Tesis sobre el tema "Avion électrique"
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Zhang, He. "Gestion décentralisée de réseaux continus à forte disponibilité en aéronautique". Thesis, Lille 1, 2010. http://www.theses.fr/2010LIL10032/document.
Texto completoThe electrification trend is for all modes of transportation, particularly in the next generation of commercial aircrafts. This trend began with the Airbus A380 and Boeing 787 and it will continue. The replacement of mechanical, hydraulic and pneumatic power transfers by an electrical one is one of the most important innovations of the More Electric Aircraft in the aspect of ecologic and economic (weight reduction, energy efficiency increasing, maintenance costs reduction, etc..). The development of a local power exchange network, like a DC one, should facilitate this process. Some local electricity production, bi-directional loads and energy storage and dissipation system, are then interconnected by a DC bus, via some appropriate protections. Several power management strategies are proposed. Depending on the objectives, constraints and means of action envisaged, some tools have been implemented. In the case of a multiple objectives strategy, fuzzy logic appears to be a well suited tool . Moreover, being based on rules, this tool allows to develop naturally a power management strategy in considering several constraints. Two indicators to evaluate performance of these supervision strategies have been proposed (energy efficiency and voltage variation). These indicators help to choose a strategy of supervision, and provide criteria for sizing the storage and dissipation system. These supervision strategies were tested experimentally. The stability of the local DC network was analyzed in small signal. It is shown that the hybrid system with the associated energy management strategy can help to increase the stability margin of this type of network. The currently power connection being implemented in on-board systems is not reversible in power. To make it reversible necessitates a complete redesign of the protections. The problem of short-circuit protection and fault isolation has been investigated. A method to select the branch in insulation failure is proposed. It is tested using the Saber simulation tool that takes into account the characteristics of real components. The work in this thesis can be generalized and to be applied in other fields such as electric or hybrid vehicles, rail systems …etc
Brunello, Julien. "Conception de convertisseurs de puissance DC-DC isolés pour l'avion plus électrique". Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS187/document.
Texto completoThe electric aircraft tends to become widespread at all the main manufacturers of the domain of the aeronautics. Needs do not stop growing and require setting up reliable, efficiency and modular systems of conversion of energy. These systems of conversion are often coupled with systems of storage of energy (battery) allowing in certain situations to make the punctually autonomous aircraft energetically thanks to a source of power independent from main organs of power production. This interconnection battery - network of edge presents a very high report of rise of tension what, added to the high current value of the battery bus, in fact a particularly complex object to be realized.The objective of this thesis is to design in an optimal way a converter of power isolated allowing the interconnection of a low-voltage bus 28V (typically batteries) in a high-voltage bus 540V (network of edge of the aircraft) with an exchangeable power about 12 kW. It takes place within the framework of an ANR project (four university partners + AIRBUS) the development of tools of conception of which one of the tasks is for the ENP. The corresponding work includes a contribution to this task in the form of the construction of models of the main components occurring in a converter, model intended to be integrated into the routines of optimization. For that reason, they will be analytical (physical, empirical or mix both).These models will then be inserted into a global tool developed in another thesis of the project, by means of which various architectures of converters will be compared to deduct the best solution from it for the previous specifications. A prototype of the reserved converter will be finally realized by using advanced technologies, to lead an experimental validation
Bérubé, Daniel. "Conception et simulation d'une alimentation hybride de secours pour un avion plus électrique". Mémoire, École de technologie supérieure, 2011. http://espace.etsmtl.ca/988/1/B%C3%89RUB%C3%89_Daniel.pdf.
Texto completoBonenfant, Laurent. "Modélisation et simulation du réseau électrique d'un avion : application aux Airbus A330, A340 et A3XX". Toulouse, INPT, 1998. http://www.theses.fr/1998INPT002H.
Texto completoAndrade, André de. "Conception intégrée par optimisation multicritère d’un système d’actionnement pour le conditionnement d’air d’un avion plus électrique". Thesis, Toulouse, INPT, 2013. http://www.theses.fr/2013INPT0145.
Texto completoThe concept of More Electric Aircraft (MEA) implies new challenges especially due to the increase of the electrical embedded power. By this way, necessary improvements in terms of safety, energy efficiency and weight reduction are required. For this reason, the design of devices should be more approached with a view to the whole system than as separated elements. In order to facilitate power system integration and to ensure power quality aboard, this dissertation proposes an Integrated Optimal Design (IOD) of the input filter and the inverter feeding the High Speed Permanent Magnet Synchronous Motor (HSPMSM) by taking the flight mission into account. The Environmental Conditioning System (ECS) is equipped of the studied cabin air compressor with a rated power of 70 kW: a Multiobjective Genetic Algorithm (MOGA) is applied to achieve the CIO process. Considering the ECS as a whole, this thesis can be divided into three main parts: components sizing of the electromechanical conversion chain; local and sequential design of each system components (HSPMSM optimization loop followed by “voltage source inverter + input filter” optimization loop); simultaneous design of all system components (global optimization loop). Pareto-optimal solutions obtained from sequential and simultaneous design approaches are presented, analyzed and compared. Results clearly highlight the advantage of using a single optimization loop for the whole system in order to improve mass and efficiency
Métral, Jérôme. "Modélisation et simulation numérique de l'écoulement d'un plasma atmosphérique pour l'étude de l'activité électrique des plasmas sur avion". Châtenay-Malabry, Ecole centrale de Paris, 2002. http://www.theses.fr/2002ECAP0868.
Texto completoA ionized gas (or plasma) has the ability of absorbing or reflecting electromagnetic (radar) waves if its ionization rate is high enough. This is particularly interesting for aeronautics. This study aims at predicting the electric and energetic characteristics of a weakly ionized air plasma in an atmospheric pressure flow. The plasma is described by a two-temperature model, coming from the non-equilibrium description of plasmas. Plasma flow is then described by a two-temperature hydrodynamic system coupled with a collisional model (energy exchanges rates) and a kinetic model (chemical reactions). An algorithm was built to simulate plasma flow in axisymetric geometry. The algorithm is a 2D Lagrange + Projection scheme. The projection step was adapted to multi-components advection, using a second order, non oscillating, and bidimensionnal scheme. This algorithm allows the simulation of experiments concerning atmospheric pressure plasma and then the validation of the model parameters. In a second part, we study the Perfectly Matched Layer (PML) which is a boundary condition to simulate wave propagation in open domains. This method is particularly efficient for electromagnetic problems, and we want to enlarge this approach to aeroacoutics problems (linearized Euler equations). We propose two solutions: a practical approach to avoid numerical oscillations of the solution and a more general approach which consists in a new absorbing layer formulation which leads to well-posed problems
Jacquet, Arnaud Georges. "Nouveau concept de lois de commande intégrées pour un système de freinage d'avion". Mulhouse, 2008. http://www.theses.fr/2007MULH0878.
