Structural Health Monitoring of an Aircraft Wing Using a Portable Wireless Electro-Mechanical Impedance Analyzer

Electro-mechanical impedance (EMI)-based structural health monitoring (SHM) method has received the widespread attention in aerospace engineering. Nevertheless, commercial impedance measurement instruments are difficult for in-situ field applications to aircraft structures due to their bulkiness and high power-consumption. There is an urgent need to develop portable impedance measurement devices in order to popularize EMI-based SHM method from laboratories to practical applications. In this paper, a portable wireless impedance analyzer is proposed to improve the practicability of EMI-based SHM method. The analyzer allows for multi-channel impedance measurement of piezoelectric transducers (PZTs) with adjustable calibration resistors and the ambient temperature measurement of PZTs. The power-consumption of analyzer when performing the tasks was first assessed. Also, the robustness of wireless communication of analyzer was then evaluated based on the received signal strength indicator and packet loss rate. Subsequently, the ambient temperature and the impedance spectra of PZTs were measured using the analyzer. Additionally, a wing of an unmanned aerial vehicle was selected as the test structure, and the feasibility of analyzer to detect aircraft structural damages at the leading edge was validated. The proposed analyzer features high integration and low power-consumption. It is anticipated that a wireless monitoring network based on the analyzer can be established to implement field applications of the EMI-based SHM method in aircraft structures.