104 research outputs found
Analysis of composite wing structures with a morphing leading edge
No full textOne of the main challenges for the civil aviation industry is the reduction of its environmental impact. Over the past years, improvements in performance efficiency have been achieved by simplifying the design of the structural components and using composite materials to reduce the overall weight. These approaches however, are not sufficient to meet the current demanding requirements set for a „greener‟ aircraft.
Significant changes in drag reduction and fuel consumption can be obtained by using new technologies, such as smart morphing structures. These concepts will in fact help flow laminarisation, which will increase the lift to drag ratio. Furthermore, the capability to adapt the wing shape will enable to optimise the aerodynamic performance not only for a single flight condition but during the entire mission. This will significantly improve the aircraft efficiency.
The current research work has been carried out as part of the European Commission founded Seventh Framework Program called „Smart High Lift Device for the Next Generation Wing‟ (SADE), which main aim is to develop and study morphing high lift devices. The author‟s investigation focused on developing a design concept for the actuation mechanism of a morphing leading edge device. A detailed structural analysis has been carried out in order to demonstrate its feasibility.In the first phase of the research the attention was directed on the preliminary design and analysis of the composite wing box. The parameters of the key structural components, such as skin, spars, ribs and stringers were set to satisfy the static stress and buckling requirements. Moreover, numerical and experimental studies were conducted to analyse the static failure and buckling behaviour of two typical composite wing structural components: a spar section and a web and base joint assembly.
In the second stage of the research, a design for the morphing leading edge actuation mechanism was developed. The actuation system was designed in such a way that the target shape was reached with minimum actuation force demand. A geometrical nonlinear FE analysis was conducted to simulate the leading edge morphing deflection and ensure that structural strength requirements were satisfied. Furthermore, the behaviour of the skin integrated with the internal actuation mechanism was modelled under the aerodynamic pressure, at different flight conditions and gust loads, in order to prove that the proposed actuation system can compete with the conventional rigid rib.
This study demonstrated that a feasible morphing leading edge design for a next generation large aircraft wing can be achieved. Developing the readiness of this technology will have a significant impact on aircraft efficiency and considerable contribution towards a more environmental friendly aviation
Autonomous Smart Morphing Wing: Development, Realisation & Validation
No full textWith the increasing desire of the aerospace industry to reduce emissions and fuel consumption, morphing wings have gained much interest due to the ability to adapt the wing shape in-flight for improved energy efficiency and aerodynamic performance. Active wing morphing is a technology that can improve aerodynamic performance continuously through different flight phases. However, a multidisciplinary approach is needed, which integrates the design, modelling, sensing and control methodologies in a multi-objective framework, and allows the smart autonomous morphing wing system to adapt its shape autonomously.The SmartX project was initiated for this purpose at the Delft University of Technology, Faculty of Aerospace Engineering, Department of Aerospace Structures and Materials, aiming to investigate the energy-efficient wing concepts through smart wings.This dissertation presents the Development, Realisation & Validation of a smart morphing wing, the SmartX-Alpha, capable of meeting various real-time objectives with distributed seamless morphing modules. This is done through a holistic approach considering all building blocks of a morphing system presented in four Parts of the dissertation.Part I tackles the sensing approach required to reconstruct the shape of the wing in real-time with a vision-based sensing approach. Part II presents the design, development, realisation and experimental testing of a distributed modular morphing concept, SmartX-Alpha. Part III presents the multi-objective control framework developed to meet the gust and manoeuvre load alleviation objective and the real-time shape optimisation strategy to improve online aerodynamic performance. Furthermore, a vision-based control strategy is proposed to mitigate nonlinearities in the actuation system arising from mechanical imperfections. A series of wind tunnel experiments are conducted in the OJF to validate the methodologies on the SmartX-Alpha, ensuring the objectives are satisfied autonomously, in-real time. The final Part, Part IV presents the development of a second wing demonstrator, the SmartX-Neo, with distributed discretised control surfaces incorporating the previous learnings.Aerospace Structures & Computational Mechanic
Osteoporotic Vertebral Fractures and the Role of Percutaneous Vertebroplasty in Patient Care
