Identification of delamination position in cross-ply laminated composite beams using S0 Lamb mode

In this work, a Lamb wave based technique has been developed for delamination detection in cross-ply laminated beams. By measuring the propagation speed of S0 Lamb mode and the traveling time of a signal reflected from a delamination site, the location of the delamination can be identified. It has been also confirmed by the experiment that the location of a delamination can be accurately determined by only using the data collected from the sensors in a defect-containing beam, without referring to the baseline signals. Finally, to gain a better understanding of the complex interaction between a Lamb wave and a long delamination, numerical simulations have been carried out using finite element method (FEM). The signal modes generated at the boundaries of the delamination have been analyzed.