Improved Performance of Morphing Shape Memory Polymer Skins

Morphing air vehicles are characterized by an ability to dramatically alter their airfoil characteristics to maintain optimal aerodynamic efficiency over a broad flight regime thereby broadening their mission profile over an equivalent fixed-wing vehicle. Essential to enabling these vehicles is a wing skin that is highly compliant in-plane for wing morphing while being highly stiff out-of-plane to carry aerodynamic loads. Shape memory polymers show substantial promise in meeting these conflicting requirements by allowing for dramatic changes in the material’s elastic modulus through the use of heat. However, critical to their application for morphing wing skins is efficient heat transfer enabling actuation of the wing skin within a timeframe that is consistent with vehicle flight control needs. Unfortunately, resistive heating methods traditionally used for shape memory polymers have thus far proven unable to meet this actuation rate requirement. As a result, the United States Air Force has significant interest in developing material for morphing wing skins that meets this actuation rate requirement. To address this need, ADA Technologies, Inc. proposes a multidisciplinary program that will result in novel means to achieve volumetric heating of the SMP morphing wing skin through electromagnetic induction. BENEFIT: The proposed program will result in shape memory polymer morphing skins that are characterized by unprecedented improvements in heating rate and magnitude, with triggering hardware that is lightweight and low in volume. The results of the proposed program will allow for novel flight control as well as broadening the mission profile of future air vehicles. Furthermore, the developments undertaken will substantially improve the state-of-the-art of adaptive materials. Thus if successful, the resulting technology could have substantial commercial impact as the overall market for unmanned air systems (UASs) is estimated to be in excess of billions per year. Spin-off applications include commercial applications of morphing wing skins for UASs such as gun and/or hand-launched unmanned air vehicles (UAVs) that range in size from 10 to 5000 lbs.