Article

Seismic Waveguide of Metamaterials

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

ABSTRACT

We developed a new method of an earthquake-resistant design to support conventional aseismic system using acoustic metamaterials. The device is an attenuator of a seismic wave that reduces the amplitude of the wave exponentially. Constructing a cylindrical shell-type waveguide composed of many Helmholtz resonators that creates a stop-band for the seismic frequency range, we convert the seismic wave into an attenuated one without touching the building that we want to protect. It is a mechanical way to convert the seismic energy into sound and heat.

Download full-text

Full-text

Available from: Mukunda Das, May 21, 2015
  • Source
    • "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. "
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · Oct 2014 · Journal de Mathématiques Pures et Appliqués
  • Source
    [Show abstract] [Hide abstract]
    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.
    Full-text · Article · Oct 2012 · Modern Physics Letters B
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this work the design of a soundproof window which is transparent to the airfiow is presented. The design is based on two wave theories of diffraction and acoustic metamaterials. It consists of a two-dimensional array of strong diffraction-type resonators with many holes centered at each individual resonator. The velocity of the sound is a function of bulk modulus and density of air. The resonator makes the bulk modulus negative and consequently the velocity becomes imaginary at some finite frequency ranges. It was observed that the sound level is reduced by 20 ∼ 30dB in the frequency range from 600 to 2, 300Hz after passing the air holes having a diameter of 5cm.
    No preview · Article · Jan 2013
Show more

We use cookies to give you the best possible experience on ResearchGate. Read our cookies policy to learn more.