Nonlinear aeroelastic scaling of high aspect-ratio wings

Abstract

The aeronautical industry is currently facing the simultaneous and conflicting demand to enhance flight efficiency while reducing emissions. One potential solution for reducing fuel consumption is to increase the wing aspect-ratio as it improves the lift-to-drag ratio. However, higher aspect-ratio wings result in higher deflections which in turn may lead to nonlinear aeroelastic behavior. In this work, the aeroelastic behavior of a conventional regional aircraft with high aspect-ratio wings is investigated. Aeroelastically scaled models using different scaling methodologies have been evaluated and compared. These methodologies use scaling factors derived from the governing aeroelastic equations of motion to set the target values to be matched through the optimization of the scaled model structure. Two linear scaling approaches were used: the first method consists of a direct modal response matching; while the second method uncouples the mass and stiffness distribution to achieve the modal response. An alternative nonlinear aeroelastic scaling methodology using equivalent static loads is presented, which uses two different optimization routines to match the nonlinear static response and the mode shapes of the full model. The aeroelastic response agreement was found to be considerably better when the nonlinear approach is applied and the accuracy is noticeably better than the results obtained using the traditional linear scaling methods.