Texto completoThe present study is focused on the design and the validation of a new braking strategy for aeronautical applications. The analysis extends from the control of the brakes to the integration of the braking algorithms at the aircraft level. The redesign of the braking architecture is needed because of the emergence of some new functions with the aim of helping the manoeuvres of the aircraft during taxiing phases. Furthermore, the classical hydraulic brake will sooner or later be substituted for the electric one and the braking algorithms need to deal with the two technologies in a transparent way. Braking of vehicles has been studied for decades now. Among the whole literature, it has been shown that the control laws based on some behavioral models of the system can greatly reduce the complexity of the controller. But, the observation of the physical parameters governing the dynamics of the wheel is difficult. Taking advantage of a newly available brake torque sensor, the main characteristics of the evolution of the adhesion torque with respect to the wheel slip can be estimated. Then, the rotational behavior of the wheel is fully determined. Finally, a predictive controller is advantageously used to prevent excessive skid of the wheel and to optimize the braking level in a simple process
Ounis, Houdhayfa. "Conception intégrée par optimisation multicritère multi-niveaux d'un système d'actionnement haute vitesse pour l'avion plus électrique". Phd thesis, Toulouse, INPT, 2016. http://oatao.univ-toulouse.fr/18400/1/OUNIS_Houdhayfa.pdf.
Texto completoThauvin, Jérôme. "Exploring the design space for a hybrid-electric regional aircraft with multidisciplinary design optimisation methods". Phd thesis, Toulouse, INPT, 2018. http://oatao.univ-toulouse.fr/23607/1/Thauvin_jerome.pdf.
Texto completoMahiddini, Florian. "Modélisation couplée Compatibilité Électromagnétique - Thermique d’architectures de câblages électriques embarquées". Thesis, Toulouse, ISAE, 2018. http://www.theses.fr/2018ESAE0007/document.
Texto completoThe on-going development of “more” or “all” electrical aircraft leads to the design of ever-complex embeddedelectrical networks, which causes a significant increase of electrical cables to be used within these innovativevehicles. Among the constraints encountered during the definition and integration phases of the network, thoserelated to the electromagnetic compatibility between equipment as well as the management of thermal heatingby Joule’s effect become more and more stringent. Thus, this thesis is dedicated to the development of anoriginal methodology enabling the prediction of both induced and crosstalk currents as well as the heating upstate in complex bundles of cables. Indeed, literature review explicitly shows that electrostatic and stationaryheat transfer phenomena are, from a mathematical standpoint, strictly the same which allows the simultaneouscomputation of these two problems for an arbitrary network. This research work demonstrates that the determinationof primary electrical parameters (per unit length) and the temperature distribution within a givencross-section can be handled with the numerical Method Of Moment (MoM). This choice is motivated by theseveral inherent advantages of the method like an optimized use of the computer resource and the naturalparallelization of the algorithms. The developed numerical tools, intended to be fully integrated in the in-housesoftware suite CRIPTE, has been validated during an experimental campaign that has involved several typesof bundles. Although the comparisons between experimental and simulated results comply with each other,experiments reveal the hard task of getting a precise estimation of the heat transfer coefficients, even in awell-controlled environment. Finally, these works open new and very promising perspectives for future EWIS(Electrical Wiring Interconnection System) in term of mass optimization
Djaouti, Abderrahmane. "Étude de l’intégration d’un stabilisateur/limiteur supraconducteur dans un réseau DC autonome". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0367.
Texto completoThe stability problems that exist in embedded DC networks are mainly due to the presence of power converters. Indeed, in an embedded DC network, the interaction between poorly damped RLC input filters and constant power loads, such as inverter-fed actuators and batteries with charge controllers, can be the source of DC bus voltage instability. This instability results in increasing current and voltage oscillation in the transmission lines, which can lead to the destruction of the components of the network. The main objective of this thesis is to propose a new stabilization method based on a superconductor device by exploiting its properties. Indeed, superconductors become resistive when an external magnetic field is applied to them. Thus, by varying the magnetic field applied on the superconducting tape, its critical current can be modified so that the tape behaves as a dynamic resistor controllable by the magnetic field. By integrating this superconducting tape controlled by the magnetic field in series with the input filter of a DC network, the stability margin can be increased according to the power demanded by the load. In order to study this method, it is necessary to determine the resistance of the superconducting tape at each instant of the network operation. This resistance is non linear and depends on the temperature, the current and the external field Rsc(T;I;Bext). For this, in a first step, a multiphysics model is proposed. This model is developed in a numerical tool allowing the simulation of the system in different regimes (stationary and transient). Then, it is inserted in an equivalent DC network of a more electric aircraft to study the proposed method. The difficulty of this new stabilization method consists in the practical possibility to vary dynamically the resistance of the superconducting tape by an external magnetic field without thermal runaway in order to have a sufficient resistance per length unit to stabilize a DC network. In order to experimentally validate the principle of the method, it is proposed the dimensioning, the design and the characterization of a magnetic inductor to create a variable magnetic field which will allow to realize experimental measurements on a superconducting tape. The experimental results, obtained on a test bench in the GREEN laboratory, allowed to validate the principle of the proposed method
Hadbi, Djamel. "Formulations de problèmes d’optimisation multiniveaux pour la conception de réseaux de bord électriques en aéronautique". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT115/document.
Texto completoWithin more electric aircraft context, electric systems and networks have to evolve. High energy density integration pushes designers to reconsider their systems, architectures and tools.An aircraft network contains a large number of multidisciplinary systems which come from different manufacturers. Each manufacturer designs its system separately following quality standards specified by the aggregator. The goal of this thesis is to provide system approaches which could deal with the high-level of complexity of the network while reaching the optimal design of all the system and so reduce the total weight in comparison with mechanistic approaches based on independent optimization loops for the different subsystems.Consulting MDO “Multidisciplinary Design Optimization” researches, we have developed a multilevel approach based on our previous studies and conclusions on classical approaches used in the design of electrical systems. The optimization concerns the input filters of the loads connected to the HVDC bus and the output filter of the generating channel which supply the electric power. The multilevel collaborative optimization allows an automated exchange of data between the aggregator (system level) and manufacturers (sub-system level) and thanks to that, the optimal design of all the system is joined. The strong points of this approach are the aggregated formulation and causality connections between sub-systems
Morentin, Etayo Alvaro. "Methods and tools for the optimization of modular electrical power distribution cabinets in aeronautical applications". Phd thesis, Toulouse, INPT, 2017. http://oatao.univ-toulouse.fr/17846/1/Morentin_Etayo.pdf.
Texto completoBeciu, Andreea-Livia. "Commande robuste à haute performance sans capteur de position d'alterno-démarreurs à grande vitesse avec un fort couple à l'arrêt pour les avions plus électriques". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLC078.
