Active Aeroelastic Tailoring of High-Aspect-Ratio Composite Wings.

摘要

Nonlinear aeroelastic modeling and the fundamental mechanisms of active aeroelastic tailoring of high-aspect-ratio composite wings for High- altitude Long-endurance (HALE) aircraft is presented. To investigate the effects of distributed anisotropic strain actuation and their synergism with the passive aeroelastic tailored composite structure, a new framework was developed for analysis and design of high aspect ratio active flexible wings. The formulation is capable of modeling the nonlinear large deflection behavior of slender wings and other structural members, deformation due to applied voltages on the active plies in the skin of the wing, and the unsteady subsonic aerodynamic forces acting on the wing. Because HALE wings are long and slender, they can be well modeled as beams undergoing three dimensional displacements and rotations. The cross sectional stiffness, inertia, and actuation properties of the wing are calculated along the span, and then a nonlinear beam model is constructed. A novel beam representation was developed and it was based entirely on the beam strains, resulting in a computationally efficient low- order model suitable for preliminary structural design and control synthesis. The formulation was then extended to analyze different beam configurations, particularly in the presence of joints and splits. With that, the entire vehicle can be modeled and non- conventional wing configurations such as the joined wing could be analyzed. Finally, different aircraft configurations such as the ones being considered for the new Air Force Sensor Craft vehicle were studied.