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19 pages, 15693 KiB

Open AccessArticle

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

by Andrés E. Rivero, Stephane Fournier, Rafael M. Heeb and Benjamin K. S. Woods

Appl. Sci. 2022, 12(2), 652; https://doi.org/10.3390/app12020652 - 10 Jan 2022

Cited by 12 | Viewed by 3205

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 [...] Read more.

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 1 m span, 0.27 m 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

Δ C_{L} \approx 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

Δ C_{M} \approx 0.1

, which shows the potential that the FishBAC has as a control surface. Full article

(This article belongs to the Special Issue Smart Aircraft Morphing Technologies)

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17 pages, 2661 KiB

Open AccessArticle

Experimental Validation and Evaluation of a Coupled Twist-Camber Morphing Wing Concept

by José Lobo do Vale, John Raffaelli and Afzal Suleman

Appl. Sci. 2021, 11(22), 10631; https://doi.org/10.3390/app112210631 - 11 Nov 2021

Cited by 4 | Viewed by 2335

Abstract

A morphing wing concept allowing for coupled twist-camber shape adaptation is proposed. The design is based on an optimized thickness distribution both spanwise and chordwise to be able to morph the wing sections into targeted airfoil shapes. Simultaneously, the spanwise twist is affected [...] Read more.

A morphing wing concept allowing for coupled twist-camber shape adaptation is proposed. The design is based on an optimized thickness distribution both spanwise and chordwise to be able to morph the wing sections into targeted airfoil shapes. Simultaneously, the spanwise twist is affected by the actuation. The concept provides a higher degree of control on the lift distribution which can be used for roll control, drag minimization, and active load alleviation. Static deformation and flight tests have been performed to evaluate and quantify the performance of the proposed mechanism. The ground tests include mapped actuated wing shapes, and wing mass and actuation power requirements. Roll authority, load alleviation, and aerodynamic efficiency estimates for different configurations were calculated using a lifting line theory coupled with viscous 2D airfoil data. Roll authority was estimated to be low when compared to a general aviation aircraft while the load alleviation capability was found to be high. Differences between the lift to drag ratio between the reference and morphing wing configurations are considerable. Mass and actuation energy present challenges that can be mitigated. The flight tests were used to qualitatively assess the roll control capability of the prototype, which was found to be adequate. Full article

(This article belongs to the Special Issue Smart Aircraft Morphing Technologies)

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17 pages, 26023 KiB

Open AccessArticle

Design of a Variable-Stiffness Compliant Skin for a Morphing Leading Edge

by Zhigang Wang and Yu Yang

Appl. Sci. 2021, 11(7), 3165; https://doi.org/10.3390/app11073165 - 2 Apr 2021

Cited by 10 | Viewed by 2608

Abstract

A seamless and smooth morphing leading edge has remarkable potential for noise abatement and drag reduction of civil aircraft. Variable-stiffness compliant skin based on tailored composite laminate is a concept with great potential for morphing leading edge, but the currently proposed methods have [...] Read more.

A seamless and smooth morphing leading edge has remarkable potential for noise abatement and drag reduction of civil aircraft. Variable-stiffness compliant skin based on tailored composite laminate is a concept with great potential for morphing leading edge, but the currently proposed methods have difficulty in taking the manufacturing constraints or layup sequence into account during the optimization process. This paper proposes an innovative two-step design method for a variable-stiffness compliant skin of a morphing leading edge, which includes layup optimization and layup adjustment. The combination of these two steps can not only improve the deformation accuracy of the final profile of the compliant skin but also easily and effectively determine the layup sequence of the composite layup. With the design framework, an optimization model is created for a variable-stiffness compliant skin, and an adjustment method for its layups is presented. Finally, the deformed profiles between the directly optimized layups and the adjusted ones are compared to verify its morphing ability and accuracy. The final results demonstrate that the obtained deforming ability and accuracy are suitable for a large-scale aircraft wing. Full article

(This article belongs to the Special Issue Smart Aircraft Morphing Technologies)

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28 pages, 13610 KiB

Open AccessArticle

Analysis and Design of a Leading Edge with Morphing Capabilities for the Wing of a Regional Aircraft—Gapless Chord- and Camber-Increase for High-Lift Performance

by Conchin Contell Asins, Volker Landersheim, Dominik Laveuve, Seiji Adachi, Michael May, Jens-David Wacker and Julia Decker

Appl. Sci. 2021, 11(6), 2752; https://doi.org/10.3390/app11062752 - 19 Mar 2021

Cited by 8 | Viewed by 4212

Abstract

In order to contribute to achieving noise and emission reduction goals, Fraunhofer and Airbus deal with the development of a morphing leading edge (MLE) as a high lift device for aircraft. Within the European research program “Clean Sky 2”, a morphing leading edge [...] Read more.

