Composite Diagnostics with Use of Embedded PZT Transducers—A Smart Structure Example

Abstract

Application of guided waves excited by a network of PZT transducers integrated with a given structure is one of the promising approaches to Structural Health Monitoring (SHM). The performance of a SHM system based on PZT network is rooted in two distinct areas of the technology development, that is: the hardware and the signal analysis. The first includes is the type of transducers used to built a network and the way of their integration with a monitored structure. For composites, beside the possibility of the transducers attachment to a surface of an element, also immersing of PZTs into their internal structure is available. In the article Barely Visible Impact Damage (BVID) detection capabilities of the embedded and surface attached PZT transducers are compared in broad frequency range of the excitation. The damage detection capabilities are compared in the range 100 – 350 kHz. In addition to purely qualitative detection of damages a new algorithm of their localization is proposed and compared between the embedded and surface attached transducers for the frequency optimal to detect BVIDs. This algorithm is a modified version of the RAPID imaging method, but suitable to be used also in the case of non-homogeneous sensor networks. Finally the performance of a system is verified with use of a composite panel having PZT transducers embedded into its internal structure. The network geometry was tailored to fulfill specific demands regarding the structural performance. doi: 10.12783/SHM2015/72