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Title |
Development of Ultrasonic Scattering Wavefield Imaging Technique for Sub-Wavelength Damage in Concrete
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Authors |
민지영(Jiyoung Min) ; 김도윤(Do Yun Kim) ; 최하진(Hajin Choi) |
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DOI |
https://doi.org/10.4334/JKCI.2022.34.2.183 |
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Keywords |
비접촉; 누설 표면파; 산란파; 필터링 마스크; 파동장 air-coupled ultrasonic; Rayleigh wave; filtering mask; wavefield; scattering |
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Abstract |
In the non-destructive inspection of concrete structures, the ultrasound technique, one of classical methods, has been used to estimate crack depth and non-destructive strength by utilizing ultrasonic arrival time and speed. There is a limit to detecting sub-wavelength damage because of the heterogeneity of concrete and the size of large coarse aggregate. In this paper, a filtering mask to extract scattering waves reflected and refracted by microcracks was suggested, and the wavefield technique to visualize damaged images was developed. Ultrasonic signals were measured on concrete test specimens including sub-wavelength damage by utilizing MEMS-based multi-channel non-contact sensor array, and only scattering waves were extracted by applying the developed algorithm. The scattering wave energy reflected and refracted from the crack surface increased by 325.2 % compared to the no damage case, showing better performance than the conventional surface wave velocity method.
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