Topology Optimization & Experimental Validation of 0-υ Honeycomb for Adaptive Morphing Wing

Abstract

The application of a 0-υ honeycomb is demonstrated to allow the feasible and adaptive camber and chord changes of a wing. Substituting some of the original wing skin for this honeycomb, with equivalent out-of-plane flexural stiffness properties, and applying actuated loads along the chorddirection allows for independent changes in upper and lower skin area. This addition enables a continuous global camber and chord changes that can be varied locally along the span, removing the need for conventional flaps and ailerons. The removal of structural discontinuities, inherent with conventional control surfaces, when changing camber and chord has major aerodynamic advantages. Unlike many other wing morphing concepts, this setup is simple to implement and does not require significant changes in the current aircraft manufacturing paradigms to be adopted. This paper extends previous work, where the aerodynamic gains and aeroelastic feasibility of the morphing concept have been demonstrated, through topology optimization and experimental validation of the 0-υ honeycomb global properties used for morphing. The advent of additive layer manufacturing has allowed for economically feasible generation of complex honeycomb structures. Taking advantage of this, opening honeycomb cell wall thickness and shape as variables allows for the development of a 0-υ honeycomb that for a given out-ofplane flexural stiffness requires half the in-plane loading to morph compared to previous equivalent honeycomb structures. This development is expected to reduce the size of actuators required, and the energy used in morphing through the use of auxetic honeycombs.