Investigation of multibody flight dynamic modes of an aircraft with flexible folding wing tips

ifasd2024 Tracking Number 61

It is always tempting to improve the aerodynamic efficiency of an aircraft by increasing the aspect ratio of its wings. However, there are mainly two issues: first regarding the size to meet airport gate limitations, and second the increased structural weight to make the wing resilient enough to the extra aerodynamic load produced by an increment in the aspect ratio of the wing. To address these issues, the semi-aeroelastic hinge concept has been recently proposed and it has attracted the attention of many researchers. Unlike conventional folding wing tips, as used on the 777-X, previous studies [1, 2] demonstrated that the use of semi-aeroelastic hinge devices in aircraft incorporating high-aspect-ratio wings allows not only to fit the vehicle into airport gates but also to alleviate aerodynamic loads by enabling floating wing tips to be used in-flight. This work is part recent effort led by Airbus in the frame of the Out of cycle NExt generation highly efficient air transport (ONEheart) project [3] and “we”, as a research group at the University of Southampton develop technology bricks to enable overall aircraft design. In this study, we investigate how flight modes and handling qualities of the vehicle are affected by the added flexibility to the wing. A representative civil jet aircraft with articulated wings is used to explore the effect of introducing a wing-tip device, connected to the wings with an elastic hinge, on the flight dynamic modes of the vehicle. Using a multibody dynamic simulation, an aircraft with articulated wings has been mathematically modeled, with the aircraft being composed of three rigid parts. This multibody formulation enables one to account for finite rotations of rigid folding wing tips in addition to the traditional flight dynamic modes. For sufficiently soft discrete structural hinges, substantial coupling between flexible and rigid modes occurs, leading to the potential to modify the flight dynamic behavior through structural flexibility. Using a multibody flight dynamics simulation tool with a nonlinear quasi-steady aerodynamic representation, different structural-hinge elastic properties, orientation, wing tip weight, and location on the aircraft are examined. It is also desirable to evaluate the transient and steady-state behavior of forces and moments that act as a constraint at hinges. In this regard, the time history of the constraint forces and moments on the hinge in different flight regimes have been also evaluated. The orientations of the hinges are symmetric to the x-z plane of the aircraft. However, sideslip can easily cause an asymmetry in the hinge orientation which may have an important effect on the flight dynamic response of the vehicle, therefore one of our primary goals in this study is to investigate the side-slip effect.