Aeroelastic wave propagation in mechanical metamaterial wing under unsteady aerodynamics

This work proposes a novel UAV metamaterial wing with periodically placed mechanical resonators (MR) to attenuate the coupled flexural-torsional (FT) waves under unsteady aerodynamic loads. An aeroelastic transfer matrix incorporating unsteady aerodynamics is developed for wave propagation analysis. The bandgap characteristics for coupled FT waves under quasi-steady and unsteady aerodynamics are analyzed and compared. Additionally, the effect of chordwise resonator placement on bandgap characteristics is investigated. The results indicate that the metamaterial wing interacting with aerodynamic loads forms a new aeroelastic bandgap along with the local (MR) bandgap. The aerodynamic effects significantly influence the bandgap for torsional waves. Comparing the quasi-steady and unsteady aerodynamic conditions, torsional bandgap attenuation is higher for quasi-steady aerodynamics. However, unsteady aerodynamics reduces MR bandgap performance and introduces triple peaks in the aeroelastic bandgap. Further, placing resonators near the trailing edge of the wing enhances the wave attenuation across a broader frequency range. The study also examines the effect of airspeed variations on the bandgap characteristics. These results highlight the potential of MR-based metamaterial wings for effectively attenuating both flexural and torsional waves under unsteady aerodynamics and providing valuable insights for UAVs operating in turbulent wind conditions.