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Lamb‐wave‐based structural health monitoring technique for inaccessible regions in complex composite structures
Author(s) -
M. Janardhan Padiyar,
Balasubramaniam Krishnan
Publication year - 2014
Publication title -
structural control and health monitoring
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.587
H-Index - 62
eISSN - 1545-2263
pISSN - 1545-2255
DOI - 10.1002/stc.1603
Subject(s) - structural health monitoring , lamb waves , delamination (geology) , acoustics , mode (computer interface) , ultrasonic sensor , structural engineering , joint (building) , engineering , instrumentation (computer programming) , finite element method , materials science , computer science , telecommunications , surface wave , physics , geology , paleontology , subduction , tectonics , operating system
SUMMARY This work investigated feasibility of Lamb wave based SHM technique for in‐situ monitoring of hidden (inaccessible) web region, for delamination type of defect, in a typical stiffened composite (I‐joint) section of an aircraft structure. Finite element model was proposed to understand and compare the wave propagation of fundamental symmetric Lamb mode (S 0 ) through a healthy and center delaminated web of the I‐joint. In simulations, S 0 mode was excited at the center of web, which then, travels along the web and propagates into skin regions of the I‐joint. Turning modes were also observed. From the S 0 mode captured at two locations on the skin, one for the direct mode and another for the turning mode, it was seen that amplitude of the captured mode can used as a feature for delamination detection. Experiments were carried out on the I‐joint with bonded piezoelectric wafer active sensor patch on the web and skin regions. In order to reduce the weight of the SHM instrumentation, an attempt was made to develop a low footprint, portable instrumentation for actuation, and reception of Lamb waves and wireless live transmission of the ultrasonic data. Experimental measurements showed a similar trend of significant decrease in the amplitude of S 0 modes when propagating through the web delamination when compared to simulation. Copyright © 2013 John Wiley & Sons, Ltd.