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Aircraft Morphing Systems 2.0

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A special issue of Biomimetics (ISSN 2313-7673). This special issue belongs to the section "Bioinspired Sensorics, Information Processing and Control".

Deadline for manuscript submissions: closed (20 October 2022) | Viewed by 33001

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Special Issue Editors

Dr. Antonio Concilio

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Guest Editor

Department of Adaptive Structures, Centro Italiano Ricerche Aerospaziali, 81043 Capua, CE, Italy
Interests: adaptive structures; smart structures; morphing; structural health monitoring; integrated vehicle health monitoring; vibroacoustic control
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Dr. Salvatore Ameduri

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Guest Editor

CIRA, Italian Aerospace Research Centre, Via Maiorise, 81043 Capua, Italy
Interests: morphing wings; smart materials; noise and vibration control
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Dr. Ignazio Dimino

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Guest Editor

Adaptive Structures Tech Research Unit, CIRA, The Italian Aerospace Research Centre, 81043 Capua, CE, Italy
Interests: morphing technology; smart structures; active control; topology optimization
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Dr. Rosario Pecora

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Guest Editor

Department of Industrial Engineering—Aerospace Division, University of Naples “Federico II”, Via Claudio, 21, 80125 Napoli, NA, Italy
Interests: smart structures; smart aircraft technologies; morphing structures; structural dynamics; vibration control; dynamic aeroelasticity; non-linear dynamics; mechanics and experimental dynamics
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Special Issue Information

Dear Colleagues,

Following the wide interest for morphing systems on aircraft platforms, this topic has been considerably developing in recent years. This higher focus permitted us to highlight the principal showstoppers that currently inhibit this technology to be actually flown on-board of commercial aircraft. Largely implemented architectures, both kinematic or compliant, i.e., based on classical mechanical chain or targeted mechanical design, rely on commercial components, and therefore on assessed devices. It is therefore the assembly, the system in itself that shall include those setbacks. Complexity, weight penalty and room necessity will then be assessed at the level of subsystems or systems. In other words, it is the assembly that currently drives the technological challenge. Even in the case of specific technologies far from being assessed as commercial products, or at least as assessed realizations, integration aspects play a fundamental role in the final acceptance of the compete device. It is the case of skins, the components targeting to ensure a regular geometry to the morphing system, which shall guarantee the continuity between high strain levels, characteristic of morphing implementation, and ordinary deformation levels, typical of standard structural systems. This Special Issue aims at collecting papers that can provide a better hint on the current status of the system realization, targeting integration of the different components, and the interface with the main structural body. In this regard, articles on the following topics are mainly searched for:

Integrated structural systems
Kinematic architectures
Compliant architectures
Integrated morphing skins
Integrated actuator networks
Integrated sensor networks
Integrated control systems
FHA assessment
Aeroelastic issues
Performance
Ground testing of morphing systems
Fight testing of morphing systems
TRL

Dr. Antonio Concilio
Dr. Salvatore Ameduri
Dr. Ignazio Dimino
Dr. Rosario Pecora
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Biomimetics is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

morphing
adaptive structures
smart structures
kinematic systems
compliant systems
morphing skins
actuator networks
sensor networks
control systems
FHA
aeroelasticity
performance
experimental characterization
TRL

Published Papers (9 papers)

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Research

16 pages, 2844 KiB

Open AccessArticle

Smart Biomechanical Adaptation Revealed by the Structure of Ostrich Limb Bones

by Simone Conti, Giuseppe Sala and Octavio Mateus

Biomimetics 2023, 8(1), 98; https://doi.org/10.3390/biomimetics8010098 - 28 Feb 2023

Cited by 1 | Viewed by 4182

Abstract

Ostriches are known to be the fastest bipedal animal alive; to accomplish such an achievement, their anatomy evolved to sustain the stresses imposed by running at such velocities. Ostriches represent an excellent case study due to the fact that their locomotor kinematics have been extensively studied for their running capabilities. The shape and structure of ostrich bones are also known to be optimized to sustain the stresses imposed by the body mass and accelerations to which the bones are subjected during movements. This study focuses on the limb bones, investigating the structure of the bones as well as the material properties, and how both the structure and material evolved to maximise the performance while minimising the stresses applied to the bones themselves. The femoral shaft is hollowed and it presents an imbricate structure of fused bone ridges connected to the walls of the marrow cavity, while the tibial shaft is subdivided into regions having different mechanical characteristics. These adaptations indicate the optimization of both the structure and the material to bear the stresses. The regionalization of the material highlighted by the mechanical tests represents the capability of the bone to adapt to external stimuli during the life of an individual, optimizing not only the structure of the bone but the material itself. Full article

(This article belongs to the Special Issue Aircraft Morphing Systems 2.0)

