scholarly journals Metamaterial with anisotropic mass density for full mode-converting transmission of elastic waves in the ultralow frequency range

AIP Advances ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 125205
Author(s):  
Xiongwei Yang ◽  
Yijun Chai ◽  
Yueming Li
Keyword(s):  
Elastic Waves ◽  
Mass Density ◽  
Frequency Range ◽  
Ultralow Frequency ◽  
Anisotropic Mass Density

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.

Double membrane sensors for liquid viscosity and mass density facilitating measurements in a large frequency range

2010 ◽  
Author(s):  
Martin Heinisch ◽  
Thomas Voglhuber-Brunnmaier ◽  
Alexander Niedermayer ◽  
Bernhard Jakoby ◽  
Erwin K Reichel
Keyword(s):  
Mass Density ◽  
Liquid Viscosity ◽  
Frequency Range ◽  
Double Membrane ◽  
Large Frequency

Instrument for measuring phase and amplitude of harmonics in the ultralow-frequency range

1976 ◽  
Vol 19 (11) ◽  
pp. 1650-1654
Author(s):  
V. D. Stashuk ◽  
V. A. Panchul
Keyword(s):  
Frequency Range ◽  
Ultralow Frequency

Diffraction of elastic waves from object in layer with slightly corrugated surface

2017 ◽  
Vol 23 (9) ◽  
pp. 1249-1262 ◽  
Author(s):  
Khaled M Elmorabie ◽  
Rania R Yahya
Keyword(s):  
Elastic Waves ◽  
Perturbation Technique ◽  
Scattering Problem ◽  
Integral Equation Method ◽  
Boundary Integral ◽  
Harmonic Load ◽  
Frequency Range ◽  
Corrugated Surfaces ◽  
Geometrical Shapes ◽  
Diffraction Of Elastic Waves

This work is concerned with the influence of corrugated surfaces on waves diffracted from an object in an elastic layer. A boundary value problem is formulated to simulate an anti-plane problem for a harmonic load acting on the upper surface of the layer. By using the boundary integral equation method and the perturbation technique, the considered problem is reduced to a pair of integral equations. By constructing the Green’s function, the scattering problem in a one-mode frequency range is solved. To check the validity of the proposed technique, several numerical examples for different geometrical shapes of the corrugated bottom are presented.

Controllable acoustic media having anisotropic mass density and tunable speed of sound

2012 ◽  
Vol 101 (6) ◽  
pp. 061916 ◽  
Author(s):  
Mark J. Seitel ◽  
Jerry W. Shan ◽  
Stephen D. Tse
Keyword(s):  
Speed Of Sound ◽  
Mass Density ◽  
Acoustic Media ◽  
Anisotropic Mass Density

Elastic Waves in Pipe Resting on Two-Parameter Foundation

2010 ◽  
Vol 163-167 ◽  
pp. 2857-2861 ◽  
Author(s):  
Zhi Rong Lin ◽  
Akira Kasai
Keyword(s):  
Wave Propagation ◽  
Elastic Waves ◽  
Low Frequency ◽  
Curvilinear Coordinates ◽  
Complex Field ◽  
Frequency Range ◽  
Wave Propagation Problem ◽  
Propagating Waves ◽  
Foundation Parameter ◽  
Two Parameter

A method based on Hamiltonian system in complex field is presented in curvilinear coordinates to study elastic waves in pipes of various shapes on two-parameter foundation. The method and its computer program are verified and applied to analyze the axial wave propagation problem of elliptical pipe embedded in foundation. Numerical results show the dispersion changes of varying degree in the presence of foundation and reveal significant influences of the second foundation parameter especially in the low frequency range. The promising and effective way of controlling propagating waves by adjusting the shear ability of foundation is also indicated in the results.

An identification problem related to the Biot system

2014 ◽  
Vol 0 (0) ◽  
Author(s):  
Viatcheslav I. Priimenko ◽  
Mikhail P. Vishnevskii
Keyword(s):  
Elastic Waves ◽  
Existence And Uniqueness ◽  
Direct Problem ◽  
Low Frequency ◽  
Identification Problem ◽  
Scalar Function ◽  
Uniqueness Result ◽  
Frequency Range ◽  
Biot Equations ◽  
Propagation Of Elastic Waves

Abstract.In this paper, we study the propagation of elastic waves in porous media governed by the Biot equations in the low frequency range. We prove the existence and uniqueness result both for the direct problem and the inverse one, which consists in identifying the unknown scalar function

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