Student : Christopher Lupp
Sponsor : Air Force Research Laboratory (AFRL)
Summary:
The recent increase in flexibility of aircraft poses a challenge regarding aeroelastic stability. These aircraft designs feature higher aspect ratios for increased aerodynamic performance while employing new materials resulting in lighter wings that encounter geometrically nonlinear deformations. The increase in flexibility necessitates efficient analysis capabilities during the design process and the implementation of flutter constraints. While linear flutter constraints have been applied to multidisciplinary design optimizations, (gradient-based) constraints including geometrical nonlinearities have yet to be implemented.
In the course of this project the University of Michigan’s Nonlinear Aeroelastic Simulation Toolbox (UM/NAST) is being extended to determine sensitivities using an adjoint approach. The approach to determining gradients within UM/NAST applies to the entire code and permits the determination of sensitivities with respect to any variable available within the UM/NAST. Finally, a flutter constraint including geometrical nonlinearities is being formulated using the gradients from UM/NAST.