Detection of high-order Lamb waves using an end-face injection of ultrasonic pulses

Abstract

In this work, we report the time-of-flight detection of high-order Lamb waves by using an end-face injection of ultrasonic pulses in plates. We used two piezoelectric transducers attached to the opposite edges of a rectangular plate. We applied the Short Time Fourier Transform (STFT) to determine the time-of-flight. We compare the contours of the STFT on the time-frequency spectrogram with the theoretical time-of-flight. This technique defines a broadband map for multiple Lamb waves on the same experimental run. We have found clear evidence not only of the lowest symmetric and antisymmetric modes (S0 and A0) but also of higher order modes (S1, A1, and S2).