Lamb Wave Line Sensing for Crack Detection in a Welded Stiffener

Sensors

Yun-Kyu An¹  Jae Hong Kim² 

[1] International Institute for Urban Systems Engineering, Southeast University, Nanjing 210096, China; E-Mail:;School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798, Korea; E-Mail:

关键词: nondestructive testing;    structural health monitoring;    Lamb wave crack detection;    line sensing;    welded stiffener;    frequency-wavenumber analysis;   

DOI  :  10.3390/s140712871

来源: mdpi

【 摘 要 】

This paper proposes a novel Lamb wave line sensing technique for crack detection in a welded stiffener. The proposed technique overcomes one of the biggest technical challenges of Lamb wave crack detection for real structure applications: crack-induced Lamb waves are often mixed with multiple reflections from complex waveguides. In particular, crack detection in a welded joint, one of the structural hot spots due to stress concentration, is accompanied by reflections from the welded joint as well as a crack. Extracting and highlighting crack-induced Lamb wave modes from Lamb wave responses measured at multi-spatial points along a single line can be accomplished through a frequency-wavenumber domain analysis. The advantages of the proposed technique enable us not only to enhance the crack detectability in the welded joint but also to minimize false alarms caused by environmental and operational variations by avoiding the direct comparison with the baseline data previously accumulated from the pristine condition of a target structure. The proposed technique is experimentally and numerically validated in vertically stiffened metallic structures, revealing that it successfully identifies and localizes subsurface cracks, regardless of the coexistence with the vertical stiffener.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.