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  • 101.
    Persson, Björn
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Aeroelastic tailoring of a sailplane wing2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this paper a process for how to perform aeroelastic tailoring of a sailplane wing is described. The analysis was carried out with the aid of a Finite Element solver and the aerodynamic loads were calculated with a potential flow solver. The design parameters of the process were mainly the number of carbon fiber plies and their orientation, but it was also possible to change the geometry of some wing features. A new carbon fiber wing, which was to be fitted onto the sailplane Ventus-2c, was modeled. The performance of the new wing was evaluated in a semi viscous wing analysis program, from which a drag polar was obtained for a number of stacking sequences. Static analyses were run for critical flight cases and stacking sequences to make sure that the wing could withstand the aerodynamic loads. In addition, the natural frequencies and mode shapes of the wing were obtained from a modal analysis. In the paper it is further shown that the fiber angles of the laminates have significant impact on the twist and the aerodynamic performance of the deformed wing. In addition, the static margin was calculated for both the configuration with the new wing and the original Ventus-2c wing.

  • 102.
    Philippe, Alexis
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Optimisation of an aeronautic production line through the managementof tools and the shortage of items2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis work is part of a process to ensure the production ramp-up of the A320neo aircraft pylons at Airbus Saint-Eloi factory (Toulouse). The aim of the project was to optimise the production management in order to sustain the transition to a serial production of the assembly lines. The objective of the thesis work was to develop a model to prevent the downtime of the production lines caused by the shortage of the assembly lines or the unavailability of tools on workstations.Firstly, the work investigates the existing models in order to understand the causes of stocks variability. Performance of tools was determined with the Markov chain model. Then, the work provides a method to forecast production needs in terms of items and tools. An algorithm was developed to collect and process the data on the existing resources in order to compare it to the forecasted needs. Solutions were designed to identify the causes of the shortages on the production lines. In addition, by analysing the trends of the shortage of stocks and the availability of tools on workstation, a forecast of long term constraints for production is possible. The method showed promising results to identify and manage the missing items and tooling on the workstations.

  • 103.
    Pothier, Valentin
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Bending modes analysis in atmospheric flight for heavy launcher2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report presents the bending modes study conducted on a heavy launcher. The controller of the launcher takes as inputs the attitude and attitude rate measurements given by the Inertial Measurement Unit (IMU). Since the bending modes generate measurement errors at the IMU location, the study of deformations due to these bending modes is critical to assess the stability of the launcher during the atmospheric flight phase. The goal of this master thesis project is to detect and then select the most excitable bending modes among the large number of modes provided by a detailed structural analysis of the launcher. Only these relevant modes will be later used to generate reduced dynamical models of the launcher in order to efficiently design an appropriate controller. Indeed, considering all the bending modes will dramatically increase the calculation time and will not significantly improve the representativeness of the model at the control law frequency range of interest. To reach this objective, an extended excitability (the maximum of the module of the transfer function between the effective deflection and the considered mode generalized coordinate transported at the IMU location) is defined and computed for each mode. A criterion has been implemented to choose only the relevant modes. The sensitivity study conducted during this master thesis project has shown that with around 20 modes over 200, one can reproduce the dynamic behavior of the complete system. 

  • 104.
    Quentin, Cochard
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Metadata implementation through the Digital Mock-Up2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Airbus is one of the two leaders in commercial aircraft manufacturing. This field of production is the biggest in amount of parts to design, products and assemblies. Moreover, as nowadays computing has become the fastest way to work, not only it has surrounded the current work places physically but also digitally speaking.

    In fact, the big issue of all companies and in particular Airbus, is to manage the flow of data provided by the different engineering teams like design, simulations, testing or production. Currently, the management of this Metadata is poorly developed and it creates loss of time andfrustration when the time has come to find it. To counteract to this growing concern, the Airbus solution project can be resumed by one sentence : "Configuerd Digital Mock-Up as master". It aims at gathering all the data from the different engineering teams and to provide an intuitive way to exploit them through the DMU.

    In the case of my study, I had to work on one aspect of this big project. I discovered the Airbus way of working and supported several projects to improve the cDMU (configuered Digital Mock-Up) as Master.

  • 105.
    Raguin, Emilie
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Vibration environments in an aircraft engine2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    An aircraft engine is a very complex structure made of thousands of pieces and the rotation of some of the pieces create a substantial amount of vibrations. The main sources of vibrations considered are the unbalance on both shafts and the Fan Blade Passing. The aim of this paper is to understand the influence of these two main phenomena on the vibration behavior of the engine. A lot of tests have been done in order to fully understand the response of the turbomachine. The unbalance is a static phenomenon which depends for example on the manufacturing and on the assembly of the blades. However, the Fan Blade Passing is a dynamic phenomenon: the rotation of the fan blades excite the structural shroud facing them which vibrates. The Fan Blade Passing is impacted by aerodynamics and by other phenomena such as the mounting of blades. To study more accurately the Fan Blade Passing, the tests responses were smoothed thanks to a weighted average method. And finally, when carrying out tests on different engines, different factors play a great role in making two tests different from one another. 

