Design Principles for Geometrically Anisotropic Thermoplastic Rubber Morphing Aircraft Skins

This paper introduces a new design concept for morphing aircraft skins which combines three key design principles to create compliance-based morphing structures that are capable of large morphing deformations. These skins take advantage of additive manufacturing methods and thermoplastic elastomers of different stiffnesses to allow for strategic placement of stiffness and compliance, taking advantage of geometric anisotropy and design scaling laws to create better compromises between the need for low in-plane stiffness to reduce actuation energy and high out-of-plane stiffness to resist aerodynamic loads. The three design principles are first introduced, after which design possibilities for a family of different morphing components based on these principles are explored. Initial prototypes are shown, and a range of considerations related to manufacturing, design, and integration are discussed. Finally a multiobjective design optimization study using low fidelity models of the skin structures shows some of the potential advantages of this approach.