No full textBackground: Osteoporosis is an age-related skeletal condition of bone, with increasing prevalence in older populations. Insufficiency of the bone is associated with increased disability and mortality. Vertebral fractures are commonly secondary to osteoporosis, however only a proportion of patients may present clinically with identifiable symptoms. Percutaneous vertebroplasty is an interventional method of managing such patients.Aim: To determine the role of percutaneous vertebroplasty in managing patients with osteoporotic vertebral fractures.Methods: Electronic databases including MEDLINE, Cochrane Library and NHS Evidence were searched for meta-analyses and randomised controlled trials, with some provision given to expert reviews due to the small pool of publications available. Search terms used included “osteoporosis and vertebral fractures”, “vertebroplasty and osteoporosis”, “percutaneous vertebroplasty in the management of osteoporosis”, “vertebral body cement augmentation”, and “balloon kyphoplasty”. Results: Vertebroplasty reduces pain in the short-term (up to 2 weeks) after surgery and has sustained effects in improving quality of life. The long-term effects are difficult to establish due to the underlying osteoporosis disease progression and comorbidities.Conclusion: Vertebroplasty is worthwhile in treating acute vertebral fractures associated with pain. However more research is needed to fully determine its effectiveness in the long term
Design and Analysis of a Distributed TRIC concept Seamless Smart Morphing Wing
No full textThis thesis embarked upon establishing and validating a design process to build and control a distributed TRIC concept seamless smart morphing wing to achieve simultaneous load alleviation, flutter suppression and drag minimization capabilities. A novel aeroelastic simulation tool was built to carry out composite wing skin optimization, with prototype testing carried out to design a flexible connection between modules. The work output was a fully built morphing wing which was successfully tested in the TU Delft Open Jet Facility. Control of the wing was partially made feasible through the development of a surrogate model of the system which was also validated with DIC testing.https://www.youtube.com/watch?v=SdagIiYRWyA&t=1s Smart-X Alpha DemonstratorAerospace Engineerin
Adaptive Wing: Investigations of Passive Wing Technologies for Loads Reduction in the CleanSky Smart Fixed Wing Aircraft (SFWA) Project
No full textIn the work package “Adaptive Wing” in the Clean-Sky “Smart Fixed Wing Aircraft” (SFWA) project, design processes and solutions for aircraft wings have been created, giving optimal response with respect to loads, comfort and performance by the introduction of passive and active concepts. Central activity of the work was the design and optimization of adaptive wing structures, for complete wings as well as for special components. This process, often called "aeroelastic tailoring", formed the backbone of the work package. Other important contributions have encompassed the development and improve-ment of methods for loads analysis, by extending the classical linear tool set by fast non-linear approach-es. Partners from industry and research involved in the work package contribute with special expertise to the process.
The paper gives an outline of the objectives and the work done in the work package, as well as an over-view of the integration of the “Adaptive Wing” activi-ties in the framework of the SFWA project
Design of a Smart Morphing Wing Using Integrated and Distributed Trailing Edge Camber Morphing
No full textIn this study, the design and development of an autonomous morphing wing concept were investigated. This morphing wing was developed in the scope of, the Smart-X project, aiming to demonstrate in-flight performance optimisation. This study proposed a novel distributed morphing concept, with six Translation Induced Camber (TRIC) morphing trailing edge modules, interconnected triangular skin segments joined by an elastomer material to allow seamless variation of local lift distribution along the wingspan. An FSI structural optimisation tool was developed, to achieve this optimised design, and to produce an optimal laminate design of fibre Glass weave material, capable of reaching target shapes and minimise actuation loads. Analysis of the kinematic model of the embedded actuator was performed, and a conventional actuator design was selected to continuously operate at the required load and fulfil both static and dynamic requirements in terms of bandwidth, actuation force and stroke. Preparations were made in this study for the next stage of the Smart-X design, to refine the morphing mechanism design and build a functional demonstrator for wind tunnel testing.</p
SMART MORPHING CONCEPTS AND APPLICATIONS FOR ADVANCED LIFTING SURFACES
No full textThe aim of this thesis has been the study and implementation of structural solutions for the local or global change of airplanes wing geometry (adaptive wing): they may lead to an increase in aerodynamic efficiency and reduced operating costs and maintenance, as well as the structural complexity through the use of "smart" materials. In particular, attention has been paid to three parameters: the formation of a dorsal bump, the trailing edge curvature and the airfoil chord. Innovative aspects of this research concern the use of “smart” materials with an high structural integration and the development of solutions in full scale for use on regional civil transportation aircrafts. Developed methodologies have been both theoretical-numerical, to simulate the thermomechanical behaviour of Shape Memory Alloys (SMA) and its integration into a Finite Element approach in commercial software, and application-experimental, with the manufacture of prototypes and tests in laboratory. Major achievements included the construction and validation in laboratory of several original morphing architectures for load-bearing surfaces. The full functionality against the requirements and a discrete numerical-experimental correlation has been demonstrated. One of the investigated solutions is based on an innovative actuator based on SMA: its use in the aeronautical field, however, is one of many possible applications. Novelty of the studies and interest shown by the industrial partner (Alenia Aeronautica) have conducted at the request of an European patent (patent pending), and further funding of such studies to proceed with industrialization of the proposed architectures (TIAS project)
