AEROELASTIC WAVE PROPAGATIONS OF METAMATERIAL UAV WING

Aeroelastic wave propagation characteristics of a UAV wing with locally resonant metamaterials are studied. The metamaterial wing is designed as a box-beam type structure with locally resonant resonators placed periodically, along the span, to create the metamaterial characteristics. An Aeroelastic Transfer Matrix method is developed based on the Transfer Matrix method for aeroelastic wave propagation analysis. Wave propagation analysis are performed with- and without aerodynamic effects. For a preliminary understanding, bending and torsional motions are assumed to be decoupled. The elastic wave propagation analysis, i.e. without aerodynamic loads, show the attenuation of flexural waves at low frequency ranges for the baseline wing and resonator properties. The unit cell length, resonator stiffness and mass shows significant impact on the band gaps of elastic flexural wave propagation. The effect aerodynamic damping on the flexural wave propagation of the wing, ie aeroelastic waves, is studied with the quasi-steady aerodynamic models. The aerodynamic damping, even without the resonator, introduces the stop band at a very low frequency range and its effect increases with the flow velocity. Further, the band gaps of elastic flexural waves due to the locally resonant resonator gets broadened due to its interaction with aerodynamic damping. Finally, aeroelastic wave propagation with coupled bending and torsion motions, and resonators are studied. Results show that the considerable band gaps can be formed for both the torsion and bending waves with resonators. Overall, this study shows that the effective design of UAV wing with metamaterials can significantly attenuate the aeroelastic vibrations.