Differential Time of Arrival estimation by processing the highest magnitude components of impact's generated ultrasonic guided wave signals

Impacts on critical structures can be monitored by using piezoelectric sensors of patch type. The sensors detect the ultrasonic guided waves (UGW) propagating into the platelike structure; typically, So and Ao mode Lamb wave are the most used modes for localizing the impact point and derive other information about the impact velocity and energy. Ao is generally preferred being the most energetic with high amplitude spectral components in the low frequency range (below 100 kHz) but is also dispersive. Continuous Wavelet Transform (CWT) is commonly adopted to extract information from these dispersive signals. We studied a method based on CWT bear in mind the implementation of a real-time impact monitoring system, where response speed and computational resources can be limited.