Texto completoThe aircraft manufacturers express the need to develop a more "electric" aircraft. This brings forward new requirements for the electric drive systems in terms of increasing the available on-board power and resource sharing in order to optimize the overall mass and cost. Among the ongoing studies on the evolution of motor drives, a particular interest is given to the development of multi-level brushless synchronous starter/generators (BSSG). These drives are likely to provide the high torque required to start-up the reactors to which they are associated. For this purpose, the knowledge, at any time, of the rotor position is essential. However, adding a dedicated sensor impacts on the design of the machine, increasing volume, cabling needs and cost. For this purpose, investigating on “sensorless” control laws will permit to avoid using such a sensor and to simplify the design of the Starter/Generators.Using a fine modelling of the machine, this work studies the conditions of feasibility for sensorless control and analyzes several techniques for this purpose. A new method of estimation of the shaft-position, particular to the BSSG architecture is proposed and then illustrated with experimental results. This technique is based on the processing of the existing harmonic components naturally in the stator of the machine and allows the estimation of the position at standstill and the very low speed. To extend the estimation to the whole speed range, a study of position estimation using a state observer using the complete model of the machine considering the knowledge of the existing (or injected) harmonic components in the stator currents is proposed. This observer can be applied to the brushless synchronous starter/generator but also on generic synchronous machines. In this study, its performance is illustrated on a permanent magnet synchronous machine
Liscouet, Jonathan. "Conception préliminaire des actionneurs électromécaniques : approche hybride, directe/inverse". Thesis, Toulouse, INSA, 2010. http://www.theses.fr/2010ISAT0001/document.
Texto completoThe aim of this thesis is to propose innovative methods for the preliminary design of electromechanical actuators (EMA), and to implement them in software tools rapidly available for the industry. This objective is motivated by a strong demand of the industry, especially in aeronautics within the frame of the development of more electric aircrafts. First, this thesis puts forward a hybrid methodology (top-down/bottom-up) to generate and select systematically architectures with respect to requirements and the state of the art of technology. Second, methods to evaluate architectures in terms of power, integration (geometrical envelop and mass), reliability and closed loop performances are developed. The implementation of these methods is based on non-causal modelling combined to direct and inverse numerical simulations. Scaling laws, representative of the main sizing phenomena, are established to reduce the complexity of the models and the need for domain experts during the preliminary phases. The proposed methods and their implementation within the simulation framework Modelica/Dymola have been applied successfully to the examples of electromechanical actuators for the steering of a nose landing gear, the primary flight control of an aircraft and the thrust vector control of a space launcher. As a result, the duration of the architecture evaluation has been reduced from day-scale to hour-scale
Dos, Santos Victor. "Modélisation des émissions conduites de mode commun d'une chaîne électromécanique : Optimisation paramétrique de l'ensemble convertisseur filtres sous contraintes CEM". Thesis, Toulouse, INPT, 2019. http://www.theses.fr/2019INPT0021/document.
Texto completoOver the last decades, aircraft manufacturers have not ceased to increase the electrical power on board aircrafts. This intensification of the use of electricity, in order to rationalize the secondary energies of the aircraft, lays the foundation for the concept of the More Electric Aircraft (MEA). One of the counterparts to increasing the number of the electrical loads is that they must operate in the same electromagnetic environment, which creates compatibility issues. This discipline has been treated so far at the end of the development of a system, before the stage of certification and aircraft integration. Taking into account these constraints from the design phase, via the estimationof conducted and radiated electromagnetic disturbances by simulation, significant time and costs savings could be achieved by reducing the test phases. The first step of this research project is the implementation of a modeling approach suitable with optimization processes. It is then essential to take into account all subsystems that form the electromechanical drive, namely the LISNs, the cables, the power converter and the electric motor. The modeling approach chosen is of the direct type; it consists of representing the electromechanical chain in the common mode base by two ports networks. This generic model allows us to estimate common mode currents directly in the frequency domain at different locations. Besides, one of the main challenges associated to MEA is thus to drastically increase the power density of electrical power systems, without compromising on reliability. The development of new Wide Bandgap (WBG) semiconductor technologies made of Silicon Carbide, can significantly increase efficiency, performance and power density of adjustable speed electrical power drive systems. Nevertheless, due to their higher switching speed and voltage overshoot, WBG semiconductors used in power converters of an electromechanical chain may have some drawbacks when it comes to ElectroMagnetic Interference. Understanding the switching behavior of WBG components is necessary in order to keep switching speed and overvoltage at a reasonable level. In this PhD thesis, we ensure that the introduction of this emerging technology does not lead to a regression of performance at system level. Once we establish the conducted emissions models, different filtering solutions have been used: external and internal passive filters. An optimization dedicated to the resolution of a multi-objectives problem (mass, losses) and multi-constraints (quality, stability, EMC, thermal, etc.) in order to minimize the mass of the converter is accomplished. Sensitivity studies led to the identification of the design variables which have the biggest impacts on conducted emissions. This tool allows the optimal sizing of the inverter’s components (power module, heat sink, common mode and differential mode filters, close control parameters). The results obtained thanks to the use of a genetic algorithm make it possible to develop trend curvesfor an inverter sizing
Moeneclaey, Julien. "Méthode de conception des bobinages des actionneurs électriques adaptés aux nouvelles contraintes de l'avionique". Thesis, Artois, 2015. http://www.theses.fr/2015ARTO0201/document.
Texto completoThe More Electric Aircraft development is reflected by a bigger use of the electrical actuators, which replace the hydraulic or pneumatic system existing or they can also answer to new needs. The energy distribution on board is based on a high voltage continuous bus of 540V connected to electrical power converter. The electric power wide band gap components (SiC, GaN) improve the converters performances but very steep of voltage edge is imposed on the windings of the electric actuators. Each edge excites a transitory regime including an important surge which corresponds to intense electric fields in the inter-turns insulation of coils. When this repetitive electrical constraint exceeds the partial discharges inception voltage (PDIV), the life time of the organic layer between the turns is strongly reduced. The detailed study of the partial discharges (PD) in the area which separate the enamel wire of the windings allows to locate the area where the PD appears. The use of thermo-bonding, with a bonding thickness adapted, allows to raise PDIV beyond the repetitive edge of voltage for the actuators which work in the pressurized parts of the planes. The orderly windings solutions were tested on impregnated cylindrical coils. This analysis shows that the impregnation increases slightly the PDIV from the inter-turns insulation in proportions that do not totally correspond to the intrinsic characteristics of the used varnish. Therefore, the impregnated coils must be conceived on the basis of the primary insulation performance of the enamelled wire. The turn’s arrangement in an orderly coil allows to distribute the constraints and so to conceive the windings which can resist the compulsory repetitive of voltage spikes by the inverter in low pressures corresponding to not pressurized zones in a plane during the flight. A model, based on HF equivalent schema taking in consideration the first two resonances of the elementary coils, allows to analyse the constraints distribution between the coils connected in series of a machine phase
Ngoua, teu Magambo Jean-Sylvio. "Modélisaton et conception de transformateurs planar pour convertisseur de puissance DC/DC embarqué". Thesis, Ecole centrale de Lille, 2017. http://www.theses.fr/2017ECLI0025.
