Design, Manufacture and Wind Tunnel Test of a Modular FishBAC Wing with Novel 3D Printed Skins

Abstract

This paper introduces a new modular Fish Bone Active Camber morphing wing with novel 3D printed skin panels. These skin panels are printed using two different Thermoplastic Polyurethane (TPU) formulations: a soft, high strain formulation for the deformable membrane of the skin, reinforced with a stiffer formulation for the stringers and mounting tabs. Additionally, this is the first FishBAC device designed to be modular in its installation and actuation. Therefore, all components can be removed and replaced for maintenance purposes without having to remove or disassemble other parts. A 1m span, 0.27m chord morphing wing with a 25% chord FishBAC was built and tested mechanically and in a low-speed wind tunnel. Results show that the new design is capable of achieving the same large changes in airfoil lift coefficient (approximate ΔCL≈0.55) with a low drag penalty seen in previous FishBAC work, but with a much simpler, practical and modular design. Additionally, the device shows a change in the pitching moment coefficient of ΔCM≈0.1, which shows the potential that the FishBAC has as a control surface.

Manufacturing and characterisation of 3D printed thermoplastic morphing skins

“…Panel 3 was tested too much larger stretch ratios to explore the failure mechanisms. The first drop in force was detected at λ = 2.75 and a load of 359.4 N, where the two panel This corresponds with the finding of these authors where a skin sheet printed onto Armadillo tabs was taken to failure, and no separation was detected [7]. Panel 2 was taken to a stretch ratio of λ = 1.8, at which permanent deformation was expected.…”

“…The similar chemical formulations of the two TPUs allow for creating a strong bond during printing through thermoplastic fusion without using adhesives. This 3D printing strategy has already been successfully implemented by these authors in printing stringers and mounting tabs from a stiff TPU formulation onto a softer phase membrane for a FishBAC morphing skin [7].…”

“…Specifically, the in-plane and out-of-plane stiffnesses will be measured as these are the two primary loading conditions of interest for morphing skins. This work also focuses on developing and improving an accurate, reliable and repeatable printing process that these authors introduced in Rivero et al [7] will underpin all future work on the concept. This paper is organised into three sections: first, the panel design approach and its constraints are discussed along with the manufacturing process.…”

A Multiaxial Fracture of Ecoflex Skin with Different Shore Hardness for Morphing Wing Application

“…With the exponential growth of the aviation industry in recent times, it is imperative to curtail greenhouse gas emissions [ 1 , 2 ]. As a result, novel technologies are being implemented, including lightweight structures, improved aerodynamics, and enhanced propulsion efficiency, to minimize fuel usage [ 3 , 4 , 5 ].…”

Multiaxial Deformations of Elastomeric Skins for Morphing Wing Applications: Theoretical Modeling and Experimental Investigations

“…They named it Geometrically Anisotropic ThermOplastic Rubber (GATOR), and a detailed analytical optimization study proved that the skin is better suited for low in-plane and high out-of-plane stiffness. In another work from the same group, Rivero et al [21] designed a modular FishBAC wing with 3D-printed skins. Uniaxial stress-strain curves are plotted to understand the nonlinear mechanical behavior of the skin.…”