Impact Damage Detection on the Laminated Composite

Impact damage detection is critical for the utilization of composite materials. This paper investigates the applicability of active Lamb wave to composite damage monitoring. First, a time-reversal method has been adapted to guided-wave propagation to improve the detectability of local defects in composite plate structures. Second, a damage index (DI) method using a pair of sensors is introduced to generate index, which can be used to characterize the damage extent around the diagnostic path. Both of the methods proposed are validated through experimental studies in which different impact damages are generated by the falling a steel projectile on a laminated composite plate. The result showed that the methods may provide good correlation with the impact damage in the laminated composite plate.