Identifying the arrival of extensional and flexural wave modes using wavelet decomposition of ultrasonic signals

In health monitoring applications of composite materials, the health state of specimens is often evaluated using naturally occurring and simulated Acoustic Emission stress waves. For such applications, identifying the arrival times of the extensional and flexural wave modes from acquired signals is a crucial step, and must be performed reliably and potentially on large sets of signals. This article proposes using the wavelet decomposition of a signal to develop a fast, algorithmic and automated approach to estimate the arrival times of the extensional and flexural wave modes. Algorithms are developed that estimate the two arrival times using wavelet decomposition data, and which can be employed to consistently and reliably identify the arrival times from large sets of signals iteratively. MATLAB scripts to automatically execute the algorithms are also developed, and are made available online.