Damage assessment in composites by Lamb waves and wavelet coefficients

A wavelet technique was used in an active system for the damage detection of aerospace composites. The active system was based on the generation and reception of Lamb waves by embedded piezoceramic transducers. The wavelets were used to decompose the Lamb-wave response into wavelet coefficients. The decomposition performance was improved by utilizing more adapted wavelets, based on the recurrent waveforms of Lamb waves. The changes in the Lamb waves interacting with damage in the plate were successfully characterized by this wavelet technique, through the amplitude change of the wavelet coefficients. The wavelet technique also showed great sensitivity in detecting damage of small sizes. This technique was found to be straightforward for detection of impact damage and evaluation of the damage size.

[1]  Sébastien Grondel,et al.  Fatigue crack monitoring of riveted aluminium strap joints by Lamb wave analysis and acoustic emission measurement techniques , 2002 .

[2]  Daniel L. Osmont,et al.  Active health system based on wavelet transform analysis of diffracted Lamb waves , 2000, Symposium on Applied Photonics.

[3]  Wieslaw J. Staszewski,et al.  Advanced data pre-processing for damage identification based on pattern recognition , 2000, Int. J. Syst. Sci..

[4]  Yao-Jun Wu,et al.  Fusion of Wavelet Packets and Neural Network in Detection of Composites , 2000 .

[5]  Paul D. Wilcox,et al.  Mode and Transducer Selection for Long Range Lamb Wave Inspection , 1999 .

[6]  W. J. Staszewski,et al.  Structural and Mechanical Damage Detection Using Wavelets , 1998 .

[7]  S. Mallat.  A wavelet tour of signal processing , 1998 .

[8]  G. Tomlinson,et al.  Wavelet signal processing for enhanced Lamb-wave defect detection in composite plates using optical fiber detection , 1997 .

[9]  Peter Cawley,et al.  Long range propagation of Lamb waves in chemical plant pipework , 1997 .

[10]  William B. Spillman,et al.  In-situ damage monitoring of composite structures , 1996, Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[11]  Ronald R. Coifman,et al.  On local feature extraction for signal classification , 1996 .

[12]  Truong Q. Nguyen,et al.  Wavelets and filter banks , 1996 .

[13]  P. Cawley,et al.  The interaction of Lamb waves with delaminations in composite laminates , 1993 .

[14]  P. Cawley,et al.  The interaction of Lamb waves with defects , 1992, IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control.

[15]  I. Daubechies.  Orthonormal bases of compactly supported wavelets , 1988 .

[16]  S. Rokhlin,et al.  Diffraction of Lamb waves by a finite crack in an elastic layer , 1980 .