Fabrication, characterization, and modeling of a structural flexible skin for applications in morphing wings

Abstract

One of the aircraft components with high potential for improvement in functionality is the wing. For novel wings with morphing capabilities, their skin must be able to support internal and external loads while being sufficiently flexible. The goal of this work is to fabricate, characterize, and model a novel structural flexible skin. The material structure of the proposed skin is formed by a laminated composite of two layers of silicone elastomer and one layer of nylon 6.6 fabric. The advantages of the proposed skin include low production costs, lightness, structural simplicity, and stiffness in one direction while having flexibility in the other direction. Samples of the raw fabric and the silicone elastomer are fabricated and subjected to uniaxial tensile tests. Numerical simulations are conducted to calibrate various hyperelastic models describing the non-linear elastic response of the raw fabric and the elastomer. The experimental tests on the raw fabric and the composite skin indicate that the proposed composite skin is suitable for chordwise flexibility of an airfoil. The application of the proposed skin with its bias direction along the chordwise direction of the airfoil on the upper surface shows the improvement of the functionality and surface uniformity of the airfoil.