Aeroelasticity of Telescopic Morphing UAV Wing

Abstract

Morphing wing technologies can improve aircraft efficiency by manipulating the geometry of the wings. The telescopic morphing wing (TMW) is one of the most promising morphing concepts. However, the modeling and analysis of these morphing mechanisms are highly challenging. The current work aims to model and study the morphing-induced dynamics on the aeroelastic response of a telescopic morphing wing. A coupled double cantilever beam model is developed for TMW. It consists of a primary host beam which is fixed at one end. A secondary sliding beam is considered to extend or retract (i.e., morph) in and out of the host beam. Quasi-steady aerodynamic theory is used to estimate the aerodynamic loads. Numerical results shows that the response of TMW increases significantly with increase in free stream velocity of air. The morphing process induces large deflections in the TMW. The span morphing consists of two processes; the span extension and the span retraction process. The oscillatory response during the extension process is observed to be aperiodic, which gradually converts into quasi-periodic response. In the post-extension, the TMW again starts to oscillate, which gradually decays down to a steady state response due to the aerodynamic damping. But for free-stream velocity in close vicinity of the flutter speed, oscillatory phase in post morphing process is almost insignificant. A preliminary study is done to analyse the effect of morphing speed on the aeroelastic response of TMW. It is observed for slow morphing speed, the aperiodic response during morphing process converts into quasi-periodic response very early. For high morphing speed, the response remains aperiodic throughout the morphing process. Even in post morphing process the oscillatory phase sustains for a longer time period for higher morphing speed.