Multifunctional composite kirigami skins for aerodynamic control.

The development of low-altitude unmanned aerial vehicles (UAVs) has been proposed for many high-impact civilian-centered applications such as expanding telecommunication networks in remote locations, improved weather monitoring, and terrain surveying. Such missions, which can last anywhere from hours to days, rely on efficient, lightweight, and high-aspect ratio designs to minimize energy consumption. We investigate a method of aerodynamic control that also permits energy harvesting through surface texturing on aircraft wings using multifunctional kirigami composites. These kirigami skins produce 3D surface features when axially strained and have been manufactured using thin-film solar cells. Here, we show that when actuated, these 3D features increase the drag over the wings, which can be used to control yaw. Wind tunnel experiments were conducted to quantify the effects of kirigami actuation on aerodynamic lift, drag, and yaw moment. These results demonstrate excellent yaw-control capabilities and delayed aerodynamic stall, indicating that the actuated kirigami features may delay flow separation. The implied multifunctionality of these kirigami skins is ideal for low-altitude UAVs, which benefit from both lightweight energy sources and actuators. [ABSTRACT FROM AUTHOR]