In order to contribute to achieving noise and emission reduction goals, Fraunhofer and Airbus deal with the development of a morphing leading edge (MLE) as a high lift device for aircraft. Within the European research program “Clean Sky 2”, a morphing leading edge with gapless chord- and camber-increase for high-lift performance was developed. The MLE is able to morph into two different aerofoils—one for cruise and one for take-off/landing, the latter increasing lift and stall angle over the former. The shape flexibility is realised by a carbon fibre reinforced plastic (CFRP) skin optimised for bending and a sliding contact at the bottom. The material is selected in terms of type, thickness, and lay-up including ply-wise fibre orientation based on numerical simulation and material tests. The MLE is driven by an internal electromechanical actuation system. Load introduction into the skin is realised by span-wise stringers, which require specific stiffness and thermal expansion properties for this task. To avoid the penetration of a bird into the front spar of the wing in case of bird strike, a bird strike protection structure is proposed and analysed. In this paper, the designed MLE including aerodynamic properties, composite skin structure, actuation system, and bird strike behaviour is described and analysed. Full article

(This article belongs to the Special Issue Smart Aircraft Morphing Technologies)

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27 pages, 31615 KiB

Open AccessArticle

Integrated Design of a Morphing Winglet for Active Load Control and Alleviation of Turboprop Regional Aircraft

by Ignazio Dimino, Giovanni Andreutti, Frédéric Moens, Federico Fonte, Rosario Pecora and Antonio Concilio

Appl. Sci. 2021, 11(5), 2439; https://doi.org/10.3390/app11052439 - 9 Mar 2021

Cited by 27 | Viewed by 5428

Abstract

Aircraft winglets are well-established devices that improve aircraft fuel efficiency by enabling a higher lift over drag ratios and lower induced drag. Retrofitting winglets to existing aircraft also increases aircraft payload/range by the same order of the fuel burn savings, although the additional [...] Read more.

Aircraft winglets are well-established devices that improve aircraft fuel efficiency by enabling a higher lift over drag ratios and lower induced drag. Retrofitting winglets to existing aircraft also increases aircraft payload/range by the same order of the fuel burn savings, although the additional loads and moments imparted to the wing may impact structural interfaces, adding more weight to the wing. Winglet installation on aircraft wing influences numerous design parameters and requires a proper balance between aerodynamics and weight efficiency. Advanced dynamic aeroelastic analyses of the wing/winglet structure are also crucial for this assessment. Within the scope of the Clean Sky 2 REG IADP Airgreen 2 project, targeting novel technologies for next-generation regional aircraft, this paper deals with the integrated design of a full-scale morphing winglet for the purpose of improving aircraft aerodynamic efficiency in off-design flight conditions, lowering wing-bending moments due to maneuvers and increasing aircraft flight stability through morphing technology. A fault-tolerant morphing winglet architecture, based on two independent and asynchronous control surfaces with variable camber and differential settings, is presented. The system is designed to face different flight situations by a proper action on the movable control tabs. The potential for reducing wing and winglet loads by means of the winglet control surfaces is numerically assessed, along with the expected aerodynamic performance and the actuation systems’ integration in the winglet surface geometry. Such a device was designed by CIRA for regional aircraft installation, whereas the aerodynamic benefits and performance were estimated by ONERA on the natural laminar flow wing. An active load controller was developed by PoliMI and UniNA performed aeroelastic trade-offs and flutter calculations due to the coupling of winglet movable harmonics and aircraft wing bending and torsion. Full article

(This article belongs to the Special Issue Smart Aircraft Morphing Technologies)

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24 pages, 8572 KiB

Open AccessArticle

Gradient-Based Aerodynamic Optimization of an Airfoil with Morphing Leading and Trailing Edges

by Zhenkai Zhang, Alessandro De Gaspari, Sergio Ricci, Chen Song and Chao Yang

Appl. Sci. 2021, 11(4), 1929; https://doi.org/10.3390/app11041929 - 22 Feb 2021

Cited by 11 | Viewed by 3371

Abstract

This article presents a gradient-based aerodynamic optimization framework and investigates optimum deformations for a transonic airfoil equipped with morphing leading and trailing edges. Specifically, the proposed optimization framework integrates an innovative morphing shape parameterization with a high fidelity Reynolds-averaged Navier–Stokes computational fluid dynamic [...] Read more.

