Morphing Aircraft Sizing Using Design Optimization

This paper summarizes design optimization approaches for sizing a morphing aircraft for which the wing can make significant shape changes in flight. The approaches include single-level problems solved by gradient-free and gradient-based optimizers and a multilevel problem solved by gradient-based optimizers; of these, the multilevel approach proved most efficient. In the multilevel approach, a top-level problem minimizes the aircraft gross weight using reference design variables (T=W, S, AR, t=c, � , and � ), along with morphing limit variables describing the maximumshapechangeasafunctionofthereferencegeometry (e.g., � b, � c,and �� ).Asublevelproblemforeach mission segment determines an optimal wing-shape scheduling that minimizes fuel consumption, satisfies performance constraints, and operates within the geometric domain prescribed by the top-level problem. While the empty-weight buildup uses traditional predictors for fixed-geometry components, the wing weight prediction uses a parametric equation derived from structural optimization studies of morphing wings. The multilevel optimization approach then sizes an aircraft for which the wing can change sweep and root chord length, demonstrating: 1) the optimal wing-shape scheduling and maximum shape change for the morphing strategy, 2) the approach’s ability to facilitate continuousmorphingduringmissionsegmentanalysis,and3)improvedeffectiveness overprevioussinglelevel morphing aircraft sizing approaches.