Design and Development of a Seamless Smart Morphing Wing Using Distributed Trailing Edge Camber Morphing for Active Control
No full textIn this study, the design and development of an autonomous morphing wing concept were investigated. The morphing wing was developed in the scope of the Smart-X project, aiming to demonstrate in-flight performance optimisation. This study proposed a novel distributed morphing concept, with six Translation Induced Camber (TRIC) morphing trailing edge modules, interconnected with triangular skin segments joined by an elastomer material to allow seamless variation of local lift distribution along the wingspan. A FSI structural analysis tool was developed, to achieve a feasible design, capable of reaching target shapes and minimising the actuation loads with fibreglass weave material. A conventional actuator and kinematic mechanism were selected such that both static and dynamic requirements in terms of bandwidth, actuation force and stroke were fulfilled. The integration of smart sensing technologies and active morphing design developed for the Smart-X wing is facilitated in static and dynamic wind-tunnel tests at the Open Jet Facility (OJF) at the Delft University of technology, with multi-objective control of the active morphing system.Virtual/online event due to COVID-19Aerospace Structures & Computational Mechanic
Internal systems design for smart fixed wing technologies using knowledge based engineering
No full textThe growing awareness of our environment demands the aviation industry to produce eco-friendly and more efficient aircrafts. To support this the Clean Sky Joint Technology Initiative (JTI) is developing and improving breakthrough technologies, that will be demonstrated on a flying prototype. The Clean Sky JTI is split up into six technology domains; one of these is the Smart Fixed Wing Aircraft (SFWA). This domain aims to develop and test a new wing design that makes use of passive and active flow and load control technologies. Department of Systems Engineering and Aircraft Design (SEAD) at Delft University of Technology has been asked to develop a simulation framework to support the internal systems design on the Smart Fixed Wing Aircraft. During this thesis work a parametric model and framework has been created for two flow control technologies and their pneumatic supply system. The model is based on Knowledge Based Engineering (KBE) techniques, which aim to increase the productivity of engineers and allow more detailed and fair concepts trade-offs. The two selected ‘smart technologies’ are Hybrid Laminar Flow Control (HLFC) and Fluidic Actuated Flow Control (FAFC). The first extends laminar flow using a combination of Natural Laminar Flow and Boundary Layer Suction. The second delays separation, stalling and buffeting by reenergising the boundary layer using pulsating or synthetic jets. The parametric model creates a 3D representation of various internal system concepts, which is used to evaluate the Internal Aerodynamics, External Aerodynamics (HLFC only), weight and cost. The internal aerodynamic analysis uses handbook relations and has been incorporated into the KBE environment. It has been validated for conceptual design with limited success. External aerodynamics is performed with a link to Xfoil-suc. The cost and weight are currently based on component and (sheet-)material price and weight. The product model created in this thesis work can evaluate multiple concepts of the internal system for both ‘smart technologies’ and thereby allow a more detailed and fair trade-off. Due to the lack of available input specifications, e.g. aircraft-type and external aerodynamic data, a trade-off between the concepts could unfortunately not yet be made.Systems Engineering and Aircraft DesignAerospace Engineerin
Smart Morphing Concepts and Applications for Advanced Lifting Surfaces
No full textIn this research study, aeronautical "structural" morphing has been considered, focused
on seamless structural wing shape adaptation, inspired by biologicallife.
Available literature (Chapter 2) shows that international interest in the aeronautical field
is focused in the morphing of specific wing parameters, such as leading or trailing edge
curvature, wing torsion, wing span change, etc., each capable of generating
aerodynamic advantages or better adaptability over a traditional design.
Moreover, to overcame weight, mechanical complexity and costs penalties introduced
by morphing architectures, many of these solutions adopt smart materials as actuators.
Among them, Shape Memory Alloys have attracted a lot of attention and are present in
many applications, due to their favourable force/volume or force/weight ratio: state of
the art about SMAs features, numerical modelling and characterization is presented in
Chapter 3.
