s):  
Norbert Cselyuszka ◽  
Milan Sečujski ◽  
Vesna Crnojević-Bengin
Keyword(s):  
Mass Density ◽  
Unit Cell ◽  
Negative Mass

A design of active elastic metamaterials with negative mass density and tunable bulk modulus

2018 ◽  
Vol 230 (3) ◽  
pp. 1003-1008 ◽  
Author(s):  
Sheng Sang ◽  
Anwer Mhannawee ◽  
Ziping Wang
Keyword(s):  
Bulk Modulus ◽  
Mass Density ◽  
Negative Mass ◽  
Elastic Metamaterials

Silicon Pillars as Resonators in an Acoustical Metamaterial

2014 ◽  
Author(s):  
Bernard Bonello ◽  
Rémi Marchal ◽  
Rayisa Moiseyenko ◽  
Yan Pennec ◽  
Bahram Djafari-Rouhani ◽  
...  
Keyword(s):  
Thin Plate ◽  
Lamb Waves ◽  
Mass Density ◽  
Resonant Mode ◽  
Ultrasonic Technique ◽  
Frequency Range ◽  
Negative Mass ◽  
Laser Ultrasonic ◽  
Compressional Mode ◽  
Bending Modes

We have investigated the propagation of Lamb waves in structures made of either an isolated resonant pillar or a set of pillars arranged in a line on a thin plate. The resonators as well as the plate are made of silicon. FEM computations show that two bending modes and one compressional mode are unambiguously identified in the frequency range of interest (0–10 MHz). We used a laser ultrasonic technique to map both the amplitude and the phase of the normal displacements on top of the pillars and at the surface of the sample. When the frequency is tuned to a resonant mode, either compressional or bending, the pillars vibrate 180° out-of-phase with respect to the Lamb waves, resulting in a negative modulus or negative mass density respectively.

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