Aeroelasticity

A special issue of Aerospace (ISSN 2226-4310). This special issue belongs to the section "Aeronautics".

Deadline for manuscript submissions: closed (31 December 2018) | Viewed by 87638

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Faculty of Engineering and Physical Sciences, University of Southampton, Southampton SO171BJ, UK
Interests: aerodynamics; structures; aeroelasticity; model reduction; control
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Dear Colleagues,

The impact of aeroelasticity on the design and operation of aerospace vehicles cannot be underestimated. Aeroelastic phenomena are encountered at various spatial and temporal scales, from low Reynolds number vortical flows around membrane and flapping wings to high Reynolds number, transonic flows around complete aircraft. If discovered in the late phases of the aircraft development process, aeroelastic issues may degrade the overall aircraft performance and even cause catastrophic failures. Traditionally, aerospace vehicles are designed to avoid the occurrence of aeroelastic phenomena within the flight envelope. The methods that aid in bringing a conceptual design into fruition are primarily analytical, semi-empirical and based on linear methods. These methods have fast turnaround times, but their predictive capabilities are restricted to linear or linearised conditions. On the contrary, the increasing use of physics-based computational models is driven by the need to increase the accuracy of predictions and reduce, concurrently, the uncertainty in the model formulation. This Special Issue on Aeroelasticity aims at collecting current trends in the field, which may include the modelling and experimentation of nonlinear aeroelastic phenomena and testbeds, the development of methods and tools to support the design of next generation aerial vehicles, the control of aeroelastic phenomena for loads alleviation purposes and for energy harvesting.

Dr. Andrea Da-Ronch
Guest Editor

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Published Papers (13 papers)

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Editorial

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2 pages, 155 KiB  
Editorial
Special Issue: Aeroelasticity
by Andrea Da Ronch
Aerospace 2019, 6(9), 92; https://doi.org/10.3390/aerospace6090092 - 23 Aug 2019
Cited by 1 | Viewed by 3750
Abstract
Aeroelasticity belongs to the larger family of fluid-structure interaction problems that are characterized by the interplay between a fluid and deforming body [...] Full article
(This article belongs to the Special Issue Aeroelasticity)
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Research

