A built-in active sensor network for health monitoring of composite structures

Abstract

An embedded sensor network technique was developed for improving the overall integrity offunctionalized composite structures engaged in aircraft. A set of miniaturized piezoelectricwafers was designed and circuited to configure a built-in active actuator/sensor network,which was immobilized into multi-layered composite laminates. The propagationcharacteristics of Lamb waves generated and collected by this built-in sensor network incarbon fibre-reinforced composite laminates were investigated. The influence of a stiffenerand of the excitation frequency on the propagation of the Lamb waves generated wasevaluated. A study was carried out to assess delamination in CF/EP (carbonfibre/epoxy) woven laminates, by fusing information from multiple sensing paths ofthe embedded network on the basis of the Hilbert transform, signal correlationand probabilistic searching. An excellent identification capability indicates theconsiderable application potential of the proposed sensor network approach in providinghigh-fidelity data acquisition and condition monitoring for composite aircraft structures.