Research On The Morphing Skins For Morphing Aircrafts

The study of morphing aircrafts emerged on the very dawn of the aviation era. By adapting theirshape to the changing flight environment the overall performance of aircrafts can be enhanced greatly.However, the pursuit of a promising morphing aircraft is doomed to meet quite a few problems, one ofwhich comes to the morphing skin that should be able to both transfer aerodynamic loads as an usualaircraft skin and be deformable as required. The paper summarizes the history of morphing aircraftsand morphing skins briefly, and proposes two kinds of morphing skin designs from the perspective ofcomposite materials.A novel type of composite named “honeycomb reinforced elastomer” is proposed according tothe features of honeycombs and polyurethane elastomer. After obtaining the constitutive law of thepolyurethane, a parametric study is conducted to analyze the skin by the finite element method, whichshows its feasibility to be anisotropic and is verified by the tensile test. Similarly, the fiber reinforcedelastomer is also investigated. Firstly, the single-layer fiber reinforced elastomer is fabricated andtested. Moreover, the multi-layer fiber reinforced elastomer is modeled and analyzed to represent therelationship between its morphing capacity, equivalent tensile modulus, non-dimensionalizeddeflection and its lamina angle, lamina thickness, fiber volume fraction.At last the two morphing skins are optimized with two different approaches respectively: theweight approach to transfer the sub-objectives of the honeycomb reinforced elastomer into one overallobjective and the multi-objective genetic algorithm to obtain the Pareto solution set and front of thefiber reinforced elastomer directly, after which a most suitable morphing skin design is selected basedon the analysis of a specific morphing structure.