Nonlinear Aeroelastic Response of Strut-Braced High Aspect Ratio Wings

Abstract High Aspect Ratio Wings (HARW) are widely used in commercial aviation due to their superior lift-to-drag ratios and extended flight ranges, which enhance fuel efficiency. However, their increased aspect ratio introduces structural challenges such as higher stress at the wing root and greater flexibility, leading to significant deflections that affect aeroelastic behaviour. Strut-Braced High Aspect Ratio Wings (SB-HARW) have been proposed to mitigate these issues, offering potential advantages over conventional designs. Despite their promise, SB-HARW experience large deflections that introduce structural nonlinearities, significantly influencing aeroelastic stability and dynamic response. Limited research exists on the nonlinear aeroelastic behaviour of SB-HARW, particularly in the post-flutter regime, hindering their practical application in commercial aviation. This study investigates the nonlinear aeroelastic response of SB-HARW beyond flutter instability, accounting for wing and strut nonlinearities. The wing is modelled as a cantilever nonlinear beam, while the strut is represented as a linear spring connecting the wing to the fuselage. The analysis explores the impact of strut spanwise location, chordwise offset, and strut stiffness on flutter and post-instability behaviour.