Twistable morphing spar by double cylinder consisting of open and closed section members

Abstract

A new concept of twistable morphing spar is proposed to achieve an objective distribution of the twist angle more arbitrary and validity of the proposed design method is confirmed through experiments and numerical simulations using finite element analyses. A key aspect of the proposed twistable morphing spar concept is a double cylinder consisting of two cylinders, which is employed as a spar of twistable morphing wing. The ends of these cylinders are connected to each other at the tip side. One cylinder (Inner-cylinder) is a thick closed-section member. It carries torsion moments and connected to motor that provides moment to the member at the root side. The other cylinder (Outer-cylinder) is a variable-shape member composed of open and closed-sections. It is designed to achieve an objective distribution of twist angles, and is connected to the aircraft fuselage at the root side. The objective distribution of the twist angle can be achieved by designing the parameter we selected appropriate. In accordance with the design method, we manufactured an experimental model using a 3D printer and twist experiment was carried out. From comparison of the experimental results and the numerical simulation, feasibility of the twistable morphing spar and the validity of the design method were confirmed.