scholarly journals SEISMIC WAVEGUIDE OF METAMATERIALS

2012 ◽  
Vol 26 (17) ◽  
pp. 1250105 ◽  
Author(s):  
SANG-HOON KIM ◽  
MUKUNDA P. DAS
Keyword(s):  
Cylindrical Shell ◽  
Seismic Wave ◽  
Stop Band ◽  
Seismic Energy ◽  
New Method ◽  
Acoustic Metamaterials ◽  
Frequency Range ◽  
Helmholtz Resonators ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant

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.

CHARACTERIZATION OF ENERGY DISSIPATIVE CUSHIONS MADE OF Ni-Ti SHAPE MEMORY ALLOY

2021 ◽  
Author(s):  
Ahmet Güllü ◽  
Josiah Owusu Danquah ◽  
Savaş Dilibal
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Damping Ratio ◽  
Seismic Energy ◽  
Dissipated Energy ◽  
Residual Drift ◽  
Displacement Capacity ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant ◽  
Metallic Dampers

Abstract Earthquake-resistant design of structures requires dissipating seismic energy by deformations of structural members or additional fuse elements. Owing to its easy-to-produce, plug-and-play, high equivalent damping ratio, and large displacement capacity characteristics, energy dissipative steel cushions were found to be an efficient candidate for this purpose. However, similar to other conventional metallic dampers, residual displacement after a strong shaking is the most notable drawback of the steel cushions. In this work, cushions produced from Ni-Ti shape memory alloy are evaluated numerically by experimentally verified finite element models to assess their impact on the performance of earthquake-resistant structures. Furthermore, a reinforced concrete testing frame is retrofitted with energy dissipative steel and Ni-Ti cushions. Performance of the frames (e.g. dissipated energy by the cushions, hysteretic energy to input energy ratio, maximum drift, and residual drift) with different types of cushions are evaluated by nonlinear response history analyses. The numerical results showed that the steel cushions are effective to reduce peak responses, while Ni-Ti cushions are more favorable to reduce residual drifts and deformations. Hence, a hybrid system, employing the steel and shape memory alloy cushions together, is proposed to reach optimal seismic performance.

scholarly journals ARTIFICIAL SEISMIC SHADOW ZONE BY ACOUSTIC METAMATERIALS

2013 ◽  
Vol 27 (20) ◽  
pp. 1350140 ◽  
Author(s):  
SANG-HOON KIM ◽  
MUKUNDA P. DAS
Keyword(s):  
Seismic Wave ◽  
Seismic Design ◽  
Seismic Waves ◽  
Seismic Energy ◽  
Sound Level ◽  
Acoustic Metamaterials ◽  
Shadow Zone ◽  
Mechanical Method ◽  
Resonance Frequencies ◽  
Proof Engineering

We developed a new method of earthquake-proof 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 artificial seismic shadow zone is tested by computer simulation and compared with a normal barrier.

scholarly journals FUNDAMENTAL STUDY ON EARTHQUAKE RESISTANT DESIGN OF FILL-TYPE DAMS

1983 ◽  
Vol 1983 (339) ◽  
pp. 127-136 ◽  
Author(s):  
Yoshio OHNE ◽  
Hidehiro TATEBE ◽  
Kunitomo NARITA ◽  
Tetsuo OKUMURA
Keyword(s):  
Fundamental Study ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant

A NEURAL NETWORK-WAVELET MODEL FOR GENERATING ARTIFICIAL ACCELEROGRAMS

2004 ◽  
Vol 02 (03) ◽  
pp. 217-235 ◽  
Author(s):  
GENE F. SIRCA ◽  
HOJJAT ADELI
Keyword(s):  
Neural Network ◽  
Geographic Location ◽  
Training Data ◽  
Wavelet Network ◽  
Design Spectrum ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant ◽  
Structural Configurations ◽  
Earthquake Accelerograms ◽  
Artificial Accelerograms

In earthquake-resistant design of structures, for certain structural configurations and conditions, it is necessary to use accelerograms for dynamic analysis. Accelerograms are also needed to simulate the effects of earthquakes on a building structure in the laboratory. A new method of generating artificial earthquake accelerograms is presented through adroit integration of neural networks and wavelets. A counterpropagation (CPN) neural network model is developed for generating artificial accelerograms from any given design spectrum such as the International Building Code (IBC) design spectrum. Using the IBC design spectrum as network input means an accelerogram may be generated for any geographic location regardless of whether earthquake records exist for that particular location or not. In order to improve the efficiency of the model, the CPN network is modified with the addition of the wavelet transform as a data compression tool to create a new CPN-wavelet network. The proposed CPN-wavelet model is trained using 20 sets of accelerograms and tested with additional five sets of accelerograms available from the U.S. Geological Survey. Given the limited set of training data, the result is quite remarkable.

Effect of Double Defects on Transmission Spectra of One-Dimensional Photonic Crystals

2010 ◽  
Vol 663-665 ◽  
pp. 725-728 ◽  
Author(s):  
Yuan Ming Huang ◽  
Qing Lan Ma ◽  
Bao Gai Zhai ◽  
Yun Gao Cai
Keyword(s):  
Photonic Crystals ◽  
Band Gap ◽  
Theoretical Calculations ◽  
Stop Band ◽  
Band Gaps ◽  
Characteristic Matrix ◽  
Frequency Range ◽  
Defect Band ◽  
One Dimensional ◽  
The One

Considered the model of the one-dimensional photonic crystals (1-D PCs) with double defects, the refractive indexes (n2’, n3’ and n2’’, n3’’) of the double defects were 2.0, 4.0 and 4.0, 2.0 respectively. With parameter n2=1.5, n3=2.5, by theoretical calculations with characteristic matrix method, the results shown that for a certain number (14 was taken) of layers of the 1-D PCs, when the double defects abutted, there was a defect band gap in the stop band gap, while when the double defects separated, there occurred two defect band gaps in the stop band gap; besides, with the separation of the two defects, the transmittance of the double defect band gaps decreased gradually. In addition, in this progress, the frequency range of the stop band gap has a little increase from 0.092 to 0.095.

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