Jump to: Editorial

13 pages, 2388 KiB  
Article
Energy Harvesting Performance of Plate Wing from Discrete Gust Excitation
by Yun Cheng, Daochun Li, Jinwu Xiang and Andrea Da Ronch
Aerospace 2019, 6(3), 37; https://doi.org/10.3390/aerospace6030037 - 15 Mar 2019
Cited by 7 | Viewed by 5302
Abstract
Energy harvesting from aeroelastic response tends to have a wide application prospect, especially for small-scale unmanned aerial vehicles. Gusts encountered in flight can be treated as a potential source for sustainable energy supply. The plate model is more likely to describe a low [...] Read more.
Energy harvesting from aeroelastic response tends to have a wide application prospect, especially for small-scale unmanned aerial vehicles. Gusts encountered in flight can be treated as a potential source for sustainable energy supply. The plate model is more likely to describe a low aspect ratio, thin plate wing structure. In this paper, the Von Kármán plate theory and 3D doublet lattice method, coupled with a piezoelectric equation, are used to build a linear state-space equation. Under the load of “one-minus-cosine” discrete gust, the effects of flow speed and gust amplitude, thickness of piezoelectric ceramic transducer (PZTs) layers, and mounted load resistance are investigated. Results reveal that the PZTs layers on the wing root of the leading edge can obtain the highest electrical parameters. The flow velocity, thickness of the PZTs layers and load resistance are used to optimize energy harvesting data. Full article
(This article belongs to the Special Issue Aeroelasticity)
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24 pages, 26580 KiB  
Article
CFD-Based Aeroelastic Sensitivity Study of a Low-Speed Flutter Demonstrator
by Vladyslav Rozov, Andreas Volmering, Andreas Hermanutz, Mirko Hornung and Christian Breitsamter
Aerospace 2019, 6(3), 30; https://doi.org/10.3390/aerospace6030030 - 06 Mar 2019
Cited by 6 | Viewed by 8346
Abstract
The goal of developing aircraft that are greener, safer and cheaper can only be maintained through significant innovations in aircraft design. An integrated multidisciplinary design approach can lead to an increase in the performance of future derivative aircraft. Advanced aerodynamics and structural design [...] Read more.
The goal of developing aircraft that are greener, safer and cheaper can only be maintained through significant innovations in aircraft design. An integrated multidisciplinary design approach can lead to an increase in the performance of future derivative aircraft. Advanced aerodynamics and structural design technologies can be achieved by both passive and active suppression of aeroelastic instabilities. To demonstrate the potential of this approach, the EU-funded project Flutter Free Flight Envelope Expansion for Economical Performance Improvement is developing an unmanned aerial vehicle with a high-aspect-ratio-wing and clearly defined flutter characteristics. The aircraft is used as an experimental test platform. The scope of this work is the investigation of the aeroelastic behaviour of the aircraft and the determination of its flutter limits. The modeling of unsteady aerodynamics is performed by means of the small disturbance CFD approach that provides higher fidelity compared to conventional linear-potential-theory-based methods. The CFD-based and the linear-potential-theory-based results are compared and discussed. Furthermore, the sensitivity of the flutter behaviour to the geometric level of detail of the CFD model is evaluated. Full article
(This article belongs to the Special Issue Aeroelasticity)
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20 pages, 980 KiB  
Article
Structured Control Design for a Highly Flexible Flutter Demonstrator
by Manuel Pusch, Daniel Ossmann and Tamás Luspay
Aerospace 2019, 6(3), 27; https://doi.org/10.3390/aerospace6030027 - 05 Mar 2019
Cited by 21 | Viewed by 7784
Abstract
The model-based flight control system design for a highly flexible flutter demonstrator, developed in the European FLEXOP project, is presented. The flight control system includes a baseline controller to operate the aircraft fully autonomously and a flutter suppression controller to stabilize the unstable [...] Read more.
The model-based flight control system design for a highly flexible flutter demonstrator, developed in the European FLEXOP project, is presented. The flight control system includes a baseline controller to operate the aircraft fully autonomously and a flutter suppression controller to stabilize the unstable aeroelastic modes and extend the aircraft’s operational range. The baseline control system features a classical cascade flight control structure with scheduled control loops to augment the lateral and longitudinal axis of the aircraft. The flutter suppression controller uses an advanced blending technique to blend the flutter relevant sensor and actuator signals. These blends decouple the unstable modes and individually control them by scheduled single loop controllers. For the tuning of the free parameters in the defined controller structures, a model-based approach solving multi-objective, non-linear optimization problems is used. The developed control system, including baseline and flutter control algorithms, is verified in an extensive simulation campaign using a high fidelity simulator. The simulator is embedded in MATLAB and a features non-linear model of the aircraft dynamics itself and detailed sensor and actuator descriptions. Full article
