On the Effect of Geometric Nonlinearity on the Dynamics of Flared Folding Wingtips

Recent studies have considered the use of flared folding wingtips (FFWTs) to enable higher aspect ratios—reducing overall induced drag—while reducing gust loading and meeting airport operational requirements. The majority these analyses employed linear assumptions despite presence large wingtip deformations. In this paper effect geometric nonlinearities introduced by an FFWT on static dynamic aeroelastic response a wing is assessed. A geometrically exact expression was formulated describe change in local angle attack chordwise direction across all fold angles. This highlighted that aerodynamic stiffness and, therefore, quantities such as flutter speed are function hence, attitude wing. verified using both wind tunnel model flexible semispan numerical utilizing MSC Nastran, which linearized about equilibrium position wingtip. These experiments showed due deformations FFWTs can significantly affect dynamics system, with speeds varying over 28%, simply changing model.