Impact event identification is a primary concern in many structural health monitoring applications. Model-based inverse
analysis is a common approach for system identification as long as the physical model can accurately capture the
behavior of structure. A layered analysis including estimation of impact location (IL) in the first layer and reconstruction
of impact load time history (ILTH) in the second layer was proposed. An implementation of the theory on a simply
supported plate structure is conducted in this study. The results indicate that the proposed inverse scheme is capable of
detecting impact location and reconstructing impact load time history with a satisfactory precision. Due to presence of
system error, a suitable cost function has to be chosen to guide the fitting process toward the desired parameters.
In this study, the guided wave technique is applied to nondestructively assess the damage in various engineering materials, like alumina, laminated composites, and composite sandwiches. A combined theoretical, numerical and experimental investigation of the pulse-echo method using piezoelectric sensors and actuators is conducted. The dispersion effect of wave guides on these materials is first analyzed, and the transient propagation process of wave guides and its interaction with inside damages are then numerically simulated. The implementations of the pulse echo method are illustrated in experimental testing and damage detection of aluminum beams, carbon/epoxy laminated composite plates, and composite sandwich beams. In particular, the experimental results on damage detection of the composite sandwich beams are reported and discussed. As illustrated in this study, the pulse-echo method combined with piezoelectric material can be used effectively to locate damage in various engineering materials and structures.