Damage detection in a large composite panel of five stiffeners using Lamb wave signals

The propagation characteristics of Lamb waves activated and collected by an active piezoelectric (PZT) sensor network in a CF/EP composite panel of five stiffeners were investigated. In particular, wave attenuation in terms of propagation distance and wave energy loss induced by reinforced stiffeners were evaluated. The interaction between Lamb wave modes and a through-thickness hole of 11.9 mm diameter was subsequently examined. Given the complexity of the captured wave signals, an inverse algorithm based on correlation between wave signals in the benchmark and damaged structures was developed. Different combinations of actuator-sensor paths were used to estimate the location of damage. The diagnostic results demonstrate that the proposed approach has a good capability for defining location of damage using the probability of occurrence of damage.