Application of a baseline-free damage detection technique to complex structures

Changgil Lee; Seungbum Kim; Hoon Sohn

doi:10.1117/12.815703

30 March 2009 Application of a baseline-free damage detection technique to complex structures

Changgil Lee, Seungbum Kim, Hoon Sohn

Proceedings Volume 7292, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2009; 729221 (2009) https://doi.org/10.1117/12.815703
Event: SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring, 2009, San Diego, California, United States

Abstract

Recently, a reference-free damage detection technique that does not rely on baseline data has been proposed for plate-like structures by the author's research group. If Lamb waves traveling along a thin plate encounter damage such as crack and corrosion, mode conversions occur. Using the previously developed reference-free technique, it has been shown that the mode conversion due to damage formation can be detected without using baseline data. In this study, the previous technique is further advanced so that it can be applied to structures with complex geometries such as a stiffener and thickness variations. First, the applicability of the proposed technique to a plate with a stiffener is tested. Due to the stiffener in the wave path, mode conversion is produced even in the absence of damage. Next, the effect of the plate thickness variation is investigated. When Lamb waves propagate along a symmetrically tapered section, mode conversion can be also produced. However, due to symmetry of waveguide, converted modes cancel out each other and no special treatment is necessary. On the other hand, non-symmetric thickness variation can cause the mode conversion even in the absence of the defect. Since feature observed from the non-symmetrically tapered plate is the most complex to analyze, this case is highlighted in this study. Furthermore, an instantaneous damage classification method has been developed. Experimental studies as well as numerical simulations are executed to investigate the effectiveness of the proposed technique.

Citation Download Citation

Changgil Lee, Seungbum Kim, and Hoon Sohn "Application of a baseline-free damage detection technique to complex structures", Proc. SPIE 7292, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2009, 729221 (30 March 2009); https://doi.org/10.1117/12.815703

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