  • 106.
    Rigaldo, Alexis
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Aerodynamics Gust Response Prediction2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This project presents the work performed within the aerodynamics department of Airbus Operation SAS inToulouse through a ve months master thesis. This department works with the industrialization and the use of tools developed by laboratories to perform CFD aerodynamic simulations. The primary purpose of the present work was to support the development of gust analysis methods based on CFD. A new gust model has been developed and integrated to the aerodynamic solver elsA.This solver has been used in order to compute the unsteady aerodynamic simulations for both gust loads and forced motions with CFD. The results were then compared with those from a Doublet Lattice Method computation for validation. Once the validation phase was ended with good agreement between the two methods, a Chimera simulation has been carried out.

  • 107.
    Ringertz, Ulf
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Eller, David
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Keller, D. F.
    Silva, W. A.
    Design and testing of a full span aeroelastic wind tunnel model2017Inngår i: 17th International Forum on Aeroelasticity and Structural Dynamics, IFASD 2017, International Forum on Aeroelasticity and Structural Dynamics (IFASD) , 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An aeroelastic wind tunnel model has been designed and built for testing in the Transonic Dynamics Tunnel. The aircraft configuration represents a modern light weight fighter with a swept wing and canards. The model is designed using composite materials for all lifting surfaces and the fuselage shell. The lifting surfaces are attached to an internal backbone structure using aluminum spars and bulkheads to transfer the aerodynamic loads to the sting. The wing design is also made with a strong internal frame to provide strong support for external stores without giving too stiff overall wing properties. External stores interfaces in the form of pylons, sway braces and pre-tension arrangements are modeled with additional detail to provide realistic kinematics. The model is heavily instrumented with accelerometers, strain gauges, and pressure taps. A unique feature of the test set-up was the use of an optical motion tracking system that made it possible to accurately measure model deformations during wind tunnel testing. A new system for unsteady pressure measurements was also used for the test providing accurate unsteady pressure data from almost 200 pressure taps on the wing surfaces. Wind tunnel testing was performed both in air and heavy gas with the model tested in three different configurations. A large amount of unique data was obtained for both static and dynamic aeroelasticty with simultaneous measurements of model deformation and wing surface pressures. 

  • 108.
    Rosén, Anders
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    Edström, Kristina
    KTH, Skolan för teknikvetenskaplig kommunikation och lärande (ECE), Lärande.
    Borglund, Dan
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Kuttenkeuler, Jakob
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    Hallström, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Garme, Karl
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Marina system.
    3+2≠5 eller Programmål för ingenjörsutbildningar i ljuset av Bolognareformen2011Inngår i: 3:e Utvecklingskonferensen för Sveriges ingenjörsutbildningar, 2011, s. 47-52Konferansepaper (Fagfellevurdert)
    Abstract [sv]

    KTH har infört en ny utbildningsstruktur, som innebär att de två sista åren på civilingenjörsutbildningen utgörs av masterprogram samt att studenterna ska vara behöriga att ta ut en kandidatexamen efter tre års studier. Man kan därmed säga att både kandidat och master ligger inbäddade i den femåriga civilingenjörsutbildningen. Kombinationen av utbildningsprogram, examina och utbildningsmål väcker några principiellt intressanta frågeställningar med långtgående konsekvenser för ingenjörsutbildningen. Vi har analyserat dessa frågeställningar och identifierat att vi står inför ett strategiskt vägval där det nu gäller att långsiktigt slå vakt om ingenjörsutbildningens värde som professionsutbildning. En väl genomförd implementering av den nya utbildningsstrukturen kan förena vetenskaplighet med ingenjörsmässighet och därmed väsentligt stärka ingenjörsutbildningen.

  • 109.
    Roucou, Mickaël
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Prediction of the aeroelastic behavior An application to wind-tunnel models2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The work of this paper has been done during a Master thesis at the ONERA and deals with the establish-ment of an aeroelastic state-space model and its application to two wind-tunnel models studied at the ONERA. The established model takes into account a control surface input and a gust perturbation. The generalized aerodynamic forces are approximated using Roger’s and Karpel’s methods and the inertia of the aileron is computed using a finite element model in Nastran. The software used during this work was Capri, developed by the ONERA, and results validity was checked using Nastran. Comparisons between frequency response functions obtained with the aeroelastic state-space model and experimental ones show that the model gives good results in no wind conditions for an aileron deflection input and up to transonic speeds. Differences between model and experiments could be inputable to structural non-linearities.