Texto completoThese thesis works deal with the issue of the planar transformers development for power integration, in the context of the More Electric Aircraft (MEA), where the constraints of volume and weight are paramount. Magnetic components remain a hindrance to the integration of Power Electronics systems and planar components (transformers and inductors) offer an interesting alternative to wound components for reducing the size of converters.In these works, methods, a sizing tool and prototypes of planar transformers (2 and 3 windings) in strip and PCB technology are developed for aeronautical DC / DC converter applications. Firstly, the models allowing the calculation of the losses, the estimation of the temperature rise and the calculation of the leakage inductance are presented and compared in order to design calculation tools for engineers. In a second step, it is shown that the modification of the shape of the angles of rectangular turns makes it possible to significantly reduce the HF copper losses.Based on these tools and results, prototypes of 3-windings planar transformers in multilayer PCBs are developed. Many prototypes are characterized and validate the proposed designing models. Finally, one of these prototypes is integrated and tested in a DC / DC power converter of 3.75kW highlighting the gains obtained
Blanc, Maximin. "Optimisation d’une structure de conversion DC/DC réversible pour application aéronautique de forte puissance". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT115.
Texto completoAvionics is intended to become more and more efficient in terms of energy saving thanks to increased efficiency of embedded system. Today, electricity is presented as the best energy vector compared to hydraulic or pneumatic. This is why current researches aim to focus on power electronic converters in order to meet the future electrical power demand in aircraft networks. This research project presents a DC/DC dual active bridge converter which is expected as the best candidate to meet the complex requirements of an aircraft environment, especially the high voltage dynamics. This persuaded us to study the structure and modulations which are explained and brought face to face with a 3,75kW demonstrator in order to validate the theoretical assumptions. Some food for thought is proposed to extend this work toward a three-port converter to interface multiple network as well as storage systems. The originality of this work is to build a new kind of active conversion system promoting break through technologies to prove it suits to aircraft specifications
Perel, Thomas. "Protection des circuits électriques des avions plus composites et plus électriques : propriétés électriques des varistances élaborées par "Spark Plasma Sintering"". Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2480/.
Texto completoSince several years, manufacturers are interested in composite materials for the fabrication of their aircrafts as well as the electrification on deported equipments related to the concept of "more electric" aircraft. The performance criteria of these technological changes are significant (weight gains, volume, operating cost, efficiency. . . ), but are sources of new problems especially in case of lightning strike. The protection of the equipments after a lightning strike on the aircraft structure must be performed by a system or a component having a highly non-linear current voltage characteristic and able to absorb high energy density. Thanks to their properties, Zinc oxide based varistors seems to be good candidates. Flash Sintering technique or "Spark Plasma Sintering" is a particularly interesting production technique. Indeed, this sintering technique is known to increase the kinetics of densification of materials. Thus, a better control of their microstructure suggests maximized electrical performances for a maximum compactness. The objectives of this work are to study the influence of the sintering method on the electrical properties of the material and to show the advantages and disadvantages compared to a conventional sintering method. For this, an electrothermal model based on the barrier height variation is proposed. On the other hand, different encapsulation ways are tested and some recommendations are proposed concerning theirs choice. Finally, as the decrease of the component grain inevitably leads to a decrease on the maximum permissible energy density, we show the limits of the electrical characteristics obtained on samples sintered by Spark Plasma Sintering
Jac, Julien. "Actionneur électromagnétique à entraînement direct à hautes performances spécifiques : application au domaine aéronautique". Montpellier 2, 2008. http://www.theses.fr/2008MON20006.
Texto completoFu, Jian. "Prototypage virtuel incrémental des actionneurs électromécanique pour la synchronisation en position". Thesis, Toulouse, INSA, 2016. http://www.theses.fr/2016ISAT0008/document.
Texto completoIn the aerospace field, the concepts based on extended use of electricity in “More Electric Aircraft” (MEA) and even “All Electric Aircraft” (AEA), involve electromechanical actuators (EMAs) to replace conventional hydraulic servo actuators (HSAs). When EMAs are used for safety-critical actuation applications like flight controls, some specific issues related to thermal balance, reflected inertia, parasitic motion due to compliance, response to failure (jamming and free-run) and synchronization of EMAs driving independent loads cannot be ignored. The simulation-aided design process can efficiently support the assessment and validation of the concepts fixing these issues. For that, virtual prototypes of EMAs at system-level have to be developed in a structured way that meets the engineers’ needs. Unfortunately, the physical effects governing the EMAs behavior are multidisciplinary, coupled and highly nonlinear. Although numerous multi-domain and system-level simulation packages are now available in the market of simulation software, the modelling process and the engineers’ needs are rarely addressed as a whole because of lack of scientific approaches for model-based architecting, multi-purpose incremental modelling and model implementation for efficient numerical simulation. In this thesis, the virtual prototyping of EMAs is addressed using the Bond-Graph formalism. New approaches are proposed to enable incremental modelling of EMAs that provides models supporting control design, energy consumption and thermal analysis, calculation of reaction forces, power network pollution simulation, prediction of response to faults and influence of temperature. The case of preliminary design of EMAs position synchronization is used to highlight the interests and advantages of the proposed process and models of EMAs
Ortiz, Monroy Alvaro. "Étude de montages redresseurs polyphasés pour le réseau d'alimentation électrique des avions". Thesis, Université Laval, 2013. http://www.theses.ulaval.ca/2013/30250/30250.pdf.
Texto completoThis paper presents a study of polyphase rectifier circuits with suitable performance for power network of aircrafts. The study has been conducted on 6, 9 and 12-phases rectifiers. The characteristics of these rectifying circuits are studied theoretically and models have been developed using the software SimPowerSystems (SPS) to determine the performance of these rectifiers in different operating conditions. The simulation results are evaluated and compared with the avionics standards MIL-STD-704F and RTCA-DO-160G. An experimental study was conducted on a 6-phase commercial rectifier in order to validate the SPS model developed for this rectifier circuit. The measurements were performed on the experimental circuit with different charge levels and the results are compared with those given by the SPS model. The concordance between results is very good, which ensures the accuracy of the model developed.
Reysset, Aurelien. "Conception préliminaire d'actionneurs électromécaniques - outils d'aide à la spécification et à la génération de procédures de dimensionnement pour l'optimisation". Thesis, Toulouse, INSA, 2015. http://www.theses.fr/2015ISAT0003/document.
