Numerical Investigation of Autonomous Camber Morphing of a Helicopter Rotor Blade using Shape Memory Alloys

Design and development of modern air vehicles seeks to produce airborne structures that are able to fly in a wide range of operational conditions with increased fuel efficiency and reduced environmental impact. To be able to operate efficiently throughout the operational envelop these structures need to be able to adapt their aerodynamic characteris-tics, a process achievable through the introduction of morphing regions. In this study, a numerical investigation of an autonomous camber morphing helicopter blade is presented considering Shape Memory Alloy materials able to un-dergo the Two-Way Shape Memory Effect. A series of designs and respective finite element analyses is employed to identify the effect of various parameters on various configurations that include the number of intermediate spars, the extend of the morphing section along the blade and the boundary condition between the pristine and the morphing portion. Overall, eliminating the need for pre-stress of the SMA component before being embedded in the host struc-ture leads in significant reduction of the maximum strain and stress developed on the upper skin (passive component).