  • 110.
    Rubin, Felix
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Modelling & Analysis of a TiltWing Aircraft2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The aim of this report is the investigation of a hybrid vertical take-off and landing (VTOL) tilt wing aircraft which is in development at the company Dufour Aerospace. Using a model, programmed in MATLAB® different stages of flight can be simulated and investigated. Maininvestigation area of this report is the transition between cruise and hover conditions of the aircraft.The simulation is based on the six-degree-of-freedom nonlinear equations of motion for aircraft modified for tilt wing operation. The model characteristics have been determined using various CFD programs, wind tunnel data, as well as numerical and handbook methods.The main focus of modeling lies on the static longitudinal aerodynamic coefficients, the propeller and engine coefficients as well as a propeller slipstream model. Furthermore lateral directional aerodynamic coefficients and dynamic effects and a tail blower (Notar) system are modeled.As results, aerodynamic characteristics of the wing in the propeller slipstream are shown and discussed and the transition conditions are investigated by ’trimming’ the model at equilibrium points over its speed range and analyzing the resulting power requirements.

  • 111.
    Saenz Molina, Flavien
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Vibroacoustic Analyses2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The study of vibrations of structures is paramount in the aerospace industry, as parts are subjected to important dynamic loads. A vibroacoustic analysis of structures is thus undergone in order to ensure that they can withstand the acoustic environment. A validated in-house software was proven to be very reliable but commercial solutions could provide further options in terms of modelisation and decrease computation time while being as accurate as the in-house software. In this paper, a benchmark between ArianeGroup in-house vibroacoustic software and MSC Actran is carried out in order to evaluate their performance in terms of computation time. This comparative study shows that ArianeGroup in-house software and Actran converge towards the same PSD acceleration results and both softwares are consistent with SEA calculations at high frequencies. For a small model, the in-house software is as efficient as Actran but its performance decreases as the size of the model increases. A sensitivity study on Actran decomposition parameters shows that accuracy increases with the number of samples and plane waves used at a cost of an increased computation time. Yet, acceptable accuracy can be achieved without compromising on computation time.

  • 112.
    Samuelsson, Mikael
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Evaluation of Stability and Flying Qualities of a Light Unmanned Aerial Vehicle (UAV)2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The objective of this study was to evaluate the  ying qualities of a light unmanned aerial vehicle (UAV) developed by the Thai company AVIA Satcom Co., Ltd. Based on the study changes in design was to be suggested to meet stability requirements and recommendations from European Aviation Safety was based on two dierent analyses. First, the stability characteristics in terms of stability modes were examined by creating a flight dynamics model of the studied airplane. Secondly the controllability of the vehicle was investigated by examining the control surfaces. It was found that the original design of the UAV was dynamically unstable and that the control surfaces were too large making the airplane di-cult to  y in trim condition. By studying the stability characteristics of the simulated airplane it could be concluded that the UAV was dynamically stable for the improved design and thereby meet the requirements and recommendations.

  • 113.
    Schincariol, Mathieu
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Writing of supply chain activities manuals for a manufacturer of aeronautical parts2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The main purpose of this project, at Safran Electronics & Defense, Mantes-La-Ville, France, was to write the manual of activities of the Supply Chain. This manual gathers all the documents needed to explain the operation of the unit and was created at the request of the quality management. After sorting out all the existing documents, the obsolete ones were deleted, the useful ones set in order and some new documents were written. The result of this work is a document containing a description of the management, organization chart, rituals, indicators, and methods of operating and the procedures of the Supply Chain unit. In the meantime, several side projects about lean management were led during this mission: a 5S methodology applied on the desktop folder of the Supply Chain, the creation of a MOOC about logistics and the reorganization of the reception part.

  • 114.
    Seywald, Klaus
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Wingbox Mass Prediction considering Quasi-Static Nonlinear Aeroelasticity2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Nonplanar wing configurations promise a significant improvement of aerodynamic efficiency and are therefore currently investigated for future aircraft configurations. A reliable mass prediction for a new wing configuration is of great importance in preliminary aircraft design in order to enable a holistic assessment of potential benefits and drawbacks. In this thesis a generic numerical modeling approach for arbitrary unconventional wing configurations is developed and a simulation tool for their evaluation and mass prediction is implemented. The wingbox is modeled with a nonlinear finite element beam which is coupled to different low-fidelity aerodynamic methods obtaining a quasi-static aeroelastic model that considers the redistribution of aerodynamic forces due to deformation. For the preliminary design of the wingbox various critical loading conditions according to the Federal Aviation Regulations are taken into account. The simulation tool is validated for a range of existing aircraft types. Additionally, two unconventional configurations, the C-wing and the box-wing, are analyzed. The outlook provides suggestions for extensions and further development of the simulation tool as well as possible model refinements.

