Flutter of Telescopic Span Morphing Wings

Abstract

This paper studies the aeroelastic behavior of telescopic, multi-segment, span morphing wings. The wing is modeled as a linear, multi-segment, stepped, cantilever Euler–Bernoulli beam. It consists of three segments along the axis and each segment has different geometric, mechanical, and inertial properties. The aeroelastic analysis takes into account spanwise out-of-plane bending and torsion only, for which the corresponding shape functions are derived and validated. The use of shape functions allows representing the wing as an equivalent aerofoil whose generalized coordinates are defined at the wingtip according to the Rayleigh–Ritz method. Theodorsen’s unsteady aerodynamic theory is used to estimate the aerodynamic loads. A representative Padé approximation for the Theodorsen’s transfer function is utilized to model the aerodynamic behaviors in state-space form allowing time-domain simulation and analysis. The effect of the segments’ mechanical, geometric, and inertial properties on the aeroelastic behavior of the wing is assessed. Finally, the viability of span morphing as a flutter suppression device is studied.