Christopher A. Lupp, Carlos E.S. Cesnik, Philip Beran, Joshua Deaton, David Easterling
DOI Number: N/A
Conference number: IFASD-2019-069
Higher aspect ratio, more flexible wings pose an aeroelastic design challenge for future aircraft. These vehicles may encounter geometrically nonlinear effects and/or participa- tion of rigid body degrees of freedom in their flutter modes. If geometrically nonlinear flutter analyses are not included during the design process, the final configuration obtained may be infeasible. This paper presents the inclusion of a beam-based nonlinear flutter constraint in a multi-fidelity aircraft optimization framework in which the objective function is evaluated us- ing high-fidelity FEM simulations. The flutter constraint is applied to the entire flight envelope thereby ensuring a feasible design. The beam-based constraint is coupled with the high-fidelity optimization problem using an equivalent beam condensation process. The gradients of the condensation process are evaluated and verified. Finally, the assembled multi-fidelity problem is evaluated for the initial optimization iteration.