Optimal excitation frequency for delamination detection in cross-ply laminated beams using A0 lamb mode

For enhancing the reliability and robustness of structural monitoring techniques based on Lamb waves, numerical investigations on optimal excitation frequency of actuators of piezoelectrics, which may lead to very strong or even the strongest reflected signals from a delamination in cross-ply laminated beams, have been carried out in this paper. In practical applications, the strong reflected signals from the delamination influenced weakly by experimental noises can be easily employed to identify the delamination position plus the information of wave propagation speed. The present numerical analysis is based on the Chebyshev pseudospectral element method proposed by the present authors. In this study, A(0) mode in Lamb waves, which was validated to be suitable for detecting tinny defects, is employed for this purpose. Through a large amount of numerical calculations, the optimal excitation frequencies corresponding to various delamination lengths are obtained.