Aero-structural optimization of shape memory alloy-based wing morphing via a class/shape transformation approach

Abstract

Because of the continuous variability of the ambient environment, all aircraft would benefit from an in situ optimized wing. This paper proposes a method for preliminary design of feasible morphing wing configurations that provide benefits under disparate flight conditions but are also each structurally attainable via localized active shape change operations. The controlled reconfiguration is accomplished in a novel manner through the use of shape memory alloy embedded skin components. To address this coupled optimization problem, multiple sub-optimizations are required. In this work, the optimized cruise and landing airfoil configurations are determined in addition to the shape memory alloy actuator configuration required to morph between the two. Thus, three chained optimization problems are addressed via a common genetic algorithm. Each analysis-driven optimization considers the effects of both the deformable structure and the aerodynamic loading experienced by the wing. Aerodynamic considerations are addressed via a two-dimensional panel method and each airfoil shape is generated by the so-called class/shape transformation methodology. It is shown that structurally and aerodynamically feasible morphing of a modern high-performance sailplane wing produces a 22% decrease in weight and significantly increases stall angle of attack and lift at the same landing velocity when compared to a baseline design that employs traditional control surfaces.