Lamb wave based diagnostics of composite plates using a modified time reversal method

Lamb wave based diagnostics of composite plates using a time reversal method is investigated. Composite plates are impacted by a steel ball from various heights to cause increasing levels of damage. A transducer array, consisting of PZT patches, is used to send and receive A0 Lamb waves. Wavelet analysis is used to denoise and clean up the received signals. For each actuator-sensor pair, the time reversal procedure is conducted. Based on the comparison between the actuated signal and the signal received after time reversal, a damage index is computed and outlying damage index values are used as a basis for damage detection. Preliminary results show that the method can detect presence, location and intensity of damage. Fur- ther experiments are planned to investigate sensitivity and consistency of damage detection.

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