Texto completoThe aim of this thesis is to bring a package of software tools included in a whole methodology dealing with mechatronic systems design. It comes as an add-on to the work already carried out at the laboratory in the field of the new generation of aircraft actuation systems: electromechanical actuators (EMA). This technology triggers new problematics leading the engineers to modify their development process as early as the specification phase, when mission profiles have to be generated/transformed/analyzed in order to simplify the design and ensure the validation step. Thus a Simulink toolbox has been created to meet the need for an information translator working as an intermediate between airframer and system-supplier. As for all the embedded systems, the designer has to face some performance-lifetime-integration trade-off, which can be considered as an optimization problem described by a set of equations and constraints. Particular attention is paid here to the conditioning of those explicit equations in order to obtain a standardized calculation sequence adapted to many optimization algorithms. The method and implemented software, both based on the graph theory, interact with the designer to inform him on the possible singularity and algebraic loop issues, providing some leads for their resolution. Finally, some preliminary sizing studies of landing gear and primary flight control surfaces (aileron and spoiler) actuation systems are presented to highlight the possibilities brought out by this innovative approach: integrated design with complex kinematics, collaborative multi-partners design, use of response surfaces to speed up the optimization
Ouarti, Nawel. "Modélisation de l'allumage d'un brouillard de carburant dans un foyer de turbomachine". École nationale supérieure de l'aéronautique et de l'espace (Toulouse ; 1972-2007), 2004. http://www.theses.fr/2004ESAE0013.
Texto completoKilani, Khaled. "Faisabilité des courants porteurs en ligne sur un câble triphasé entre un onduleur MLI et un moteur pour des applications avioniques". Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL10011/document.
Texto completoThe objective of "More electric" or "all electric" aircrafts is to replace the hydraulic and pneumatic power by electric sources. However, these changes lead to the increase in the power consumption and the need of communication between systems. This comes at the cost of additional cables and connections with challenges in weight considerations, reliability and maintenance. A possible solution to overcome this problem is the use of powerline communication (PLC) by employing the power cables to support the transmission of information. The main objective of our work is the study of the feasibility of a transmission over a powerline cable connecting a three-phase power converter and motor in an avionic environment. First, the characteristics of the transfer function or insertion gains, measured on a test bench including a motor and an inverter are presented. We initiate our study by considering the case of single input single output (SISO) communication using two wires as physical media. The injection and the reception have been performed by two types of coupling, capacitive or inductive. Then, the study was extended to the case of multiple-input and multiple-output (MIMO) transmission in which signals are transmitted simultaneously on two pairs of wires. In this case, the transfer matrix of the channel has been characterized. The measurements were carried out in two environments: a 3 wires network placed inside a building and a three-phase cable connecting the power inverter and motor.Due to the impact of many pulses produced by Pulse Width Modulation (PWM) inverters, a special effort has been made on the experimental characterization of these pluses and their statistical parameters. This leads to develop a noise model used as an input to a software simulator. Clipping methods and a noise suppression method were studied in order to reduce the effect of impulsive noise. The simulation showed that the transmission using a noise suppression technique preceded by a clip of the received signals is the most efficient, providing a gain of 6 dB compared to a transmission without treatment. Then we were interested in the performance of the HomePlug AV standard in both modes, robust (ROBO) and broadband (AV) in the presence of impulsive noise.Finally, performance in terms of bit error rate (BER) of the MIMO transmission on indoor networks and on a three phase power cable was presented for different types of space-time bloc coding (STBC) and space frequency bloc coding (SFBC). It has been shown that, for a rate of 5 Mbit/s, transmission over the three phase cable in the ROBO mode associated with the SFBC method and MIMO-QPSK modulation, offered a diversity gain of 5 dB without prior channel knowledge at the transmitter
Giraud, Xavier. "Méthodes et outils pour la conception optimale des réseaux de distribution d'électricité dans les aéronefs". Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2014. http://tel.archives-ouvertes.fr/tel-00955887.
Texto completoMaalouf, Haddad Amira. "Sensorless control of brushless synchronous starter generator including sandstill and low speed region for aircraft application". Thesis, Cachan, Ecole normale supérieure, 2011. http://www.theses.fr/2011DENS0008.
Texto completoAujourd'hui, l'aviation est en train de vivre des évolutions technologiques concernant surtout l'attribution de différentes fonctionnalités aux équipements électriques et ceci au détriment d'équipements hydrauliques et mécaniques assurant les mêmes fonctionnalités.Dans le cadre de l'avion plus électrique, le démarrage électrique sans capteurs mécaniques de la turbine de l'avion préoccupe les avionneurs de nos jours. Les problèmes introduits par ce capteur ont été identifiés : problèmes de coût et de poids, problèmes de fiabilité et d'intégration.Ce travail présente alors une commande sans capteurs pour la machine synchrone à trois étages à utiliser durant le démarrage électrique de l'avion. Ceci est réalisé avec trois méthodes de détection de la position selon la vitesse de rotation, basées sur :- l'injection d'un signal à haute fréquence- l'utilisation d'un filtre de Kalman étendu FKE- les fém. du PMG (Permanent Magnet Generator) La première méthode donne de bons résultats d'estimation depuis l'arrêt jusqu'à 8% de la vitesse nominale de la machine. Au-delà de cette vitesse, es valeurs des fém. du PMG deviennent assez élevées pour être utilisées dans l'estimation de la position. De bons résultats sont obtenus à moyenne et haute vitesse.Pour des questions de redondance, le FKE est aussi utilisé. Ainsi, la position estimée peut être fournie par l'un des deux algorithmes à moyenne et haute vitesse.L'implémentation de ces algorithmes est réalisée via une carte FPGA étant donné que celui-ci garantit un temps d'exécution. La rapidité de traitement garantit une estimation de la position quasi-instantanée et donc n'introduit pratiquement pas des retards dans l'estimation
Boubaker, Nadhem. "Étude des pertes atypiques dans les machines synchrones à aimants à hautes performances pour applications aéronautiques". Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTT284.
