The Lamb waves phase velocity dispersion evaluation using an hybrid measurement technique

Abstract

In this paper two techniques: the zero-crossing and the spectrum decomposition are implemented together to obtain the guided waves phase velocity and their dispersion properties. This proposed hybrid technique has been investigated in two different mediums: an homogenous using signals obtain by 2D finite element modeling and experimental investigation and a non-homogenous environment using 3D finite element model. The results are compared with those obtained by the semi-analytical finite element method (SAFE). It was demonstrated that in the case of correctly selected filters the dispersion curves are reconstructed in approximately 90% for the Lamb wave A0 mode, for the non – dispersive S0 mode up to 81% of the incident signal frequency bandwidth in a homogeneous medium. In the case of non-homogenous CFRP plate the phase velocity dispersion curve of the A0 mode can be reconstructed even up to 96% incident frequency bandwidth.