Morphing is an attractive option to reduce drag and improve the flow quality over the surface of a wing. These smooth changes can be brought about either globally on the whole wing or partly over a control surface. For a rotorcraft, this brings the opportunity to change the conventional flap with a flap that can morph. Consequently, not only the flow quality is improved but also the purpose to reduce the blade vortex interaction, causing otherwise strong noise and vibrations, is served. Besides, a morphing flap may help in reducing the overall weight of the rotorcraft by eliminating heavy mechanical links. However, although researchers have worked on numerous concepts, yet many of those did not make it to the prototype development and testing. This trend diminishes further for helicopters owing to the additional complexities.The present paper discusses the development and testing of a morphing concept called TRIC (TRanslation Induced Camber) where a morphing flap is actuated actively employing piezoelectric actuators and subjected to centrifugal loads. These actuators are selected based on the compact size and high actuation frequencies required for active control (1/rev) or to mitigate noise and vibrations (2/rev and higher). Twist can also be induced by applying differential camber of the morphing section span. The concept investigated relies on utilizing conventional aircraft structures and materials for morphing purposes; thus, in essence, has the potential to fulfil the conflicting requirements of lightweight, flexibility, and strength at the same time.As a case study, a small portion of the rotor flap is developed and tested under centrifugal loads. The design constraints and requirements are taken from the Bo105 helicopter to address the practical aspects of the implementation during design and development. The response of the morphing skin, which is made out of prepreg composite, and actuators is noted and compared to the numerical studies.The research work is a part of the European Union project SABRE (Shape Adaptive Blade for Rotorcraft Efficiency) under Horizon2020.

DEVELOPMENT AND TESTING OF AN ACTIVE TRAILING EDGE MORPHING DEMONSTRATOR FOR A ROTARY WING

Paper Proceedings: https://asmedigitalcollection.asme.org/SMASIS/SMASIS2021/volume/85499

ASME 2021 Smart Materials, Adaptive Structures and Intelligent Systems (SMASIS2021)

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