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Figure 1

27 pages, 18976 KiB

Open AccessEditor’s ChoiceArticle

Flow Control around the UAS-S45 Pitching Airfoil Using a Dynamically Morphing Leading Edge (DMLE): A Numerical Study

by Musavir Bashir, Nicola Zonzini, Ruxandra Mihaela Botez, Alessandro Ceruti and Tony Wong

Biomimetics 2023, 8(1), 51; https://doi.org/10.3390/biomimetics8010051 - 26 Jan 2023

Cited by 2 | Viewed by 1662

Abstract

This paper investigates the effect of the Dynamically Morphing Leading Edge (DMLE) on the flow structure and the behavior of dynamic stall vortices around a pitching UAS-S45 airfoil with the objective of controlling the dynamic stall. An unsteady parametrization framework was developed to model the time-varying motion of the leading edge. This scheme was then integrated within the Ansys-Fluent numerical solver by developing a User-Defined-Function (UDF), with the aim to dynamically deflect the airfoil boundaries, and to control the dynamic mesh used to morph and to further adapt it. The dynamic and sliding mesh techniques were used to simulate the unsteady flow around the sinusoidally pitching UAS-S45 airfoil. While the

γ - R e_{θ}

turbulence model adequately captured the flow structures of dynamic airfoils associated with leading-edge vortex formations for a wide range of Reynolds numbers, two broader studies are here considered. Firstly, (i) an oscillating airfoil with the DMLE is investigated; the pitching-oscillation motion of an airfoil and its parameters are defined, such as the droop nose amplitude (

A_{D}

) and the pitch angle at which the leading-edge morphing starts (

M_{S T}

). The effects of the

A_{D}

and the

M_{S T}

on the aerodynamic performance was studied, and three different amplitude cases are considered. Secondly, (ii) the DMLE of an airfoil motion at stall angles of attack was investigated. In this case, the airfoil was set at stall angles of attack rather than oscillating it. This study will provide the transient lift and drag at different deflection frequencies of 0.5 Hz, 1 Hz, 2 Hz, 5 Hz, and 10 Hz. The results showed that the lift coefficient for the airfoil increased by 20.15%, while a 16.58% delay in the dynamic stall angle was obtained for an oscillating airfoil with DMLE with

A_{D}

= 0.01 and

M_{S T}

= 14.75°, as compared to the reference airfoil. Similarly, the lift coefficients for two other cases, where

A_{D}

= 0.05 and

A_{D}

= 0.0075, increased by 10.67% and 11.46%, respectively, compared to the reference airfoil. Furthermore, it was shown that the downward deflection of the leading edge increased the stall angle of attack and the nose-down pitching moment. Finally, it was concluded that the new radius of curvature of the DMLE airfoil minimized the streamwise adverse pressure gradient and prevented significant flow separation by delaying the Dynamic Stall Vortex (DSV) occurrence. Full article

(This article belongs to the Special Issue Aircraft Morphing Systems 2.0)

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Graphical abstract

16 pages, 1718 KiB

Open AccessArticle

Enhanced Range and Endurance Evaluation of a Camber Morphing Wing Aircraft

by Bruce W. Jo and Tuba Majid

Biomimetics 2023, 8(1), 34; https://doi.org/10.3390/biomimetics8010034 - 13 Jan 2023

Cited by 4 | Viewed by 2533

Abstract

Flight range, endurance, maneuverability, and agility are the key elements that determine an aircraft’s performance. Both conventional and morphing wing aircraft have been well studied and estimated in all aspects of performance. When considering the performance of morphing aircraft, most works address aspects [...] Read more.

L

and

D

as well as flight envelopes for flight dynamics and control perspectives. However, the actual benefits of adopting morphing technologies in practical aspects such as aircraft operation, mission planning, and sustainability have not been addressed so far. Thus, this paper addresses the practical aspect of the benefits when adopting a camber morphing wing aircraft. Identical geometrical and computational conditions were applied to an already-existing aircraft: the RQ-7a Shadow. The wing structure was switched between a fixed wing and a camber morphing wing to generate conventional and morphing wing geometries. The fixed-wing cases had varying flap deflection angles, and the camber morphing wing cases had varying camber rates from 4% to 8%. Once the

C_{L}

values of the fixed and morphing wing cases were matched up to two significant figures, the

C_{D}

and

C_{L} / C_{D}

were analyzed for these matching cases to calculate the flight endurance, range, and improvement. When NACA 6410 is adopted, a 17% improvement in flight range and endurance average was expected. In the case of NACA 8410, an average 60% improvement was expected. Full article

(This article belongs to the Special Issue Aircraft Morphing Systems 2.0)

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27 pages, 6467 KiB

Open AccessArticle

A Preliminary Technology Readiness Assessment of Morphing Technology Applied to Case Studies

by Marco Fabio Miceli, Salvatore Ameduri, Ignazio Dimino, Rosario Pecora and Antonio Concilio

