On the Prediction of Guided Wave Dispersion Curves in Plates for Health Monitoring Applications

In the last years, a significant interest has been pointed out in the capability of ultrasonic guided waves as candidate tool for structural health monitoring (SHM), due to their high damage detection sensitivity and low power consumption. The monitoring of the structural health through the propagation of guided waves is complex: some wave phenomena, namely dispersion and slowness, together with boundary scattered waves, may mask the presence of damages. So, studying the dispersion phenomenon through the dispersion curves may be helpful in understanding the propagation mechanisms. As Lamb waves dispersion equations do not generally have analytical solutions, the development of a predictive finite element (FE) model can be a valuable tool for the improvement of SHM systems, avoiding the high cost of experimental campaigns. Thus, once calibrated with respect to an experimental test case, the developed FE model can be used to simulate and predict guided-wave propagation mechanisms in a given structure. This leads to the possibility of employing such approach to identify and localize potential structural damages, that is the final aim of an SHM system. In this work, the FE method, together with an in-house code, has been used to investigate guided wave dispersion phenomenon in plates for possible SHM applications.