Optimized design of an active extrados structure for an experimental morphing laminar wing

This paper focuses on the design of an active extrados structure for an experimental morphing laminar wing, which has been tested in a subsonic wind tunnel. Actuators localized inside the wing box apply individually controlled displacements over the flexible structure, made from laminate composite, to modify the airfoil profile in accordance with the database, which is built using XFoil aerodynamic solver. This database contains a set of wing profiles, which maximize laminar flow under a given set of cruise flight conditions: Mach number 0.2 to 0.35 and attack angles −1 to 2°2°. A finite elements structural model of the active extrados has been developed with ANSYS software. Two main design parameters were identified: the number of plies in the composite laminate of the flexible extrados and the number of actuators. To balance the tradeoff between stiffness and flexibility of the active extrados structure, aerodynamic (laminar flow regime enhancement) and mechanical (low strain energy) performance criteria were considered simultaneously. Using the multi-objective optimization technique, the designer's preferences led to the selection of the 4-ply 2-actuator active extrados structure configuration.