(This article belongs to the Special Issue Aeroelasticity)
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25 pages, 2846 KiB  
Article
Identification of Aeroelastic Models for the X-56A Longitudinal Dynamics Using Multisine Inputs and Output Error in the Frequency Domain
by Jared A. Grauer and Matthew J. Boucher
Aerospace 2019, 6(2), 24; https://doi.org/10.3390/aerospace6020024 - 22 Feb 2019
Cited by 19 | Viewed by 6134
Abstract
System identification from measured flight test data was conducted using the X-56A aeroelastic demonstrator to identify a longitudinal flight dynamics model that included the short period, first symmetric wing bending, and first symmetric wing torsion modes. Orthogonal phase-optimized multisines were used to simultaneously [...] Read more.
System identification from measured flight test data was conducted using the X-56A aeroelastic demonstrator to identify a longitudinal flight dynamics model that included the short period, first symmetric wing bending, and first symmetric wing torsion modes. Orthogonal phase-optimized multisines were used to simultaneously excite multiple control effectors while a flight control system was active. Non-dimensional stability and control derivatives parameterizing an aeroelastic model were estimated using the output-error approach to match Fourier transforms of measured output response data. The predictive capability of the identified model was demonstrated using other flight test data with different inputs and at a different flight conditions. Modal characteristics of the identified model were explored and compared with other predictions. Practical aspects of the experiment design and system identification analysis, specific to flexible aircraft, are also discussed. Overall, the approach used was successful for identifying aeroelastic flight dynamics models from flight test data. Full article
(This article belongs to the Special Issue Aeroelasticity)
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12 pages, 4205 KiB  
Article
High-Bandwidth Morphing Actuator for Aeroelastic Model Control
by Sebastiano Fichera, Irma Isnardi and John E. Mottershead
Aerospace 2019, 6(2), 13; https://doi.org/10.3390/aerospace6020013 - 01 Feb 2019
Cited by 17 | Viewed by 5270
Abstract
The design and testing of a high-bandwidth continuous actuator for aeronautical applications is presented hereinafter. The actuator has a dual goal of controlling both the aeroelastic behaviour and the flight mechanics of the model in which it is installed. In order to achieve [...] Read more.
The design and testing of a high-bandwidth continuous actuator for aeronautical applications is presented hereinafter. The actuator has a dual goal of controlling both the aeroelastic behaviour and the flight mechanics of the model in which it is installed. In order to achieve these aims, the actuation bandwidth of the active aerofoil, as well as its static camber variation, have to be sufficiently high. The camber morph is achieved by using tailored piezoelectric patches in a sandwich configuration with a linear trailing edge slider to allow the necessary compliance. The morphing actuator is designed for a NACA 0018 aerofoil with a chord of 300 mm and a span of 40 mm. Static and dynamic experimental tests are carried out on a prototype, and a camber variation control technique is implemented. It is proved that the actuator bandwidth is up to 25 Hz and the equivalent maximum deflection is ± 15 degrees. This solution is shown to be a viable light-weight alternative to the conventional brushless/servo-motor approach currently used in aeroelastic models. Full article
(This article belongs to the Special Issue Aeroelasticity)
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28 pages, 825 KiB  
Article
A Generalized State-Space Aeroservoelastic Model Based on Tangential Interpolation
by David Quero, Pierre Vuillemin and Charles Poussot-Vassal
Aerospace 2019, 6(1), 9; https://doi.org/10.3390/aerospace6010009 - 15 Jan 2019
Cited by 19 | Viewed by 8018
Abstract
In this work, a new approach for the generation of a generalized state-space aeroservoelastic model based on tangential interpolation is presented. The resulting system of differential algebraic equations (DAE) is reduced to a set of ordinary differential equations (ODE) by residualization of the [...] Read more.
In this work, a new approach for the generation of a generalized state-space aeroservoelastic model based on tangential interpolation is presented. The resulting system of differential algebraic equations (DAE) is reduced to a set of ordinary differential equations (ODE) by residualization of the non-proper part of the transfer function matrix. The generalized state-space is of minimal order and allows for the application of the force summation method (FSM) for the aircraft loads recovery. Compared to the classical rational function approximation (RFA) approach, the presented method provides a minimal order realization with exact interpolation of the unsteady aerodynamic forces in tangential directions, avoiding any selection of poles (lag states). The new approach is applied first for the generation of an aerodynamic model for the bidimensional unsteady incompressible flow in the time domain. Next, an application on the generation of an aeroservoelastic model for loads evaluation of the flutter reduced order assessment (FERMAT) model under atmospheric disturbances is done, showing an excellent agreement with the reference model in the frequency domain. The proposed aeroservoelastic model of minimal order is suited for loads analysis and multivariable control design, and an application to a gust loads alleviation (GLA) strategy is shown. Full article
