Rotational bistable mechanisms for morphing wings and beyond.

Low-energy-use morphing structures can greatly impact various engineering disciplines. In aeronautics, aircraft wings must adapt to diverse flight conditions to ensure optimally shaped wings for enhanced performance, maneuverability, and efficiency. Shape morphing enables aircraft to maximize aerodynamic performance but often requires complex system designs with heavy components, leading to continuous energy consumption and reduced payload capacity. To address these challenges, we introduce a new class of additively manufactured, bistable rotating elements designed for aircraft wing structures. Leveraging geometric nonlinearity, our proposed design creates bistable geometries that enable substantial and reversible alterations in the wing's chordwise geometry. This eliminates the need for continuous energy use during various maneuvers, thus conserving fuel or battery usage and contributing to weight reduction, particularly in Uncrewed Air Vehicles (UAVs). The proposed multistable morphing wing offers mechanical and geometric tunability, allowing for precise adjustments in stiffness and degrees of rotation. Experimental validation, including wind tunnel tests, and Finite Element Analysis confirm the mechanical reliability of the multistable rotational morphing wing. Demonstrating its ability to maintain the morphed shape across various flight conditions, this concept shows promise for enhancing UAV performance in real-world applications and extending its potential to fields beyond aerospace engineering.