Aeroelastic analysis of a flared folding wingtip with free-play nonlinearity

Abstract Flared folding wingtips (FFWTs) are designed to deform adaptively, managing flight loads more efficiently, potentially reducing structural weight, and contributing to enhanced fuel efficiency and payload capacity, but this comes at the expense of nonlinearity. Reported here is a nonlinear aeroelastic response analysis of the free-play nonlinearity of an FFWT. The fictitious-mass approach is used to model the free-play modes, with suitable fictitious masses selected iteratively. Nonlinear flutter analyses are conducted for the flare and free-play angles, and a comprehensive analysis is conducted of how varying them affects the limit-cycle oscillations (LCOs). When the free-play angle is 0.1°, both the leading edge and the wingtip of the hinge line show limit cycle oscillation, and the oscillation amplitude of the wingtip is ten times that of the leading edge. By leveraging the nonlinear adaptive properties of FFWTs, future aircraft can achieve enhanced aerodynamic performance, reduced operating costs, and improved adaptability across a range of flight scenarios.