A Two-Level Approach for the Optimal Design of Morphing Wings Based on Compliant Structures

The great interest in developing morphing airfoils is mainly based on their capability to adapt their shape to optimize some specific aircraft performance indices during the mission. Nevertheless, the design of these kinds of devices requires the availability of ad hoc-developed procedures able to tackle the conflicting requirements such as the high deformability requested to change the airfoil shape coupled to the load-carrying capability and to the low weight. The article proposes an approach for optimal airfoil-morphing design based on a compactapproach to describe the airfoil geometry coupled to a two-level optimization procedure. In the first one, the best deformed airfoil configuration is determined as the most efficient aerodynamic shape which at the same time limits the requested energy to deform the airfoil skin. In the second optimization level, the best internal structural configuration is obtained using an ad hoc-developed topology optimization tool based on genetic algorithms that synthesize a compliant structure able to adapt itself in order to match the optimal shape coming out from the first level. The procedure has been applied to design the morphing leading and trailing edges for an NACA 63_2215 airfoil.