Technique for the inversion of backscattered elastic wave data to extract the geometrical parameters of defects with varying shape

1982 ◽  
Vol 41 (6) ◽  
pp. 574-576 ◽  
Author(s):  
F. Cohen‐Tenoudji ◽  
B. R. Tittmann ◽  
G. Quentin
2013 ◽  
Vol 134 (5) ◽  
pp. 3980-3980 ◽  
Author(s):  
Yuanwei Jin ◽  
Yujie Ying ◽  
Deshuang Zhao

Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 201 ◽  
Author(s):  
Seong-Hoon Kee ◽  
Jin-Wook Lee ◽  
Ma. Doreen Candelaria

The main objectives of this study are to develop a non-destructive test method for evaluating delamination defects in concrete by the Impact-echo test using multi-channel elastic wave data and to verify the validity of the proposed method by experimental studies in the laboratory. First, prototype equipment using an eight-channel linear sensor array was developed to perform elastic wave measurements on the surface of the concrete. In this study, three concrete slab specimens (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)), with simulated delamination defects of various lateral dimensions and depth, were designed and constructed in the laboratory. Multi-channel elastic wave signals measured on the three concrete specimens were converted to the frequency-phase velocity image by using the phase-shift method. A data processing method was proposed to extract the dominant propagating waves and non-propagating waves from the dispersion images. The dominant wave modes were used to evaluate delamination defects in concrete. It was demonstrated that the surface wave velocity values were useful for characterizing the shallow delamination defects in concrete. In addition, the peak frequency of non-propagating wave modes extracted from the dispersion images gives information on the lateral dimensions and depths of the delamination defects. This study also discussed the feasibility of combined use of the results from propagating and non-propagating wave modes to better understand the information on delamination defects in concrete. As will be discussed, the multi-channel elastic wave measurements enable more accurate, consistent, and rapid measurements and data processing for evaluation of delamination defects in concrete than the single-channel sensing method.


1998 ◽  
Vol 103 (C10) ◽  
pp. 21783-21793 ◽  
Author(s):  
Peter J. Stein ◽  
Steven E. Euerle ◽  
James C. Parinella

2011 ◽  
Vol 141 (6) ◽  
pp. 1121-1140 ◽  
Author(s):  
Habib Ammari ◽  
Lili Guadarrama Bustos ◽  
Hyeonbae Kang ◽  
Hyundae Lee

We consider a purely quasi-incompressible elasticity model. We rigorously establish asymptotic expansions of near- and far-field measurements of the transient elastic wave induced by a small elastic anomaly. Our proof uses layer potential techniques for the modified Stokes system. Based on these formulae, we design asymptotic imaging methods leading to a quantitative estimation of elastic and geometrical parameters of the anomaly.


Geophysics ◽  
2018 ◽  
Vol 83 (5) ◽  
pp. U51-U61
Author(s):  
Xufei Gong ◽  
Qizhen Du ◽  
Qiang Zhao ◽  
Pengyuan Sun ◽  
Jianlei Zhang ◽  
...  

Wave-equation datuming (WED) techniques have demonstrated superiority when waves occur on the acquisition surface nonvertically, and traditional static corrections based on the time shift become inaccurate. Meanwhile, as for multicomponent data, those scalar techniques can hardly maintain the vector characteristics for the following multicomponent data processing flows. Considering this, we have developed an elastic-wave datuming approach to handle the static corrections for multicomponent data. Different from those existing scalar WED techniques, the multicomponent data are first decomposed into multicomponent P- and S-wave data. Then, the decomposed data are transformed into the [Formula: see text]-[Formula: see text] domain, and they are extrapolated from the acquisition surface to the datum using the one-way elastic-wave continuation. Finally, the datumed multicomponent data are reconstructed at the output datum by adding up the datumed P- and S-wave data. This elastic WED can guarantee that the same wave modes on different components are equally datumed, and the data remain multicomponent so that they are still applicable to multicomponent-joint processing techniques. Finally, several test examples involved in this paper have proved our method’s effectiveness in multicomponent data datuming application.


2011 ◽  
Vol 340 ◽  
pp. 402-408 ◽  
Author(s):  
Ji Qi ◽  
Jing Hong Miao ◽  
Yu Xin Xie

In this paper the linear synthetic aperture focusing technique (SAFT), the nonlinear contrast source inversion (CSI) algorithm and the CSI algorithm with extended approaches, such as frequency approach and regularization approach, are applied to reconstruct a complicated target immersed in water from the experimental elastic wave data. The inversion results from these datasets using multi-bistatic measurement, which are obtained in the acoustic wave case and the pressure and vertically polarized shear (P-SV) wave case, verify the CSI algorithm with extended approaches is an accurate and promising method for elastic wave imaging.


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