  • 115. Shoemaker, M. A.
    et al.
    Chamboredon, Guillaume
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Dittmar, M.
    Van Der Ha, J. C.
    Fujita, K.
    Design and validation of a trajectory estimation system for the Hayabusa sample return capsule2010Inngår i: Spaceflight Mechanics 2010, Pts I-III, Univelt, Inc , 2010, s. 375-394Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Japanese Hayabusa spacecraft will return to Earth in summer, 2010, carrying samples from asteroid Itokawa. Because the sample return capsule will reenter the atmosphere at night, the capsule and surrounding air will appear as a bright light (i.e., "fireball") during the portion of the trajectory with high aerodynamic heating. Kyushu University, in collaboration with the Japan Aerospace Exploration Agency, is developing a ground-based optical sensor system to observe the reentry and estimate the vehicle's trajectory. This paper describes the design and validation currently underway for the proposed system, in preparation for operations in mid-2010. An Extended Kalman Filter (EKF) is used to estimate the capsule's position and velocity, as well as a scale factor on the atmospheric density. Simulations of the EKF show that the capsule's state at the end of the visible portion of the trajectory (i.e., at approximately 25 km altitude) can be estimated with a 1-s uncertainty of 60 m in position and 8 m/s in velocity.

  • 116.
    Shwan Kurdi, Mir
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Nonlinear Attitude Control ofa Generic Aircraft2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Determining suitable controllers for the process of evaluating dynamic per-formance of multiple versions of an aircraft’s aerodynamical, geometric and propulsive properties in its conceptual stage is an expensive task.In this report a proposition is made to utilize a generalized feedback lin-earizing controller that o˙ers the aircraft designer valuable insight into the manoeuvre performance of their aircraft. This is carried out by first estab-lishing fundamental requirements for a controller capable of treating a generic airframe, and formulating the resulting control laws.It is shown in this report, that with a suÿciently simple aerodynamic and propulsive model explicit feedback linearization is possible with satisfactory performance and robustness. Whereas it would be necessary to implement INDI if explicit inverse mappings are not obtainable. Which in turn would introduce additional tuning parameters.Robustness verification is performed in two stages, firstly by introducing a high model uncertainty within the flight control system and showing, via simulation, that the control system successfully performs desired multi-axial manoeuvres whilst managing to maintain the induced side slip below 0.1◦. Secondly by disturbing the aircraft with a discrete side slip. Critical side slip disturbance angle was found to be considerably larger than that for regular aircraft entailing that the used case study may be somewhat over dimensioned with respect to yaw control authority.

  • 117. Silva, W. A.
    et al.
    Chwalowski, P.
    Wieseman, C. D.
    Keller, D. F.
    Eller, David
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Ringertz, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Computational and experimental results for the KTH-NASA wind-tunnel model used for acquisition of transonic nonlinear aeroelastic data2017Inngår i: 17th International Forum on Aeroelasticity and Structural Dynamics, IFASD 2017, International Forum on Aeroelasticity and Structural Dynamics (IFASD) , 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A status report is provided on the collaboration between the Royal Institute of Technology in Sweden and the NASA Langley Research Center regarding the aeroelastic analyses of a full-span fighter configuration wind-tunnel model. This wind-tunnel model was tested in the Transonic Dynamics Tunnel in the summer of 2016. Large amounts of data were acquired including steady/unsteady pressures, accelerations, strains, and measured dynamic deformations. The aeroelastic analyses presented include linear aeroelastic analyses, CFD steady analyses, and analyses using CFD-based reduced-order models. The reduced-order model results also include a comparison of the aeroelastic response of the model in free air and in a computational mesh of the Transonic Dynamics Tunnel in order to determine, computationally, the effects of the wind tunnel on the aeroelastic response. 

  • 118.
    Slettebo, Christian
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    CubeSub: A CUBESAT BASED SUBMERSIBLE TESTBED FOR SPACE TECHNOLOGY2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report is a Master’s Thesis in Aerospace Engineering, performed at the NASA Ames Research Center. It describes the development of the CubeSub, a submersible testbed compatible with the CubeSat form factor. The CubeSub will be used to mature technology and operational procedures to be used in space exploration, and possibly also as a tool for exploration of Earthly environments. CubeSats are carried as payloads, either containing technology to be tested or experiments and sensors for scientific use.

    The CubeSub is designed to be built up by modules, which can be assembled in different configurations to fulfill different needs. Each module is powered individually and intermodular communication is wireless, reducing the need for wiring. The inside of the hull is flooded with ambient water to simplify the interaction between payloads and surrounding environment. The overall torpedo-like shape is similar to that of a conventional AUV, slender and smooth. This is to make for a low drag, reduce the risk of snagging on surrounding objects and make it possible to deploy through an ice sheet via a narrow borehole. Rapid prototyping is utilized wherever possible. Full-scale prototypes have been constructed through 3D-printing and using COTS (Commercial Off-The-Shelf) components. Arduino boards are used for control and internal communication.

    Modules required for basic operation have been designed, manufactured and tested. Each module is described with regards to its function, design and manufacturability. By performing tests in a pool it was found that the basic concept is sound and that future improvements include better controllability, course stability and waterproofing of electrical components. Further development is needed to make the CubeSub usable for its intended purposes. The largest gains are expected to be found by developing the software and improving controllability.

