Characterization and compaction of Lamb wave data using a combination of S and wavelet transformations

During the interpretation of the Lamb wave data, the main concern is often the arrival times of wave groups. Group arrival times determine the distance of the source or the reflector. The inspection of sensory signal envelopes is satisfactory to identify and localize defects. The S-transformation is proposed for isolating wave forms at their excitation frequency and obtaining their envelopes. To further minimize the storage and computational costs, reduction of the data size by down sampling (skipping 5 data points for each saved one) and compression via calculating the wavelet transformation three times are proposed. The data was reduced to 1/30th of its original size, while the reconstructed wavelet transformation had a less than 1% average error with respect to the down sized envelope signal. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Duke Scholars

Author Liming Salvino Civil and Environmental Engineering