Modeling and experimental detection of damage in various materials using the pulse-echo method and piezoelectric sensors/actuators

The application of guided wave techniques to nondestructively determine the structural integrity of various engineering materials, like alumina, laminated composites, and composite sandwiches, is presented. In particular, a combined theoretical, numerical, and experimental investigation of the fundamental aspects 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 internal damage 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. The effects of frequencies, wave forms, and types of piezoelectric material on the damage detection process are discussed, in consideration of locating damage in structures. 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.