Texto completoThe main aim of this thesis was to study and experimentally assess the additional iron losses in the stator (electrical lamination steel) of high performance permanent magnet synchronous machines (PMSM) designed for aircraft applications, in relation with the “more-electric-aircraft” project. This international program consists of gradually introducing electrical systems to replace onboard hydraulic and pneumatic systems, for example to power the landing gear wheels (Electric Green Taxiing System)…The extra iron losses are caused by manufacturing processes (cutting, sticking, insulation, stacking, pressing, shrink-fitting, thermal treatment …) and the real conditions of use of electrical motor (namely: rotational flux, saturation, high frequency…). Indeed, the mechanical and thermal stresses during the manufacturing steps can deteriorate the magnetic properties of the material and significantly increase the iron losses. These aspects are difficult to accurately evaluate by analytical models or standard measurements (Epstein frame…) and require experimental assessment to precisely calculate the motor efficiency.First of all, we started by developing a test bench equipped with drive motor: PMSM 8000 RPM ; 42 kW. For accurate assessment, the losses in this machine are separated on the test bench, for example, the mechanical losses (bearings loss & windage loss) have been measured at different speed with a non-magnetic rotor. Rotor magnets eddy-current losses cannot be isolated from iron losses, for this reason they have been calculated using a 3D finite element model. To limit rotor loss we then used a non-conductive retaining sleeve (heat shrink sleeve). In the winding, we used bar-wound conductors, which is an original winding technology developed in our laboratory, and whose advantage among others is the unusual copper fill factor that reaches almost 90%.Subsequently, we explored the high frequency machines (>1 kHz) in order to increase the power-to-weight ratio (cross the threshold of 2.5 kW/kg). We proposed, the following to the analytical and finite element study, a first conventional prototype with a power-to-weight ratio equal to 4.5 kW/kg with: FeCo stator (Vacodur49 0.2 mm), FeSi rotor and NdFeB magnets (N35EH), operated at 1666 Hz, 5000 RPM and 94% efficiency at full load. A second motor had been also proposed with both rotor and winding in aluminum, in this case the power-to-weight ratio reaches around 6 kW with, however, less efficiency (93%).Finally, this HF motor was tested, at no load, on the aforementioned test bench. The experiments were carried out on a multitude of FeCo and FeSi stator core samples coming from different manufacturing processes (insulation: bonding varnish and C-5 varnish; cutting: laser and EDM “Electrical Discharge Machining”; thermal treatment) in real operating conditions of a high frequency PM machine in order to experimentally obtain the famous “additional coefficient” of iron losses (Kadd)
Marlier, Clément. "Modélisation des perturbations électromagnétiques dans les convertisseurs statiques pour des applications aéronautiques". Thesis, Lille 1, 2013. http://www.theses.fr/2013LIL10145/document.
Texto completoSince the 1990’s, electricital energy tends to replace pneumatic and hydraulic energy aboard aircrafts. This allows to reduce weight, volume and maintenance costs of the actuators. Electrical energy is used for more and more variated functions thanks to the generalization of the power converters. These power converters are based on the use of semiconductor devices in switching mode which generates sharp voltage and current variations. This leads to electromagnetic (EMC) issues. In order to obtain the compliance to EMC standards, a heavy and bulky filter is often added to the system, which lower the gain allowed by the transition to electrical energy. In order to optimize the filter added, it is interesting to take into account the EMC at the design step. Thus it is necessary to have a predictive modeling tool. In this thesis, a modeling method of the conducted electromagnetic interference (EMI) emitted valid up to 50MHz by a system is proposed. Thus our work is devided into two parts. First, we propose a modeling method of the propagation paths including power cable. Then, we propose a modeling method of the EMI sources in frequency domain. This method is based on the use of multiple equivalent generators topologies and allows to retranscript the non-linear behaviour of the converters. This method is experimentally validated on a buck-converter and a single phased inverter
Ziegler, Nicolas. "Actionneur électromagnétique linéaire polyentrefer à aimants à hautes performances : applicaton aux entraînements directs pour le domaine aéronautique". Montpellier 2, 2008. http://www.theses.fr/2008MON20017.
Texto completoNasr, Andre. "Nouvelles structures de machines électriques pour la génération embarquée avionique". Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLN065.
Texto completoThis work addresses the subject of the embedded electric generation in future aircraft. The main objective is to find a new electrical machine structures that can meet the new avionic requirements. We have been particularly interested in a Hybrid Excited Flux Switching machine with a Magnetic Bridge (HEFSMMB). The structure of this machine has several advantages such as static excitation sources, a passive rotor and a unique stator structure which makes it possible to have a low residual voltage, thus respecting the safety constraints. We have presented in the first chapter a state of the art on singly and doubly excited flux switching machines. We have also given the rules which define the choice of the number of stator and rotor poles. Chapter 2 was devoted to study the electromagnetic performances of the HEFSMMB using a finite element model. This model has been validated by experimental measurements carried out on a 3 kW prototype. In the final chapter, we have put in place an optimization methodology in order to improve the overall performances of the HEFSMMB and to limit its residual voltage. The optimization results showed much improved performances. It can be concluded that the MCFDEPM is a good candidate to replace the three-stage machine in future aircraft
Onopriienko, Oleg. "Mécanique de rupture des matériaux piézoélectriques avec des conditions électriques mixtes aux faces de la fissure d'interface". Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC085.
Texto completoActive materials, first of all piezoelectric and piezo-electro-magnetic ones, are often used as functional parts of different electronic devices including sensors, transducers and actuators because these materials have the ability to change their shape under electric or magnetic field. In many cases the size of the mentioned devices is relatively small, but nevertheless they can undergo to very large mechanical, electric and magnetic fields. Moreover, these devices are usually constructed of elements which can be manufactured of different materials (piezoelectric or piezoelectromagnetic elements, electrodes etc.). Because of an imperfect adhesion of the mentioned elements different defects, like debonding and delamination, can occur between different elements. These situations may take place during the manufacture and exploitation of the active smart structures. The mentioned defects between different constitutive elements are called interface cracks. These cracks are usually the main reason of constructions failure, therefore, their investigation is very important for avoidance of such failure and providing the reliability of electronic devices. Various methods of the investigation of fracture mechanics problems for piezoelectric and piezoelectromagnetic bodies with interface cracks have been developed up to now. The methods of interface crack investigations essentially depend on the modeling of the electrical conditions at the crack faces. Because cracks are usually filled with some medium (air, silicon oil, water and so on), it is desirable to take the properties of this medium into consideration. On this reason the so called electrically permeable, impermeable and limited permeable crack models are developed and actively used at present. Moreover, the crack faces can be sometimes covered with electrodes or the crack can be filled by conducting fluid. In both cases the so called electrically conducting crack model should be applied. Many problems for interface cracks in the framework of the mentioned electric crack models are already solved, however some important problems remains unresolved till nowadays. The solution of these problems defines the tasks of the present investigation. First of all it should be mentioned that the analytical investigation of interface cracks with mixed electrical conditions at the crack faces are unknown for the author of this thesis. Therefore the first task of the work is related to the investigation of an interface crack in a piezoelectric bimaterial under the action of antiplane mechanical and in-plane electric loadings provided that one part of the crack faces is electrically conducting whilst another one is electrically permeable. Due to the presentation of electromechanical quantities via sectionally-analytic functions the problem is reduced to the combined Dirichlet-Riemann boundary value problem and solved exactly. All electromechanical characteristics along the interface, including the stress intensity factors, are found in a simple analytical form. The second task is devoted to the consideration of a conductive crack and an electrode interaction at a piezoelectric bi-material interface under the action of anti-plane mechanical loading and in-plane electrical field parallel to the crack faces. Special attention is devoted to the consideration of new interface crack model, which is free from the oscillation in case of completely permeable interface (no electrode) outside of the crack. The analytical approach based upon complex potentials method is used. The third task is associated with the first one, but for piezoelectromagnetic material and an additional in-plane magnetic loading. The presentations of mechanical, electric and magnetic quantities via sectionally-analytic functions are found and the problems of linear relationship are formulated and solved exactly for any lengths of electro-magneto conducting and electro-magneto permeable parts of the crack. (...)
