Geometrically Nonlinear Aeroelastic Scaling for Very Flexible Aircraft

Abstract

High-aspect-ratio wings present in very flexible aircraft can undergo large deformations, which results in significant changes in natural frequencies as well as in static and dynamic aeroelastic response. This geometric nonlinear behavior becomes an integral part of any aeroelastic analysis to be conducted in such class of vehicles. Aeroelastic scaling is an important way to study the aeroelastic behavior of aircraft, and it is an integral part in risk mitigation for aircraft development. However, the current aeroelastic scaling methodologies have focused on geometrically linear structures. This paper demonstrates a methodology for geometrically nonlinear aeroelastic scaling of very flexible aircraft. The known linear scaling factors and similarity rules are extended to address geometrically nonlinear aeroelastic scaling. A high-aspect-ratio flying wing in free flight is taken as an example to verify the new scaling procedure, and numerical studies are conducted using the University of Michigan’s Nonlinear Aeroelastic Simulation Toolbox. Numerical results support the new approach for aeroelastic scaling of very flexible aircraft.