Stretchable sensing skin with S-shape multicore optical fiber implantation for morphing flight vehicles

The smart structures and skins have wide application prospects in future morphing aircrafts and spacecrafts and have attracted much attention in recent years. This paper proposes a stretchable sensing skin with S-shape multicore optical fiber implantation. Different from previous approaches, the multicore fiber with FBG sensor array is embedded into a super elastic substrate in S-shape to form a stretchable sensing skin. This S-shape configuration makes the optical fiber stretchable enough to deform with the skin, and using the multi-core configuration, various types of fiber sensors can be inscribed on different fiber cores to measure the skin shapes and external loads. The sensing characteristics of the skin and the shape sensing of a morphing wing prototype is demonstrated, and the nonlinear characteristics and relaxation of the sensing responses are analyzed. The 3D shapes of a morphing wing prototype are measured at four airfoil profiles using the stretchable sensing skin, the results are verified by visual measurements. The proposed stretchable sensing skin should have broad application prospects in future morphing flight vehicles.