Seismic Waveguide of Metamaterials

Modern Physics Letters B (Impact Factor: 0.75). 02/2012; 26(17). DOI: 10.1142/S0217984912501059
Source: arXiv


We have developed a new method of an earthquake-resistant design to support
conventional aseismic designs using acoustic metamaterials. We suggest a simple
and practical method to reduce the amplitude of a seismic wave exponentially.
Our device is an attenuator of a seismic wave. Constructing a cylindrical
shell-type waveguide that creates a stop-band for the seismic wave, we convert
the wave into an evanescent wave for some frequency range without touching the
building we want to protect.

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Available from: Mukunda Das, May 21, 2015
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    • "Finally, we would like to mention in passing that our study may find important applications in seismic metamaterials (cf. [10] [34] [35] [45]) to construct feasible devices for protecting key structures from the catastrophic destruction of natural earthquake waves or terrorist attacks (e.g., nuclear blast). For instance, the elastic invisibility cloak could be of great significance in safeguarding nuclear power plants, electric pylons, oil refineries , nuclear reactors and old or fragile monuments as well as the important components within them. "
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    ABSTRACT: In this work, we develop a general mathematical framework on regularized approximate cloaking of elastic waves governed by the Lam\'e system via the approach of transformation elastodynamics. Our study is rather comprehensive. We first provide a rigorous justification of the transformation elastodynamics. Based on the blow-up-a-point construction, elastic material tensors for a perfect cloak are derived and shown to possess singularities. In order to avoid the singular structure, we propose to regularize the blow-up-a-point construction to be the blow-up-a-small-region construction. However, it is shown that without incorporating a suitable lossy layer, the regularized construction would fail due to resonant inclusions. In order to defeat the failure of the lossless construction, a properly designed lossy layer is introduced into the regularized cloaking construction . We derive sharp asymptotic estimates in assessing the cloaking performance. The proposed cloaking scheme is capable of nearly cloaking an arbitrary content with a high accuracy.
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    ABSTRACT: We developed a new method of earthquakeproof engineering to create an artificial seismic shadow zone using acoustic metamaterials. By designing huge empty boxes with a few side-holes corresponding to the resonance frequencies of seismic waves and burying them around the buildings that we want to protect, the velocity of the seismic wave becomes imaginary. The meta-barrier composed of many meta-boxes attenuates the seismic waves, which reduces the amplitude of the wave exponentially by dissipating the seismic energy. This is a mechanical method of converting the seismic energy into sound and heat. We estimated the sound level generated from a seismic wave. This method of area protection differs from the point protection of conventional seismic design, including the traditional cloaking method. The meta-barrier creates a seismic shadow zone, protecting all the buildings within the zone. The seismic shadow zone is tested by computer simulation and compared with a normal barrier.
    Modern Physics Letters B 10/2012; 27(20). DOI:10.1142/S0217984913501406 · 0.75 Impact Factor
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    ABSTRACT: There are two methods for earthquake engineering as an application of acoustic metamaterials. One is the traditional cloaking method that makes the seismic wave deflect the building to be protected. The other is the artificial shadow zone method that makes the seismic wave disappear by attenuation. We will explain the fundamental principles of the two methods and compare the advantages and disadvantages of both.
    2013 7th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics (METAMATERIALS 2013); 09/2013
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