The chief objective of this dissertation is to propose plausible architectural solutions for
changing different geometrical parameters of an airfoil; many of them integrate Shape
Memory Alloys within the structure, having both actuation and load-bearing role.
In particular, three airfoil parameters have been taken into account:
airfoil (upper) bump;
airfoil camber at trailing edge (morphing flap);
airfoil chord.
The formation of an airfoil upper bump is one of the first experiences in the morphing
field done by the author and researchers at CIRA: it represents one of the less invasive
possible morphing techniques, not affecting the wing primary load-bearing structure,
and capable of introducing some benefits in transonic regime (Chapter 4).
Then, activities moved towards a greater level of integration and interaction within the
wing structure, trying to substitute a traditional hinged flap with a variable camber
trailing edge, also known as morphing flap (Chapter 5). In parti cular , literature showed
a dearth of real scale applications of morphing technologies with smart materials to civil
transportation class aircrafts. Basing on the partnership with Alenia Aeronautica Spa
industry (which founded part of these activities) , innovative concepts for a morphing
flap have been conceived, suitable for real scale regional transportation aircrafts;
expertise at CIRA in modeling and characterization of Shape Memory Alloys allowed
for an high integration of these alloys both as actuators and structural load-bearingelements. Results of this collaboration brought to the design and manufacture of a
SMA-based actuator (Chapter 6) and a morphing flap architecture highly integrating
such an actuator devi ce (Chapter 7). Moreover, these research activities have raised
great interest in the industriaI partner (Alenia): a patent is pending on both devices
(Appendix) and further studies and collaborations are currently starting.
Finally, new research activities started in the branch of variable chord are presented
(Chapter 8). Chord morphing has the power to increase the airfoil surface and, so, its
lifting capab il ity. Something similar already happens for high lift devices on
transportation aircrafts, where the typical single/double slotted solution for trailing edge
flaps allow not only to increase wing curvature, but also its chord (that is, wing area).
The possibility to match the greater aerodynamic efficiency of a morphing flap with an
airfoil chord (wing area) increase could lead to even better aerodynamic performance.
In this work, an early concept has been studied and manufactured for a morphing
rotorcraft bIade, basing on a three-month collaboration with the Department of
Aerospace Engineering of the Pennsylvania State University (with particular reference
to the Vertical Lift Research Centre of Excellence (VLRCOE)).
The thesis, where possible, has been produced as a collection of publications (both on
journals and to conferences). However, due to the patent pending on some of the
presented activities and prototypes, great part of the research activities has not been
published yet at the moment of writing: for this reason, some chapters will be offered as
traditional reports.
Therefore, the dissertation is organized as follows:
Chapter 2 treats the worldwide state of the art in morphing technologies through
a survey of aeronautical applications that can be found in literature, focused in
the optimization of specific wing parameters, using traditional actuators or
Shape Memory Alloys;
Chapter 3 overviews the Shape Memory Alloys micromechanics and
macroscopic behaviour, together with material modelling and characterization;
then, current applications in various fields exploiting either the super-elastic or
shape memory effect are presented, jointly with new discovered materials in the
"shape memory" field;
Chapter 4 introduces the first studied morphing application, focused on the
bump formation on the upper wing skin for transonic drag reduction (paper): a
device integrating Shape Memory AlIoys has been designed, manufactured and
tested;
Chapter 5 reviews some preliminary studi es carried out toldentify possible
morphing solutions, actuated by SMAs elements, to produce a camber change
Iocalized to the aft part of a wing airfoil, so to mimic a trailing edge flap: several
architectures are presented and numerical results discussed (various papers);
Chapter 6presents the conceived SMA-based smart actuator, expIaining in great
detail its design features and alI the considerations, numerical simulations and
optimizations which brought to the final prototype, experimentalIy tested and
characterized;
Chapter 7 shows in detail an application of the developed smart actuator to a
real scale morphing architecture abIe to mimic a trailing flap: after numerical
simulations, the solution has been built and prototype tested also in presence of
static Ioads;
Chapter 8 deals with the other morphing parameter taken into account in this
research, that is airfoil chord, introducing an early concept for a morphing
rotorcraft bIade, its design constraints and the realized prototype;
Chapter 9 c10ses and comments on the work presented, discussing also future
deveIopments.
Finally, an Appendix is present, reproducing the patent communication from the
European Patent Office with all the details
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