Strain measurements of an aircraft wing using embedded CNT fiber sensor and wireless SHM sensor node

Composite material-based aircraft structures have attracted attention due to their lightweight and superior mechanical properties. However, composite structures have a high risk of structural failures when damages occur due to loadings or impacts. Therefore, consistent structural health monitoring (SHM) is needed to ensure the structural integrity and safety of the aircraft. Various methods of sensor installation and measurement systems were developed for the implementation of SHM in aircraft structures. In this research, the carbon nanotube (CNT) fiber sensor was optimized by comparing the different configurations such as carbon black concentration, polyurethane layer, and dip-coating iterations. Glass fiber reinforced plastic skin with embedded CNT fiber sensor was implemented on a 1700 mm long right main wing. Strain measurements were performed during static loadings through the wireless SHM sensor node. Strain measurement due to resistance change during temperature decrease was also performed to investigate the effect of temperature on the CNT fiber sensor. The CNT fiber sensor showed comparable strain measurement results to conventional strain gauge strain measurements. Consequently, the CNT fiber sensor and the wireless SHM sensor node showed new possibilities for embedded sensor applications and real-time SHM implementations for aircraft structures.