  • 119.
    Stenfelt, Gloria
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Aerodynamics and lateral control of tailless aircraft2012Doktoravhandling, med artikler (Annet vitenskapelig)
  • 120.
    Stenfelt, Gloria
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Ringertz, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Aerodynamics of a Tailless Wind Tunnel Model2009Rapport (Annet vitenskapelig)
  • 121.
    Stenfelt, Gloria
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Ringertz, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Design and construction of aeroelastic wind tunnel models2013Inngår i: IFASD 2013 - International Forum on Aeroelasticity and Structural Dynamics, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The design and building of accurately scaled aeroelastic wind tunnel models is difficult, time consuming and very costly. With the increasing usefulness of computational methods for predicting aeroelastic phenomena, few complex models have been built in recent years. New fighter aircraft projects are also becoming more and more scarce, and transport aircraft have essentially the same configuration since half a decade. This also significantly reduces the need for aeroelastic wind tunnel models. However, there still is an interest in the results from aeroelastic testing. In some cases new and radical configurations may warrant wind tunnel testing and in other cases complex phenomena arising in flight testing may need carefully performed experiments to resolve problems. However, there is definitely a trend towards building models and performing testing in the support of the development of computational methods. The developments in computer technology do not only improve the computational methods for aeroelasticity. Modern Computer Aided Design and Manufacturing techniques can significantly improve the quality and efficiency of the design and build process for aeroelastic models. There have also been some recent improvements in measurement techniques which have proven very useful for testing of aeroelastic wind tunnel models. The paper will present some new design and build techniques developed for the manufacturing of a large scale wind tunnel model of a canard delta wing fighter aircraft configuration. In the build process fiber-reinforced composites will be used, hence, challenges and possible solutions concerning the ability to produce a model with well defined material properties and fiber angles will be discussed. Further challenges arise when both measurement equipment and adjustable control surfaces should be attached inside the model using techniques that are possible to describe with computational methods. In addition, equipment, such as pressure taps, and control surface mechanics need to fit and function in a flexible structure. As a result, the above requirements will lead to necessary compromises in the design, hence, the paper will present the choices taken during the build process and for which reasons. The use of an optical positioning measurement system will also be discussed for both the validation of model properties and non-contact measurement of model deformations during wind tunnel testing.

  • 122.
    Stenfelt, Gloria
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Ringertz, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    High angle of attack and sideslip aerodynamics of a tailless aircraft2011Rapport (Annet vitenskapelig)
  • 123.
    Stenfelt, Gloria
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Ringertz, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Lateral Control of a Tailless Aircraft Configuration2009Rapport (Annet vitenskapelig)
  • 124.
    Stenfelt, Gloria
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Ringertz, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Lateral Stability and Control of a Tailless Aircraft Configuration2009Inngår i: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 46, nr 6, s. 2161-2164Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aerodynamics of a generic aircraft configuration known as Swing was investigated. The configuration used had two trailing-edge flaps on each wing used for control around all three stability axes included pitch, roll, and yaw. Tests are done in the low-speed wind tunnel L2000 at a freestream velocity of 30 m/s corresponding to a Reynolds number of 6.9 · 105 was applied. A NACA-66009 airfoil was used for the wing, and the outer wing section was twisted up 5° around the leading-edge point of the wing. Asymmetric deflections with the same amplitude for both flaps on each wing were applied for roll control. The deflection of the flaps was recorded with a motion capture system. The infrared light was emitted from four cameras and the light was reflected back to the cameras with a scan rate of 100 Hz and the system computed the distance to the markers. The results revealed that a sudden increase in pitch moment were observed at angles of attack above 10° and the flaps deflected with the same amplitude.

  • 125.
    Stenfelt, Gloria
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Ringertz, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Yaw control of a tailless aircraft configuration2010Inngår i: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 47, nr 5, s. 1807-1810Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The yaw control of a tailless aircraft configuration is investigated. The four trailing-edge control surfaces are actuated using electrical servos which are controlled using a custom designed Ethernet interface. Measurements of the yaw moment due to sideslip and due to split flap deflections have been performed using a strain gauge balance for both sting configurations in order to estimate the sting interference effects. The mass moment of inertia J is obtained from a yaw ground vibration test using the yaw sting with a torsional spring installed. Dynamic stability is estimated by performing vibration tests in yaw with the torsional spring installed. The required control surface deflections can be large due to the low dynamic pressure when landing. The configuration uses only four flaps for simultaneous control around all three axes and necessary control surface deflections for pitch, roll and yaw need to be superimposed at all times.