Brandelero, Julio Cezar. "Conception et réalisation d'un convertisseur multicellulaire DC/DC isolé pour application aéronautique". Phd thesis, Toulouse, INPT, 2015. http://oatao.univ-toulouse.fr/14246/1/Brandelero.pdf.
Texto completoDiomande, Karamoko. "Modélisation des essais BCI (Bulk Current Injection) pour l’aide à la pré-qualification des équipements embarqués dans la bande [10 kHz - 400 MHz]". Limoges, 2012. https://aurore.unilim.fr/theses/nxfile/default/e5be390e-5299-4fd7-ab44-ff634d25e228/blobholder:0/2012LIMO4040.pdf.
Texto completoAeronautical equipments qualification is an important industrial step because of the increasing disturbance source number, power levels and due to the high level of on-board equipments complexity. The researches made in this PHD focused on the elaboration of tools allowing, using the Multiconductor Transmission Lines (MTL) method, the evaluation of conducted constraints level in the frequency bandwidth [10 kHz - 400 MHz]. The aim is to help first step of equipments qualification. So the main developed tool IMEA is used to characterize the equipments under test and the load box interfaces by automatically generating their linked impedance matrices. These works highlight the fact that it is important to take into account uncertainties on electrical and geometrical normative BCI test setup parameters characterization. We demonstrate that this characterization error is closely connected to interfaces complexity and have to be integrated in the modelling processes. The deterministic frequency modelling limitations are shown due to the size of interface under test. So, we introduce statistical modelling which is suitable for real equipment test case. This method is applied on a simple interface and real one identified to Enhanced VHF Radioaltimeter. We then compute the standard deviations according to the equipment interfaces complexity
Genoulaz, Jérôme. "Contribution à l'Étude du Rayonnement des Câbles Soumis aux Signaux de l'Électronique de Puissance dans un Environnement Aéronautique". Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2008. http://tel.archives-ouvertes.fr/tel-00440974.
Texto completoZeaiter, Amal. "Thermal Modeling and Cooling of Electric Motors : Application to the Propulsion of Hybrid Aircraft Thermal Sensitivity Analysis of a High Power Density Electric Motor for Aeronautical Application Numerical Approach to Determining Windings’ Thermal Conductivity Electro-thermal Models and Design Approach for High Specific Power Electric Motor for Hybrid Aircraft Determination of electric motor losses and critical temperatures through an inverse approach". Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2020. http://www.theses.fr/2020ESMA0015.
Texto completoThe concern of this thesis is the thermal modeling of high-specific power electric motors. The aim is to allow finding the efficient and adequate cooling solutions of the motors designed for hybrid aircraft propulsion application. Two specific power values, 5 kW/kg for the short-term (year 2025) and 10 kW/kg for the long-term (year 2035), are targeted, each with specific requirements. The investigated type of electric motors is the synchronous machine with surface-mounted permanent magnets. This motor type is constrained by relatively low values of maximum allowed temperatures in windings and magnets. Once reached, these temperature values lead to a failure in motor operation or at least to shortening its lifetime. Moreover, with a closed motor design and high heat fluxes generated, the optimization of the cooling is essential.To become acquainted with the issue, a detailed state of the art on electric machine cooling is elaborated. Then, the commonly used techniques and the recent technological advancements are analyzed with respect to our case study. Afterward, in order to predict motor thermal behavior and ensure the monitoring of critical temperatures (windings and magnets), a nodal transient model is implemented and solved on Matlab software. This latter is built for the whole system of the motor and cooling circuit. Specific conditions of the flight are taken into account, particularly the outside air temperature variation in terms of altitude and the flight mission profile. Actually, the motor losses, generating the heat in the machine, vary depending on the motor power during the mission. For the identification of crucial parameters, a Finite-Element study was conducted and corresponding correlations were elaborated to estimate the windings thermal conductivity through polynomial interpolation.Several studies were carried out involving the influence of the thermo-physical properties, the outside temperature, the coolant nature, its flow rate as well as the exchanger surface, on the temperature response of the model. This model has allowed studying several motor designs and proposing adequate cooling solutions. For each target, a final optimal configuration of the motor with its cooling system was adopted.Besides, since the electromagnetic and mechanical losses are hardly estimated in this machine type, a chapter was dedicated to identifying them through an inverse approach. A sequential technique, that uses Beck’s function specification for regularization, was developed. Three cases of unknown losses, with increasing complexity, were studied, proving the method's reliability. Finally, using the same developed low-order model, the real-time procedure also allows monitoring low-accessibility motor temperatures (specifically hot spots)
Sousa, martins Rafael Alexandre. "Etude expérimentale et théorique d'un arc de foudre et son interaction avec un matériau aéronautique". Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLC080/document.
Texto completoNowadays, the study of the direct effects of lightning on aeronautical structures could be based, at least in part, on simulation tools. Nevertheless, the lack of experimental data on the transient phase of the lightning arc does not allow us to justify the predictive nature of the simulation tools. The objective of this thesis is to produce an experimental database based on the characterization of lightning arcs in standardized situations. These data can be used both for the understanding of the phenomena observed during the tests, but especially as a reference comparable to the simulation tools.First, we are interested in the free arc column in air, without interaction with the electrodes. Furthermore, time- and space-resolved profilesof temperature and pressure are evaluated by emission spectroscopy. For a 100 kA arc, it is shown that the temperature reaches 37400 K in the arc axis at 2 μs after arc ignition, with a corresponding pressure of 45 bar.Second, we are interested in the interaction of the lightning arc with aeronautical materials. The dynamics of the arc roots and the characteristics of the shock wave are analyzed for different aeronautical materials such as aluminum or carbon fiber composites. The thermo-mechanical constraints applied on the material are studied by infrared thermography and by rapid deflection measurements at the center of panel, leading to an evaluation of the pressure exercised by the arc at the attachment point
Thériault, Olivier. "Intégration d'un système vidéo de poursuite de cible à un simulateur "hardware in the loop" d'avion sans pilote et évaluation d'algorithmes de surveillance". Thesis, Université Laval, 2010. http://www.theses.ulaval.ca/2010/27137/27137.pdf.
Texto completoGoddet, Étienne. "Analyse spectrale et surveillance des réseaux maillés de retour de courant pour l'aéronautique". Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT099/document.
Texto completoThe principles of the electrical system design in future aircrafts have to be reconsidered due to the emergence of new composite materials. The use of these materials for the aircraft structure has indeed implied a complete revision of on-board current return path networks. To facilitate this revision, it is proposed to link through the spectral graph analysis the performances of electrical networks with their topology. The aim of this thesis is to give topological drivers that could help the aeronautical engineers during the design process and then to propose a monitoring methodology
Patin, Nicolas. "Analyse d'architectures, modélisation et commmande de générateurs pour réseaux autonomes". Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2007. http://tel.archives-ouvertes.fr/tel-00204509.
