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Comparative study of nonlinear acoustic and Lamb wave techniques for fatigue crack detection in metallic structures
Author(s) -
RYLES M.,
NGAU F. H.,
MCDONALD I.,
STASZEWSKI W. J.
Publication year - 2008
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.2008.01253.x
Subject(s) - materials science , lamb waves , acoustics , structural engineering , transducer , wave propagation , engineering , optics , physics
The paper deals with fatigue crack detection in metallic structures. A simple fatigue experiment is performed to initiate and propagate a crack in an aluminium plate. The plate is instrumented with two low‐profile piezoceramic transducers and one low‐profile piezoceramic stack actuator. Nonlinear acoustics and Lamb waves are used for crack detection. The former utilizes the high‐frequency acoustical wave and low‐frequency modal excitation for damage detection. Modulations sidebands around the acoustical spectral component are used to detect the crack. The latter produces Lamb wave responses that are de‐correlated due to the presence of the crack. Both effects are due to growing fatigue crack. Two simple signal parameters, namely the intensity of modulation and the normalized cross‐correlation coefficient are used as damage indicators. The study demonstrates similar sensitivity of both methods to small fatigue cracks.