Morphing Wing Aeroelasticity by Continuous Dynamic Simulation using Nonlinear Aerodynamic/Nonlinear Structure Interaction (NANSI) Methodology*

Our objective is to develop a nonlinear aerodynamic and nonlinear structural interaction (NANSI) methodology as an expedient aeroelastic tool to handle continuous dynamic motion of morphing vehicles/wings throughout the flight regimes of subsonic to transonic speeds. The proposed morph vehicles for method demonstration is the Lockheed Folding wing (the Folding wing). Preliminary results on Flutter/LCO of the Folding wing in continuous morph are presented. The developmental procedures of the tools needed for NANSI are presented in three sections. Section 2.0 describes the development of a nonlinear structural reduced order modeling (ROM) and morphing dynamics in terms of sub-structural formulation for the Folding wing. Section 3.0 presents the results of direct, or full-order, aeroelastic solutions in terms of flutter/LCO for the Folding wing in quasi-steady morph motion and in continuous dynamic morph motions. A CartEULER unsteady aerodynamic solver is used as an expedient, userfriendly tool for aeroelastic applications. Section 4.0 presents the establishment of aerodynamic ROM methodology based on a system identification strategy, with which an aeroelastic ROM-ROM methodology has been successfully developed. In terms of flutter/LCO solutions of the Folding wing, a selected example shows that ROM-ROM dramatically reduces the computing time by two orders of magnitude as opposed to that required by the direct method.