Optimal design of smart conformable airfoil sections

Variable or controllable camber on an airfoil can improve performance of fixed-wing and rotary-wing aircraft, as well as reduce vibration and noise for helicopters, when applied cyclically. Although currently a subject of research, variable camber airfoils are regarded as the successors to airfoils with trailing edge flaps and are attractive as they do not have exposed linkages and high drag. In the present study, smart materials (piezoelectric materials) are optimally distributed over the section of the airfoil aft of the spar, to produce the desired camber. One challenge in this problem lies in the fact that the airfoil is simultaneously required to be compliant so it deforms under actuation loading, yet rigid so it retains its profile under aerodynamic surface pressures. The second challenge lies in obtaining significant deformations using piezoelectric actuators which inherently deliver very small strains. The optimal topology, together with carefully designed skins, is crucial to the successful solution of the problem.