Damage monitoring of aircraft structural components based on large-area flexible graphene strain sensors

Conventional sensors face limitations when it comes to monitoring damage on intricately curved surfaces of aircraft structures. In this study, a flexible graphene/polydimethylsiloxane (GNP/PDMS) strain sensor was fabricated using a mechanical coating method. The sensor exhibits characteristics of large-area, high strain capacity, and excellent sensitivity, while maintaining low cost and simplicity of manufacture. It is a highly scalable technology that can monitor structural deterioration and deformation. After optimization, a flexible GNP/PDMS strain sensor exhibits a maximum sensitivity of 251 and an average response time of 0.23 s at 5% strain. Furthermore, it maintains steady performance during 10,000 fatigue cycles, while effectively detecting bending and torsion. The application of this flexible GNP/PDMS strain sensor in monitoring crack initiation and propagation in specimens with hole-edge cracks during fatigue processes, as well as strain measurements on aircraft wing box sections and composite material structure component subjected to various forms of impact loading was both demonstrated. Experiments verified the GNP/PDMS sensor's capacity to locate fractures and track their progression in different specimens. The sensor has great potential for wide-ranging applications in important fields including aerospace, civil engineering, and robotic skins.