LAUSR

Abstract Lamb waves are used in various non-destructive testing (NDT) and structural health monitoring (SHM) applications due to their velocity sensitivity to the properties of the material and their propagation over the entire thickness of the object over a long distance with low attenuation. However, the interpretation of the received signals is complex due to the Lamb waves dispersion nature, multiple mode generation, reflections and other. This work presents a novel method for the Lamb waves fundamental modes phase velocity dispersion evaluation and reconstruction these curves segments using only two signals measured at two close points. The carried out investigation using simulated signals was shown that the proposed method work with an extremely high accuracy - the mean relative error from the true values is less than 0.01%. The proposed method has been experimentally verified in two different mediums: isotropic - aluminium plate and anisotropic GFRP plate. The obtained results have indicated that the mean relative error from the true values is less than 1% in the aluminium case. The obtained results comparison with 2D-FFT method in the case of the GFRP plate has indicated that proposed method enables to reconstruct the phase velocity dispersion curves segments in the object of complex structure.