This article presents a gradient-based aerodynamic optimization framework and investigates optimum deformations for a transonic airfoil equipped with morphing leading and trailing edges. Specifically, the proposed optimization framework integrates an innovative morphing shape parameterization with a high fidelity Reynolds-averaged Navier–Stokes computational fluid dynamic solver, a hybrid mesh deformation algorithm, and an efficient gradient evaluation method based on continuous adjoint implementation. To achieve a feasible morphing shape, some structural properties of skin and wing-box constraints were introduced into the morphing shape parameterization, which offers skin length control and enables wing-box shape invariance. In this study, the optimum leading and trailing edge deformations with minimization of drag at this cruise stage were searched for using the adjoint-based optimization with a nested feasible morphing procedure, subject to the wing-box, skin length, and airfoil volume constraints. The numerical studies verified the effectiveness of the optimization strategy, and demonstrated the significant aerodynamic performance improvement achieved by using the morphing devices. A lambda shock pattern was observed for the optimized morphing leading edge. That result further indicates the importance of leading edge radius control. Full article

(This article belongs to the Special Issue Smart Aircraft Morphing Technologies)

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29 pages, 13315 KiB

Open AccessArticle

Multiobjective Optimization for the Aero-Structural Design of Adaptive Compliant Wing Devices

by Alessandro De Gaspari

Appl. Sci. 2020, 10(18), 6380; https://doi.org/10.3390/app10186380 - 13 Sep 2020

Cited by 17 | Viewed by 3485

Abstract

The design of morphing structures must combine conflicting structural requirements and multiple load conditions that are related to the aerodynamic shapes aimed at optimizing aircraft performance. This article proposes a multilevel approach for the design of adaptive compliant wing devices. A set of [...] Read more.

The design of morphing structures must combine conflicting structural requirements and multiple load conditions that are related to the aerodynamic shapes aimed at optimizing aircraft performance. This article proposes a multilevel approach for the design of adaptive compliant wing devices. A set of aerodynamic shapes, and associated their loads, is defined by a shape optimization, coupled with a three-dimensional parametric technique, that can identify only feasible shape changes due to the morphing. A topology and sizing multiobjective optimization drives the Pareto-optimal structural design of the compliant structure, which is able to deform itself to match, once actuated, all of the previously defined aerodynamic shapes. Next two design levels produce a more detailed solution which is extended until the definition of the complete device. A 90 pax, twin prop green regional aircraft is used as an innovative aircraft demonstration platform for the design of the morphing droop nose to be installed on the wing. The results show the structural capabilities of this device in terms of the external shape quality and the strain requirements. This work enables the validation of the design method and prove the functionality of compliant structures when accounting for the aeroelastic effects due to the interaction with the wing-box. Full article

(This article belongs to the Special Issue Smart Aircraft Morphing Technologies)

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Review

Jump to: Research

24 pages, 5905 KiB

Open AccessReview

Review of Adaptive Shock Control Systems

by Sven Christian Künnecke, Srinivas Vasista, Johannes Riemenschneider, Ralf Keimer and Markus Kintscher

Appl. Sci. 2021, 11(2), 817; https://doi.org/10.3390/app11020817 - 16 Jan 2021

Cited by 11 | Viewed by 3564

Abstract

Drag reduction plays a major role in future aircraft design in order to lower emissions in aviation. In transonic flight, the transonic shock induces wave drag and thus increases the overall aircraft drag and hence emissions. In the past decades, shock control has [...] Read more.

Drag reduction plays a major role in future aircraft design in order to lower emissions in aviation. In transonic flight, the transonic shock induces wave drag and thus increases the overall aircraft drag and hence emissions. In the past decades, shock control has been investigated intensively from an aerodynamic point of view and has proven its efficacy in terms of reducing wave drag. Furthermore, a number of concepts for shock control bumps (SCBs) that can adapt their position and height have been introduced. The implementation of adaptive SCBs requires a trade-off between aerodynamic benefits, system complexity and overall robustness. The challenge is to find a system with low complexity which still generates sufficient aerodynamic improvement to attain an overall system benefit. The objectives of this paper are to summarize adaptive concepts for shock control, and to evaluate and compare them in terms of their advantages and challenges of their system integrity so as to offer a basis for robust comparisons. The investigated concepts include different actuation systems as conventional spoiler actuators, shape memory alloys (SMAs) or pressurized elements. Near-term applications are seen for spoiler actuator concepts while highest controllability is identified for concepts several with smaller actuators such as SMAs. Full article

(This article belongs to the Special Issue Smart Aircraft Morphing Technologies)

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