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Proceedings Paper

Non-contact visualization of nonlinear ultrasonic modulation for reference-free fatigue crack detection
Author(s): Hyung Jin Lim; Byeongju Song; Byeongjin Park; Peipei Liu; Hoon Sohn
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Paper Abstract

This paper presents a fatigue crack detection technique based on visualization of nonlinear ultrasonic wave modulation produced by a fatigue crack. When distinctive low frequency (LF) and high frequency (HF) inputs are generated and applied to a structure, the presence of a fatigue crack can provide a mechanism for nonlinear ultrasonic modulation and create spectral sidebands around the frequency of the HF signal. In this study, the two input signals are created by two air-coupled transducers (ACT), and the corresponding ultrasonic responses are scanned over a target specimen using a 3D laser Doppler vibrometer (LDV). The crack-induced spectral sidebands are isolated using a combination of linear response subtraction (LRS), and continuous wavelet transform (CWT) filtering. Then, the extracted spectral sideband components are visualized near the fatigue crack. The effectiveness of the proposed non-contact scanning technique is tested using an aluminum plate with a real fatigue crack.

Paper Details

Date Published: 8 March 2014
PDF: 7 pages
Proc. SPIE 9061, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2014, 90611B (8 March 2014); doi: 10.1117/12.2046182
Show Author Affiliations
Hyung Jin Lim, KAIST (Korea, Republic of)
Byeongju Song, KAIST (Korea, Republic of)
Byeongjin Park, KAIST (Korea, Republic of)
Peipei Liu, KAIST (Korea, Republic of)
Hoon Sohn, KAIST (Korea, Republic of)

Published in SPIE Proceedings Vol. 9061:
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2014
Jerome P. Lynch; Kon-Well Wang; Hoon Sohn, Editor(s)

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