  • 126.
    Stenfelt, Gloria
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Ringertz, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Yaw departure and recovery of a tailless aircraft configuration2011Rapport (Annet vitenskapelig)
  • 127.
    Stenfelt, Gloria
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Ringertz, Ulf
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Yaw Departure and Recovery of a Tailless Aircraft Configuration2013Inngår i: Journal of Aircraft, ISSN 0021-8669, E-ISSN 1533-3868, Vol. 50, nr 1, s. 311-315Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The ability to recover an aircraft from an out-of-control condition is essential both from a safety and from an economical point of view. Investigations show that a significant amount of fatal accidents occur due to loss of control outside the tested flight envelope. For passenger aircraft, safety is of greatest importance; for military aircraft, a pilot's life can be saved by an ejection seat and the remaining loss after an accident is the cost of the aircraft. The purpose of this study was to investigate departure and recovery in the yaw degree of freedom for a tailless aircraft model. In previous studies, stability and control investigations have shown that the model is not stable in yaw for low angles of attack (AOA), and a simple control model has been implemented to handle the instability at moderate sideslip angles. An increase in yaw damping due to deflected flaps is, however, observed. To accurately simulate the departure motion for the current experimental setup by using the preceding equations, a better understanding of the friction is needed.

  • 128.
    Storfeldt, Joakim
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Design benefits with Additive Manufacturingfrom a convective heat transfer perspective2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Nowadays manufacturing processes are rapidly developing. Salt-bath dip brazing is a conventional manufacturing method commonly used by Saab AB to fuse aluminium components in a high temperature salt bath. However conventional manufacturing methods have shown some limitations. Additive Manufacturing, or 3D printing, is a newer technology which has become very popular in the industry offering competitive advantages regarding production time and size, and structural complexity of the components among other aspects. In this work, Additive Manufacturing is investigated to assess if the performance of heat sinks can be increased compared to the salt-bath dip brazing method.

    Geometrical shapes of heat sink-fins were studied by empirical research to compare their characteristics in air-flow, convection and pressure drop. Eight different geometrical shapes have been analyzed using Additive Manufacturing, and the control plate fins was used as a reference for comparison with salt-bath dip brazing. It was found out that the NACA 0010 fins and Square Grid fins geometries gave the best performance with a 63% and 64% decrease in pressure drop per diverted energy compared to the control plate fins, respectively.

  • 129.
    Sundberg, Torbjörn
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Ivchenko, Nickolay
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Borglund, Dan
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Ahlén, Per
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Gustafsson, M.
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Jonsson, C.
    Juhlen, J.
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Neuner, Oliver
    KTH, Skolan för elektro- och systemteknik (EES), Ljud- och bildbehandling (Stängd 130101).
    Sandström, J.
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Sund, E.
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Wartelski, Matías
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Westlund, C.
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Xin, L.
    KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Small recoverable payload for deployable sounding rocket experiments2009Inngår i: Proceedings of the 19th Esa Symposium on European Rocket and Balloon Programmes and Related Research, 2009, s. 281-284Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We present a design of a small payload for deployment from sounding rockets. The payload is intended for measurements in the ionosphere and the acquired data is stored onboard. For a secure recovery of the data and possible re-use of the payload, an inflatable structure is deployed during the payload descent. This reduces the payload speed and protects it from ground impact. On the ground, a localization system is activated, sending the payload position via a satellite link, and providing a radio beacon signal. The proposed small payload will allow high time resolution multipoint measurements in the ionosphere with small separation distances, thus allowing to address a number of unresolved questions in the field.

  • 130.
    Sveinbjarnarson, Unnar Már
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Anomaly Detection based on Boeing 757-200 Flight Data2018Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This paper deals with anomaly detection from collected flight data for a Boeing 757-200currently in use by Icelandair. Previous work on anomaly detection using generated datahas been shown to give good results using multiple linear regression models. Using a similarapproach the paper addresses how the amount of data effects the models ability to detectanomalies. Simple regression approach is compared to a quadratic one and practical use ofmaintenance data in this context is explored. Finally different model variations are investigatedto attempt further root cause analysis of faults.

  • 131.
    Söderman, Filip
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Uncertainty Analysis of the Aerodynamic Coefficients2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis treats an error propagation analysis used to estimate the uncertainty of the aerodynamic coefficients. The propagation methods used in this analysis are a Taylor Series Method and a Monte Carlo Method. The Taylor Series Method uses the partial derivatives of each input variable whereas the Monte Carlo Method uses random and repeated samples from the probability density function of each variable. By comparing the results obtained by the different methods, the results can be validated. Coverage intervals with a coverage probability of 95% are calculated along with the percentage contribution each input variable has on the expanded uncertainty. The results showed that the uncertainty of the coefficients varied between 10% and 20% and negligible differences between the methods were observed. More accurate measurements of the dynamic pressure and the position of the center of gravity are needed in order to decrease the uncertainty.