(This article belongs to the Special Issue Aeroelasticity)
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19 pages, 4552 KiB  
Article
A Fast Correction Method of Model Deformation Effects in Wind Tunnel Tests
by Yan Sun, Yuntao Wang, Andrea Da Ronch and Dehong Meng
Aerospace 2018, 5(4), 125; https://doi.org/10.3390/aerospace5040125 - 30 Nov 2018
Cited by 2 | Viewed by 5395
Abstract
The influence of model deformation needs to be corrected before the aerodynamic force data measured in the wind tunnel is applied to aircraft design. In order to obtain the aerodynamic forces on rigid model shape, this paper presents a fast correction method by [...] Read more.
The influence of model deformation needs to be corrected before the aerodynamic force data measured in the wind tunnel is applied to aircraft design. In order to obtain the aerodynamic forces on rigid model shape, this paper presents a fast correction method by establishing a mathematical modelling method connecting aerodynamic forces and wing section torsion. The aerodynamic force coefficients on rigid model shape can then be calculated quickly just by setting section torsion to zero. A 25-point simulation dataset of the High Reynolds Number Aero-Structural Dynamics (HIRENASD) model generated by Computational Fluid Dynamics (CFD) and Static Computational Aeroelasticity (CAE) approach is used to investigate the influence of section locations, basis function type, support radius, and deformation perturbation on the prediction accuracy. Finally, the present correction method is applied to predict the aerodynamic forces on the rigid shape of a NASA common research model. The results of parametric analysis and application show that the present correction method with the Wendland’s C6 function and a support radius of 1.0 can provide a reasonable prediction of aerodynamic forces on the rigid model shape. Full article
(This article belongs to the Special Issue Aeroelasticity)
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17 pages, 4808 KiB  
Article
Natural Frequencies of Rectangular Laminated Plates—Introduction to Optimal Design in Aeroelastic Problems
by Aleksander Muc
Aerospace 2018, 5(3), 95; https://doi.org/10.3390/aerospace5030095 - 10 Sep 2018
Cited by 21 | Viewed by 7339
Abstract
Free vibration (or eigenvalue analysis) is a prerequisite for aeroelastic analysis. For divergence analysis, slope influence coefficients (rotation at point i due to unit load at point j) are calculated using free vibration mode shapes and corresponding frequencies. The lowest eigenvalue is [...] Read more.
Free vibration (or eigenvalue analysis) is a prerequisite for aeroelastic analysis. For divergence analysis, slope influence coefficients (rotation at point i due to unit load at point j) are calculated using free vibration mode shapes and corresponding frequencies. The lowest eigenvalue is of interest and gives the divergence speed. The present paper considers the maximization problem of eigenfrequencies for composite panels. The influence of boundary conditions and constant or variable stiffnesses on optimization results are investigated herein. A new convenient set of design variables is employed in the analysis. The computations are carried out with the use of the Rayleigh–Ritz method and Finite Element analysis (2D quadrilateral and 3D solid elements). Full article
(This article belongs to the Special Issue Aeroelasticity)
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24 pages, 2133 KiB  
Article
Unsteady Lifting Line Theory Using the Wagner Function for the Aerodynamic and Aeroelastic Modeling of 3D Wings
by Johan Boutet and Grigorios Dimitriadis
Aerospace 2018, 5(3), 92; https://doi.org/10.3390/aerospace5030092 - 01 Sep 2018
Cited by 27 | Viewed by 10963
Abstract
A method is presented to model the incompressible, attached, unsteady lift and pitching moment acting on a thin three-dimensional wing in the time domain. The model is based on the combination of Wagner theory and lifting line theory through the unsteady Kutta–Joukowski theorem. [...] Read more.
A method is presented to model the incompressible, attached, unsteady lift and pitching moment acting on a thin three-dimensional wing in the time domain. The model is based on the combination of Wagner theory and lifting line theory through the unsteady Kutta–Joukowski theorem. The results are a set of closed-form linear ordinary differential equations that can be solved analytically or using a Runge–Kutta–Fehlberg algorithm. The method is validated against numerical predictions from an unsteady vortex lattice method for rectangular and tapered wings undergoing step or oscillatory changes in plunge or pitch. Further validation is demonstrated on an aeroelastic test case of a rigid rectangular finite wing with pitch and plunge degrees of freedom. Full article
(This article belongs to the Special Issue Aeroelasticity)
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19 pages, 3033 KiB  
Article
Adaptive Feedforward Control for Gust-Induced Aeroelastic Vibrations
