Shape sensing approach for composite and sandwich beam with generic cross-sections: Application to fiber-reinforced polymer composite airfoil

This paper proposes a shape sensing methodology to establish the deformation reconstruction model for the composite-airfoil structures by using discrete surface strain measurements. The method employs the inverse Finite Element Method (iFEM) as a general framework and Refined Zigzag Theory (RZT) as refined theory to describe the deformation field of the composite-airfoil structure, where the effects of the cross-sectional variation in theoretical shear strain distribution due to transverse loads and the cross-sectional distortions deformation are accounted in the proposed iFEM formulation. The reconstruction capacity of the proposed approach was demonstrated through the UAV airfoil structure under distributed load, where the strain variation functions and profile functions are determined based on finite element analysis. The numerical results show the proposed shape sensing method presents much greater reconstruction accuracy with respect to the previous homogeneous iFEM method, where the reconstruction error is less than 2% and improved by 7%. Thus, the proposed iFEM method can be used as a powerful tool for both shape sensing and structural health monitoring of the airfoil structure that are instrumented with embedded strain-sensing systems.