Texto completoLinassier, Guillaume. "Étude expérimentale et numérique de l’allumage des turboréacteurs en conditions de haute altitude". Thesis, Toulouse, ISAE, 2012. http://www.theses.fr/2012ESAE0013/document.
Texto completoDesign of aircraft engines requires tests on engine benches. These tests allow characterizing combustor ignition limits, but are extremely expensive and time consuming. In order to limit their number, it is necessary to develop alternative methods enabling to predict the ignition performances of a combustor prototype, for both ground conditions and high altitude conditions, the latter being particularly critical.The purpose of this thesis is to contribute to the development and validation of numerical tools enabling to predict ignition performances of combustor. Validation will be possible using an experimental data base obtained on the MERCATO test bench, at ONERA. This work results from a close cooperation with TURBOMECA. A numerical model, previously developed to predict the ignition of fuel spray following a spark discharge, has been improved. This model has been combined to a multiphysics CFD code (CEDRE) in orderto build ignition map from a mean two-phase flow field, and also to compute the flame propagation stage using RANS approach. In order to validate both methods, experimental characterization of a one-sectorcombustor has been performed on the MERCATO test rig. A complete data base for validation of CFD code isnow available. Comparison of experimental and numerical ignition mapping showed good agreements for the different tests cases, and seems encouraging for an application on an industrial combustor. In the same time,promising results have been obtained with a new experimental three-sector combustor. Its geometry is basedon an industrial combustor, allowing a comparison of ignition performances between the simplified and the industrial combustors
Djiknavorian, Pascal. "Étude des algorithmes d'approximation de fonctions de croyance généralisées". Thesis, Université Laval, 2014. http://www.theses.ulaval.ca/2014/30400/30400.pdf.
Texto completoThis research is about the solving of the computational difficulty of data fusion in the evidence theory of Dempster-Shafer theory and Dezert-Smarandache theory. We study the use of a variety of known approximation algorithms as well as a new approximation algorithm that we propose. We also study known metrics between bodies of evidence as well as two new metrics that we develop. Finally, we study the possibility of using an optimization method to automatically select the parameters of approximation with performance criteria. Keywords: Dezert, Smarandache, Dempster, Shafer, Fusion, Belief functions.
Simon, Coraline. "Méthodologie pour le durcissement et l’accélération d’essais sur composites à matrice céramique aéronautiques". Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0681/document.
Texto completoWith the aim of an introduction in civil aeronautics, the certification of Ceramic Matrix Composites (CMC)requires to demonstrate the correct behavior of the material during the whole lifetime of the aircraft (about50000h), in high-temperature oxidizing environments and under the stress levels required by the applications.The goal of this thesis is to identify a methodology to accelerate ageing tests in order to get, in shorterdurations, results that are representative of the behavior of the material in standard conditions. The studiedcomposite includes a self-healing matrix which efficiency is linked in a complex way to temperature andhumidity. A thorough understanding of degradation mechanisms is therefore required in order to identifyrelevant accelerating levers. The influence of the selected test parameters (water partial pressure, type ofmechanical loading, frequency of cyclic loading, temperature) on the damage kinetics has been analyzed, whilechecking that the damage mechanisms were not modified. Non destructive monitoring techniques are essentialto quantify in real time the damage level of materials under different test conditions: acoustic emissionmonitoring has been used, and an original method of damage monitoring using electrical resistivity has beendeveloped. Two electromechanical models were proposed, describing the evolution of electrical resistance atroom temperature and under oxidizing conditions. Lifetime estimations based on these techniques led topropose a methodology towards accelerated testing on CMCs
Clermont, Paul Daniel Stanley. "Characterization and prediction of flow electrification phenomena in fuel tanks of aeronautical structures". Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2258/document.
Texto completoWith the new generation of composite aircrafts an attention is carried out on fuel systems with respect to prevention of electrostatic discharges (ESD) during the filling phases of the tanks. Most of the work realized in aeronautics (during the 60's) was conducted on metallic fuel tanks. However, the introduction of composite materials has raised new questions, since those materials can have a different behavior than metallic ones with respect to flow electrification, which fully justify new analyses. In order to properly define the tank structures and their protection against ESD hazards, it is crucial to understand how a complex stack of materials (conductive or not, multilayered or homogeneous, painted or not) constituting a fuel tank behaves with respect to the mechanisms of charge creation by flow electrification when these materials are in contact with aviation fuel. The structure of these materials and their electrical properties control the electric potential reached in the tank through a balance between the production, accumulation and leakage of the electrical charge. This potential may exceed the flash point of the fuel vapors/air mixture and induce ignition. Various protective measures can be adopted to control this phenomenon such as using antistatic additives in the fuels, lowering the rates ofthe fuel injection inside the tank, using only bonded metallic tanks or tanks made of non-metallic materials which do not favor charge accumulation or local charge trapping. It is majorly in response to the latter solution that this work is oriented in order to guide optimum choices of materials and a better definition of the tank structures
Audier, Pierre. "Etude d'une décharge à barrière diélectrique surfacique. Application au contrôle d'écoulement autour d'un profil d'aile de type NACA 0012". Phd thesis, Université d'Orléans, 2012. http://tel.archives-ouvertes.fr/tel-00843633.
Texto completoBenhadjala, Warda. "Fiabilité et miniaturisation des condensateurs pour l'aéronautique : de l'évaluation de composants céramique de puissance à l'étude de nanoparticules hybrides céramique / polymère pour technologies enterrées". Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR15271/document.
Texto completoThe improvement of electronic systems for the deployment of all-electric aircrafts depends on the ability of passive components, such as capacitors, to reduce their volume, weight and cost, and to increase their performance and reliability, particularly in the aeronautical environment. In this context, the objective of this thesis was to study and develop novel capacitor technologies for avionics. In the first part of this work, the evaluation of power ceramic capacitors has been discussed. Indeed, the ceramic technology appeared to be one of the few mature solutions meeting the requirements of OEMs. The characterization, the failure mode, effects and criticality analysis (FMECA) and reliability and robustness assessment of commercial components using original architectures (multi-chip capacitors) have been performed. These results have been completed by a more advanced study on the characterization of new ceramics sintered by spark plasma sintering (SPS). The colossal permittivity of these materials could allow to increase reliability and miniaturization of capacitors while maintaining high values of capacitance and voltage rating. The second part, more fundamental, is devoted to the development of core-shell ceramic/polymer nanoparticles for embedded capacitors operating at radiofrequencies. The synthesis and the physicochemical characterization of the nanocomposites as well as the manufacturing processes of the thick film capacitors are first described. A new broadband electrical characterization methodology has been developed to analyze the dielectric properties and the conduction mechanisms of the nanoparticles. The effects of the temperature and the manufacturing process on the device performance have been investigated. In addition, the durability was evaluated