Construction of a Morphing Wing Rib Actuated by a NiTi Wire

The incessant quest for more efficient aircraft has driven research into the development of aircraft with morphing wings. This concept aims to increase the flight efficiency of the aircraft by adapting the wing to the present air flow condition. This technology still has some limitations, among them the control mechanism of the shape adaptation mechanism. Some researchers have proposed the application of intelligent materials as alternative to conventional drive systems. Particularly shape memory alloys (SMAs) have been investigated due to their ability to recover large deformations if subjected to a suitable temperature (simple drive mechanism by Joule heating). This work presents a thermomechanical characterization of NiTi SMA micro-springs for application in morphing wings. The actuators work in a regime where the shape memory effect is created by heating of the stress-induced martensite phase, a phenomenon little explored in the literature. An adaptive wing prototype was constructed; the variation in camber deflection is the response of actuator heating by the Joule effect. A 3D wing prototype was tested in a wind tunnel under different air flows, showing the suitability of the actuators for this application. Next, the behavior of these spring actuators when subjected to force and strain under realistic conditions is discussed based on the phase transformation temperatures and the actuator response to heating. These results are fundamental for choosing the actuator size for a particular application and for the parameterization of controllers.

Section: Prototype Drive Testssupporting

confidence: 87%

Characterization of shape memory alloy micro-springs for application in morphing wings

Emiliavaca

Araújo

Souto

et al. 2018

“…For instance, Strelec et al [15] used SMA wires to change the airfoil profiles using Joule heating as input. Alameida et al [16] developed a morphing wing rib actuated by SMA wires. Sofia et al [17] developed a concept wing that uses SMA wires as a part of a bio-inspired vertebrate structure.…”

Section: Introductionmentioning

confidence: 99%

Modeling of integrated shape memory alloy and Macro-Fiber Composite actuated trailing edge

Mukherjee¹,

Ali²,

Arockiarajan³

2020

Owing to their high energy densities, smart materials like shape memory alloys (SMAs), Macro-Fiber Composites (MFCs) and, electroactive polymers (EAPs) have massive potential as actuators in wing morphing applications. In this article, a detailed numerical model is developed for the shape prediction of an elastic base that is actuated by a combination of a shape memory alloy (SMA) wire and a Macro-Fiber Composite (MFC) bimorph. It has been demonstrated using the model that it is possible to achieve large deflections at low frequencies by virtue of the phase transformations in the SMA wire and rapid actuation with small deflections due to the MFC bimorph. In the developed scheme, the elastic base is modeled using non-linear Euler-Bernoulli beam theory. The influence of the non-linear hysteresis in the SMA wire and the linear actuation characteristics of the MFC is studied by incorporating thermo-mechanical and electro-mechanical constitutive behavior into the non-linear beam theory. The system of coupled equations hence obtained, is solved iteratively to obtain the deflected shape of the elastic base. The results from the developed numerical scheme are validated against the previously available studies in the literature and experiments. Additionally, the synergistic advantage of using the two actuators together has been shown through experiments. As an illustration, a smart trailing edge camber morphing concept is developed by integrating the flexible elastic structure along with the two smart actuators to a NACA 0012 airfoil as the trailing edge.

“…In this paper, a new, fiber-optic interferometric technique capable of accurate and precise measurement of the deflection of the aircraft's morphing wing is presented. The guiding conditions for definition of the maximum deflection magnitude of ±5°and required accuracy of 0.1°come from the initial technical demands and aerodynamic analysis of morphing wing airfoil, carried out from the literature [18].…”

Section: Introductionmentioning

confidence: 99%

Measurement of morphing wing deflection by a cross-coherence fiber optic interferometric technique

Tomić

Djinovic

Scheerer

et al. 2017

A fiber-optic interferometric technique aimed at measuring the deflection of aircrafts' morphing wings is presented. The wing deflection induces a strain in the sensing fiber optic coils that are firmly fixed onto the wing. A change of the phase angle of the light propagating through the fiber is measured by an 'all-in-fiber' Michelson interferometer based on a 3×3 fiber-optic coupler. Two light sources of different coherence lengths and wavelengths are simultaneously used to ensure a wide measurement range and high accuracy. A new technique for determination of the zero deflection point using the cross-correlation of the two interferograms is proposed. The experiments performed on a specimen made of a carbon-fiber-reinforced plastic honeycomb structure demonstrated a relative uncertainty <1% and a precision of about 0.06°in the measuring range ±5°of the morphing wing deflection.