Research on Variable Sweepback Angle of Winglet Driven by Shape Memory Alloy

Abstract

Because of its shape memory effect, shape memory alloy (SMA), as a driver, provides more possibilities for the design and optimization of winglets of variable sweepback angle. In view of three different flight states of a large civil aircraft, i.e. take-off, cruise and landing, the effects of different winglets of variable sweepback angle on the aerodynamic performance of the aircraft are analyzed by computational fluid dynamics (CFD), and then the optimal sweepback angles are 35°, 45° and 50° respectively. Based on the change of the sweepback angle of winglets in different flight states, a variable sweepback winglet structure based on SMA wire is designed. Combined with SMA constitutive relation, SMA driving mechanism is designed by the coupling method of force, heat and strain. The mechanism can automatically adjust the swept angle of winglets according to different flight conditions, so as to improve the lift drag ratio of wings.