Biomimetics 2023, 8(1), 24; https://doi.org/10.3390/biomimetics8010024 - 06 Jan 2023

Cited by 2 | Viewed by 1596

Abstract

In an innovative system, it is essential to keep under control the crucial development phases, which should consider several aspects involving, for instance, the modeling or the assessment of suitable analytical representations. Aiming to pursue a final demonstration to verify the actual capability of an engineering idea, however, some fundamental elements may have been partially considered. Many projects state the initial and final technology readiness level based on the famous scale introduced by the US National and Aeronautics Space Administration (NASA) many years ago and now widespread in many fields of technology innovation. Its nine-step definition provides a high-level indication of the maturity of the observed innovative system. Trivially, the resolution of that macroscopic meter is not made for catching advancement details, but it rather provides comprehensive information on the examined technology. It is, therefore, necessary to refer to more sophisticated analysis tools that can show a more accurate picture of the development stage and helps designers to highlight points that deserve further attention and deeper analysis. The risk is to perform a very good demonstration test that can miss generality and remain confined only to that specific experimental campaign. Moving on to these assumptions, the authors expose three realizations of theirs concerning aeronautic morphing systems, to the analysis of a well-assessed Technology Readiness Level instrument. The aim is to define the aspects to be further assessed, the aspect to be considered fully mature, and even aspects that could miss some elementary point to attain full maturation. Such studies are not so frequent in the literature, and the authors believe to give a valuable, yet preliminary, contribution to the engineering of breakthrough systems. Without losing generality, the paper refers to the 2.2 version of a tool set up by the US Air Force Research Laboratory (AFRL), and NASA, with the aim to standardize the evaluation process of the mentioned nine-step TRL. Full article

(This article belongs to the Special Issue Aircraft Morphing Systems 2.0)

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17 pages, 10554 KiB

Open AccessArticle

3D Zero Poisson’s Ratio Honeycomb Structure for Morphing Wing Applications

by Xiaobo Gong, Chengwei Ren, Jian Sun, Peiru Zhang, Lei Du and Fang Xie

Biomimetics 2022, 7(4), 198; https://doi.org/10.3390/biomimetics7040198 - 12 Nov 2022

Cited by 4 | Viewed by 1956

Abstract

Such as flying creatures, morphing aircraft can expand their aerodynamic flight envelopes by changing aerodynamic shapes, significantly improving the scope of application and flight efficiency. A novel 3D Zero Poisson’s Ratio (ZPR) honeycomb structure is designed to meet the flexible deformation requirements of morphing aircraft. The 3D ZPR honeycomb can deform in the three principal directions with smooth borders and isotropic. Analytical models related to the uniaxial and shear stiffnesses are derived using the Timoshenko beam model and validated using the quasi-static compression test. The Poisson’s ratio of the 3D ZPR honeycomb structure has an average value of 0.0038, proving the feasibility of the 3D ZPR concept. Some pneumatic muscle fibers are introduced into the system as flexible actuators to drive the active deformation of the 3D ZPR honeycomb. The active 3D ZPR honeycomb can contract by 14.4%, unidirectionally bend by 7.8°, and multi-directions bend under 0.4 Mpa pressure. Both ZPR properties and flexible morphing capabilities show the potential of this novel 3D ZPR configuration for morphing wings. Full article

(This article belongs to the Special Issue Aircraft Morphing Systems 2.0)

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22 pages, 14035 KiB

Open AccessArticle

Aerodynamic Analysis of Camber Morphing Airfoils in Transition via Computational Fluid Dynamics

by Bruce W. Jo and Tuba Majid

Biomimetics 2022, 7(2), 52; https://doi.org/10.3390/biomimetics7020052 - 22 Apr 2022

Cited by 7 | Viewed by 4167

Abstract

In this paper, the authors analyze an important but overlooked area, the aerodynamics of the variable camber morphing wing in transition, where 6% camber changes from 2% to 8% using the two airfoil configurations: NACA2410 and NACA8410. Many morphing works focus on analyzing the aerodynamics of a particular airfoil geometry or already morphed case. The authors mainly address "transitional" or "in-between" aerodynamics to understand the semantics of morphing in-flight and explore the linearity in the relationship when the camber rate is gradually changed. In general, morphing technologies are considered a new paradigm for next-generation aircraft designs with highly agile flight and control and a multidisciplinary optimal design process that enables aircraft to perform substantially better than current ones. Morphing aircraft adjust wing shapes conformally, promoting an enlarged flight envelope, enhanced performance, and higher energy sustainability. Whereas the recent advancement in manufacturing and material processing, composite and Smart materials has enabled the implementation of morphing wings, designing a morphing wing aircraft is more challenging than modern aircraft in terms of reliable numerical modeling and aerodynamic analysis. Hence, it is interesting to investigate modeling the transitional aerodynamics of morphing airfoils using a numerical analysis such as computational fluid dynamics. The result shows that the SST k-ω model with transition/curvature correction computes a reasonably accurate value than an analytical solution. Additionally, the

