Nonlinear Aeroelasticity of a Very Flexible Blended-Wing-Body Aircraft

摘要

This paper presents a study on the coupled aeroelastic/flight dynamic stability and gust response of a blended-nwing-body aircraft that derives from the U.S. Air Force’s High Lift-Over-Drag Active (HiLDA) wing experimentalnmodel. An effective method is used to model very flexible blended-wing-body vehicles based on a low-ordernaeroelastic formulation that is capable of capturing the important structural nonlinear effects and couplingswith thenflight dynamic degrees of freedom. A nonlinear strain-based beam finite element formulation is used. Finite statenunsteady subsonic aerodynamic loads are coupled to all lifting surfaces, including the flexible body. Based on thenproposed model, aeroelastic stability is studied and compared with the flutter results with all or partial rigid-bodyndegrees of freedom constrained. The applicability of wind-tunnel aeroelastic results (where the rigid-body motion isnlimited) is discussed in view of the free-flight conditions (with all 6 rigid-body degrees of freedom). Furthermore,neffects of structural and aerodynamic nonlinearities as well as wing bending/torsion rigidity coupling on the aircraftncharacteristics are also discussed in this paper.