  • 132.
    Tomac, Maximilian
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Aerodynamik.
    Eller, David
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    From geometry to CFD grids-An automated approach for conceptual design2011Inngår i: Progress in Aerospace Sciences, ISSN 0376-0421, E-ISSN 1873-1724, Vol. 47, nr 8, s. 589-596Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The CEASIOM software developed in the EU-funded collaborative research project SimSAC generates stability and control data for preliminary aircraft design using different methods of varying fidelity. In order to obtain the aerodynamic derivatives by CFD, the aircraft geometry must be defined, computational meshes generated, and numerical parameters set for the flow solvers. An approach to automation of the process is discussed, involving geometry generation and mesh generation for inviscid as well as RANS flow models.

  • 133.
    Tomac, Maximilian
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Aerodynamik.
    Eller, David
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Steps Towards Automated Robust RANS Meshing2013Inngår i: Proceedings of the 4:th CEAS Conference in Linkoping, 2013, Linköping University Electronic Press, 2013, s. 114-123Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The creation of high-quality discretizations for use in viscous flow simulations remains a challenging task. Even with modern software tools and substantial human effort, the application of state-of-the-art mesh generation algorithms in the presence of geometric features such as concave corners may still result in inadequate local mesh configurations, which can severely affect the resolution of important flow features. To address such issues, mesh generation tools for hybrid unstructured grids often expose a considerable number of algorithm configuration parameter. The resulting flexibility does indeed enable the creation of sufficiently resolved hybrid meshes, although the process often requires a very considerable amount of time even for an experienced user. In a production environment where a large number of detailed simulations of single aircraft configuration are performed, the cost in terms of man-hours may be acceptable. For other applications with requirements for short turn-around time, a more automated approach is desirable. Since an automatic mesh generation procedure cannot rely on user intervention for the resolution of geometric complications or edge cases, a robust strategy for the handling of the surface geometry en- countered in realistic aircraft configurations must be implemented.

    The approach presented here is based on a segregated prismatic/tetrahedral mesh generation procedure, and aims to achieve robustness by means of local geometric modifications. Criteria chosen and algorithmic modifications make use of similar principles as in earlier work, but are adapted for the specific requirements of mesh generation for aircraft configura- tions. An existing set of open-source tools is exploited for mesh data structures, file format support, surface mesh generation and tetrahedral volume meshes.

    The mesh generation strategy presented is based on four phases, starting with the creation of a sufficiently resolved surface mesh. In a second step, the envelope mesh of the prismatic boundary layer mesh is determined; the robustness of this stage is the primary contribution of the present work. Thirdly, tetrahedral elements are generated to fill the volume between the envelope of the prismatic layer and the farfield boundaries, and finally, pentahedral elements are grown between adapted wall and envelope mesh.

    The algorithm implemented into existing open source libraries was applied to two applications presented in this study, a fairly simple wing-body-stabilizer configuration typical for a tran- sonic transport aircraft (CRM) and a rather complex, detailed geometry of a delta wing fighter prototype (F-16XL). RANS solutions converged to engineering accuracy are found to yield solutions in close agreement with meshes produced by a well established grid generator for the EDGE flow solver provided that comparable resolutions are used for both the prismatic layer and the tetrahedral domain.

    When comparing mesh generation timings, an interesting observation was made. For the common situation where parallel CFD solutions are performed on a compute cluster, the analyst may be evaluating post-processed results of a simulation based on a mesh created with the method presented in this paper before a serial advancing front mesh generation has even been completed.

    Obviously, this does not mean that there is no need for high-quality advancing-front mesh generation tools. A substantial proportion of relevant geometries and flight conditions likely require more detailed control over mesh generation parameters than is available in a hybrid Delaunay method. However, for routine solutions where serial mesh generation time is a bottleneck, the libraries including the present method can be used to accelerate the turnaround time considerably.

  • 134.
    Touveneau, Marie
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Flexible body kinematics applied to the Ariane 5 launcher2011Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report concerns my internship at EADS Astrium, in the A5 development mechanical loads section, between January 10 and July 8, 2011. There, engineers work with several software such as ADAMS and PERMAS. This internship showed that it is possible to use PERMAS models in an ADAMS simulation by exporting-importing them. Simulations on ADAMS may become much more time consuming and an industrial use of this method is not possible before some improvements on the interface software have been done.

  • 135.
    Treskatis, Tim
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Validation and Optimization of a non-cooperative Sense and Avoid System2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    To complement the established cooperative S&A system named TCAS which uses vertical avoid trajectories, Airbus Defence and Space developed a non-cooperative S&A System which favors lateral avoidance maneuvers. For this non-cooperative system, intruder aircraft are detected by radar before five different avoid trajectories are computed of which the best one is chosen. The presented work consists of the validation and optimization of this S&A System by simulating many different aircraft encounter scenarios. For validation purposes, the probability tables provided by the European Encounter Model (EEM) were used to compute the most probable aircraft encounters. As a result of the optimization process, the number of Near Mid-Air Collisions (NMACs) could be reduced significantly, and flight route constraints were included. More than 85,000 simulations were carried out to assess the performance of the system. The simulations revealed that the performance requirement for the S&A System, namely being at least as good as a human on-board pilot, could be fulfilled for encounter scenarios in which the ownship was flying level.