C_{L}

is less sensitive to transition near the leading edge in airfoils. Therefore, as the camber rate changes or gradually increases, the aerodynamic behavior correspondingly changes linearly. Full article

(This article belongs to the Special Issue Aircraft Morphing Systems 2.0)

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24 pages, 670 KiB

Open AccessArticle

Status and Perspectives of Commercial Aircraft Morphing

by Michelangelo Giuliani, Ignazio Dimino, Salvatore Ameduri, Rosario Pecora and Antonio Concilio

Biomimetics 2022, 7(1), 11; https://doi.org/10.3390/biomimetics7010011 - 07 Jan 2022

Cited by 6 | Viewed by 4535

Abstract

In a previous paper, the authors dealt with the current showstoppers that inhibit commercial applicability of morphing systems. In this work, the authors express a critical vision of the current status of the proposed architectures and the needs that should be accomplished to make them viable for installation onboard of commercial aircraft. The distinction is essential because military and civil issues and necessities are very different, and both the solutions and difficulties to be overcome are widely diverse. Yet, still remaining in the civil segment, there can be other differences, depending on the size of the aircraft, from large jets to commuters or general aviation, which are classifiable in tourism, acrobatic, ultralight, and so on, each with their own peculiarities. Therefore, the paper aims to trace a common technology denominator, if possible, and envisage a future perspective of actual applications. Full article

(This article belongs to the Special Issue Aircraft Morphing Systems 2.0)

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28 pages, 45722 KiB

Open AccessEditor’s ChoiceArticle

Structural Sizing and Topology Optimization Based on Weight Minimization of a Variable Tapered Span-Morphing Wing for Aerodynamic Performance Improvements

by Mohamed Elelwi, Ruxandra Mihaela Botez and Thien-My Dao

Biomimetics 2021, 6(4), 55; https://doi.org/10.3390/biomimetics6040055 - 26 Sep 2021

Cited by 1 | Viewed by 5042

Abstract

This article proposes the integration of structural sizing, topology, and aerodynamic optimization for a morphing variable span of tapered wing (MVSTW) with the aim to minimize its weight. In order to evaluate the feasibility of the morphing wing optimization, this work creates a numerical environment by incorporating simultaneous structural sizing and topology optimization based on its aerodynamic analysis. This novel approach is proposed for an MVSTW. A problem-specific optimization approach to determine the minimum weight structure of the wing components for its fixed and moving segments is firstly presented. The optimization was performed using the OptiStruct solver inside HyperMesh. This investigation seeks to minimize total structure compliance while maximizing stiffness in order to satisfy the structural integrity requirements of the MVSTW. The aerodynamic load distribution along the wingspan at full wingspan extension and maximum speed were considered in the optimization processes. The wing components were optimized for size and topology, and all of them were built from aluminum alloy 2024-T3. The optimization results show that weight savings of up to 51.2% and 55.7% were obtained for fixed and moving wing segments, respectively. Based on these results, the optimized variable-span morphing wing can perform certain flight missions perfectly without experiencing any mechanical failures. Full article

(This article belongs to the Special Issue Aircraft Morphing Systems 2.0)

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22 pages, 10560 KiB

Open AccessEditor’s ChoiceArticle

New Aerodynamic Studies of an Adaptive Winglet Application on the Regional Jet CRJ700

by Marine Segui, Federico R. Abel, Ruxandra M. Botez and Alessandro Ceruti

Biomimetics 2021, 6(4), 54; https://doi.org/10.3390/biomimetics6040054 - 24 Sep 2021

Cited by 10 | Viewed by 5821

Abstract

This study aims to evaluates how an adaptive winglet during flight can improve aircraft aerodynamic characteristics of the CRJ700. The aircraft geometry was slightly modified to integrate a one-rotation axis adaptive winglet. Aerodynamic characteristics of the new adaptive design were computed using a validated high-fidelity aerodynamic model developed with the open-source code OpenFoam. The aerodynamic model successively uses the two solvers simpleFoam and rhoSimpleFoam based on Reynold Averaged Navier Stokes equations. Characteristics of the adaptive winglet design were studied for 16 flight conditions, representative of climb and cruise usually considered by the CRJ700. The adaptive winglet can increase the lift-to-drag ratio by up to 6.10% and reduce the drag coefficient by up to 2.65%. This study also compared the aerodynamic polar and pitching moment coefficients variations of the Bombardier CRJ700 equipped with an adaptive versus a fixed winglet. Full article

(This article belongs to the Special Issue Aircraft Morphing Systems 2.0)

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