by Yongzhi Wang, Andrea Da Ronch and Maryam Ghandchi Tehrani
Aerospace 2018, 5(3), 86; https://doi.org/10.3390/aerospace5030086 - 10 Aug 2018
Cited by 11 | Viewed by 5938
Abstract
This paper demonstrates the implementation of an adaptive feedforward controller to reduce structural vibrations on a wing typical section. The aeroelastic model includes a structural nonlinearity, which is modelled in a polynomial form. Aeroelastic vibrations are induced by several gusts and atmospheric turbulence, [...] Read more.
This paper demonstrates the implementation of an adaptive feedforward controller to reduce structural vibrations on a wing typical section. The aeroelastic model includes a structural nonlinearity, which is modelled in a polynomial form. Aeroelastic vibrations are induced by several gusts and atmospheric turbulence, including the discrete “one-minus-cosine” and a notably good approximation in the time-domain to the von Kármán spectrum. The control strategy based on the adaptive feedforward controller has several advantages compared to the standard feedback controller. The controller gains, which are updated in real-time during the gust encounter, are found solving a minimization problem using the finite impulse responses as basis functions. To make progress with the application in aeroelasticity, a single-input single-output controller is designed measuring the wing torsional deformation. For both deterministic and random atmospheric shapes, the controller was found successful in alleviating the aeroelastic vibrations. The impact of the control action on the unmeasured structural modes was found minimal. Full article
(This article belongs to the Special Issue Aeroelasticity)
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18 pages, 8608 KiB  
Article
Numerical Continuation of Limit Cycle Oscillations and Bifurcations in High-Aspect-Ratio Wings
by Andrew J. Eaton, Chris Howcroft, Etienne B. Coetzee, Simon A. Neild, Mark H. Lowenberg and Jonathan E. Cooper
Aerospace 2018, 5(3), 78; https://doi.org/10.3390/aerospace5030078 - 24 Jul 2018
Cited by 17 | Viewed by 5989
Abstract
This paper applies numerical continuation techniques to a nonlinear aeroelastic model of a highly flexible, high-aspect-ratio wing. Using continuation, it is shown that subcritical limit cycle oscillations, which are highly undesirable phenomena previously observed in numerical and experimental studies, can exist due to [...] Read more.
This paper applies numerical continuation techniques to a nonlinear aeroelastic model of a highly flexible, high-aspect-ratio wing. Using continuation, it is shown that subcritical limit cycle oscillations, which are highly undesirable phenomena previously observed in numerical and experimental studies, can exist due to geometric nonlinearity alone, without need for nonlinear or even unsteady aerodynamics. A fully nonlinear, reduced-order beam model is combined with strip theory and one-parameter continuation is used to directly obtain equilibria and periodic solutions for varying airspeeds. The two-parameter continuation of specific bifurcations (i.e., Hopf points and periodic folds) reveals the sensitivity of these complex dynamics to variations in out-of-plane, in-plane and torsional stiffness and a ‘wash out’ stiffness coupling parameter. Overall, this paper demonstrates the applicability of continuation to nonlinear aeroelastic analysis and shows that complex dynamical phenomena, which cannot be obtained by linear methods or numerical integration, readily exist in this type of system due to geometric nonlinearity. Full article
(This article belongs to the Special Issue Aeroelasticity)
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16 pages, 3214 KiB  
Article
Transient Temperature Effects on the Aerothermoelastic Response of a Simple Wing
by Gareth A. Vio, David J. Munk and Dries Verstraete
Aerospace 2018, 5(3), 71; https://doi.org/10.3390/aerospace5030071 - 02 Jul 2018
Cited by 2 | Viewed by 4757
Abstract
Aerothermoelasticity plays a vital role in the design and optimisation of hypersonic aircraft. Furthermore, the transient and nonlinear effects of the harsh thermal and aerodynamic environment a lifting surface is in cannot be ignored. This article investigates the effects of transient temperatures on [...] Read more.
Aerothermoelasticity plays a vital role in the design and optimisation of hypersonic aircraft. Furthermore, the transient and nonlinear effects of the harsh thermal and aerodynamic environment a lifting surface is in cannot be ignored. This article investigates the effects of transient temperatures on the flutter behavior of a three-dimensional wing with a control surface and compares results for transient and steady-state temperature distributions. The time-varying temperature distribution is applied through the unsteady heat conduction equation coupled to nonlinear aerodynamics calculated using 3rd order piston theory. The effect of a transient temperature distribution on the flutter velocity is investigated and the results are compared with a steady-state heat distribution. The steady-state condition proves to over-compensate the effects of heat on the flutter response, whereas the transient case displays the effects of a constantly changing heat load by varying the response as time progresses. Full article
(This article belongs to the Special Issue Aeroelasticity)
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