  • 136.
    Vasseur, Clément
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Automatic MAC-based modepairingfor aero-elastic analyses2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    A method to automatically name structural modes is proposed. It is essentially based on Modal Assurance Criterion (MAC) to pair un-named modes with modes from a reference data base. Each new naming allows feeding the reference data base. A script has been implemented and tested on Rafale and Falcon aircraft simulation data. After operational validations, this method appears to be efficient and reliable. The mode pairing method may be used to track modal evolution of a structure after structural modifications and thereby to predict modal behavior in aero-elastic calculations.

  • 137.
    Wallén, Peter
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Conceptual Simulator Implementation of Flapping Wing Micro Air Vehicle Using FLAMES2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The interest for Flapping Wing Micro Air Vehicles (FWMAV) is growing. With this comes a need for future users to test and evaluate these vehicles with simulations. This study presents a first iteration of an implementation of a FWMAV in FLAMES Simulation Framework. An aerodynamic model based on the widely used quasi-steady blade element approach is presented and a first linearised version is implemented in FLAMES. The simulation model is capable of both manual and autonomous flight. With the first person view a pilot can investigate buildings and objects. The study gives an idea of how FLAMES can be used for this type of simulations. FLAMES provides a good environment for testing the vehicle both individually and in a context with other units.

  • 138.
    Wang, Cong
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Numerical Investigation of Flow Induced Noise in a Simplified HVAC Duct with OpenFOAM2013Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Due to the growing demand for comfort, the noise generated by HVAC components should be considered by the designers. Flow induced noise is one of the major contributors to the noise in HVAC systems. By means of computational aero-acoustics(CAA), the mechanism of noise generationis able to be studiedin the design phase.

    This research has been conducted based on a simplified HVAC duct, aiming to validate a hybrid method in CAA. The hybrid method is an affordable and promising approach for industrial applications. CFD simulation, as the first step of the hybrid method, has been performed. Due to the deficiency of RANS and high computational cost of LES, hybrid RANS-LES approaches are employed to combine sufficient accuracy and reduced cost. Delayed Detached Eddy Simulation (DDES) and Scale Adaptive Simulation (SAS), as the representative hybrid RANS-LES approaches, are performed and compared. CFD results are shown in detail and compared with the experimental measurements available in the literature. The comparison shows a good agreement for the time averaged flow field and a fairly good agreement for uns teady flow phenomena. Discrepancies between numerical results and measurements can be observe dregarding mainly unsteady pressure fluctuations.The influence study of grid, discretization schemes, time step as well as other parametersis also conducted. The insights gained here can serve as a guideline for future complex applications.

  • 139.
    Wang, Tong
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Calculation of Fuel-Optimal Aircraft Flight Profile2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    Sedan världens första konventionella flygplan lyfte 1914 har flygindustrin förbättrats konstant under de 104 åren sedan dess. År 2017 transporterades över 4.1 miljarder passagerare med ungefär 36.8 miljoner flights av världens alla flygbolag. Statistik visar på att ungefär 2% av människoskapad emission av koldioxid kommer från flygindustrin.För att värna om miljön och reducera emission av koldioxid så blir det därmed viktigt att reducera konsumtionen av flygbränsle. Flygplanstillverkare har redan tillämpat många metoder för att spara flygbränsle, såsom förbättringar av aerodynamik för flygplan och förbättring av motoreffektivitet, samt i senare år att applicera kompositmaterial för att reducera flygplanens vikt. För flygbolag så är en lämplig och ekonomisk färdplan hjälpsam för att reducera konsumtion av flygbränsle. Utöver konsumtion av flygbränsle så är även tid en lika viktig faktor för flygbolag. Denna avhandling tar ett flygledningsperspektiv och etablerar en numerisk simulering baserad på dynamic programming för att beräkna den mest optimala vertikala flygbanan som följer ATC:s (Air Traffic Control) begränsningar och som använder sig av högupplöst väderdata.

  • 140.
    Winet, Martin
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Development of an Automated Testing Tool for Flight Dynamic Models2016Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
  • 141.
    Yezeguelian, Axel
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Flygdynamik.
    Modelling and Simulation of a Propulsive Hybridisation for a Light Fixed-wing Aircraft2019Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Propulsive hybridisation fits in with the sustainable development policies of many companies which are part of the transportation industry. Actually, it makes it possible either to reduce fuel consumption or to improve the aircraft performance at a fixed fuel burn. However, the current technologies of batteries restrain a more regular use in light aviation. For this project this issue is confirmed as both the quasi-static performance assessment and the dynamic studies show that the endurance objective cannot be improved with Li/Ion batteries. However, it is possible to act directly on the engine performance by placing a thermal energy recovery system on exhaust gas pipes to take advantage of their high temperatures, greatly boosting the aircraft performance in cruise.

123 101 - 141 of 141
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