Gotowa bibliografia na temat „Soudage par impulsions électromagnétiques”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Spis treści
Zobacz listy aktualnych artykułów, książek, rozpraw, streszczeń i innych źródeł naukowych na temat „Soudage par impulsions électromagnétiques”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Rozprawy doktorskie na temat "Soudage par impulsions électromagnétiques"
Sofi, Khadija. "Optimisation du générateur d'impulsions magnétiques et adaptation énergétique des machines pour les besoins d'assemblage innovants multi-matériaux". Electronic Thesis or Diss., Amiens, 2021. https://theses.hal.science/tel-03856084.
Pełny tekst źródłaMagnetic pulse generators are being used more and more in multi-material forming and welding applications and produce a precise forming of metal parts. This PhD. thesis aims to calculate, using analytical methods, the magnetic field, the magnetic pressure, and the Lorentz force generated during electromagnetic forming of a metal tube. First, we propose to analyze the generator operation using a massive coil in interaction with a magnetic field shaper. Then, we develop the 3D models of these components using FEM and BEM methods in order to determine the evolution of the current and the temperature distributions. In this research work, we experimentally study the impact of the field shaper on the current pulse and then using a thermal camera we measure the temperature distribution in the massive coil. Afterwards, we calculate analytically the distribution of the magnetic field created around the coil based on the mutual inductance of two circular and coaxial coils. Finally, we develop an analytical and numerical study of a tube crimping by magnetic pulses. The used analytical method is based on the calculation of the self-inductance and the mutual inductance of the coil and the tube in 3D order to determine the Lorentz force and the magnetic pressure applied on the tube
Gstalter, Marion. "Assemblage de verre sur verre par impulsions laser femtosecondes". Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAD037.
Pełny tekst źródłaThis PhD thesis is about glass bonding by femtosecond laser pulses. A femtosecond laser source generating high repetition rate laser pulses has been used to weld borosilicate glass plates with high surface quality. The method presented in this work differs from the literature by the focusing system implemented. The influence of the laser parameters on the bonded samples performances has been studied implementing a design of experiments, demonstrating that the mechanical and thermal resistance of the samples can be improved by increasing the amount of deposited. Thebonded samples provide high mechanical resistance, higher than 25 MPa, can held high thermal shock above 300 °C and present high transparency above 90 %. Glass bonding with a distance between the glass plates has been performed by adapting the laser parameters. Bonding of glass on silicon has also been performed successfully
Varin, Charles. "Impulsions d'électrons relativistes ultrarapides à l'aide d'un schéma d'accélération par laser dans le vide". Thesis, Université Laval, 2006. http://www.theses.ulaval.ca/2006/23911/23911.pdf.
Pełny tekst źródłaSonde, Abayomi Emmanuel. "Etude et modélisation de procédés innovants de mise en compression de surfaces : Traitements de surface par cavitation et par impulsions électromagnétiques". Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI015/document.
Pełny tekst źródłaSurface treatments methods like shot peening are used to introduce compressive residual stresses in metallic materials. The compressive stresses prevent the initiation and growth of cracks and hence improve the fatigue life of mechanical parts. The drawbacks and limitations of the existing processes generally used for this purpose are known and have been highlighted in many studies. These are, among others, an important surface modification (roughness), a limited compressive depth, difficulties in execution, debris and contamination problems, etc. Therefore, the interest in new surface treatment methods, which permit to obtain equivalent or even better compressive results while avoiding the previous problems, are growing. Cavitation peening and electromagnetic pulse peening are part of these innovative processes which modeling is the aim of this PhD thesis. Cavitation peening is a process of surface treatment which acts by the generation of cavitation bubbles near the workpiece surface. The modeling of this process is challenging because of the complexity of cavitation phenomenon and the main problematic point is the determination of the mechanical loading on the material due the bubbles collapse. In this thesis, an approach of modeling for cavitation peening based on the study of the dynamics of cavitation bubbles is proposed. Spherical and aspherical collapse of bubbles near a solid surface are studied by some numerical and analytical models. These two sources of loading pressures have been compared and a macroscopic model for cavitation peening have been derived by associating the numerical simulation of the cavitation jet and the localization of the cavitation zone. The comparison between the final residual stress profile calculated with the proposed model and the experimental results were satisfactory. Electromagnetic pulse peening (EMP) is a contactless process of surface treatment which could be used to introduce compressive residual stresses in conductive materials, by the generation of a high transient electromagnetic field. Laplace forces induced in the material by magnetic induction are the source of the material plastic deformation and compressive residual stresses introduction. To predict the EMP results, a numerical model have been built for the process simulation. The model, based on finite element method, coupled successfully electromagnetic and mechanical phenomena by using a sequential-coupled approach. It was proven theoretically, by the study of a reference case, that compressive residual stresses could be induced in metallic materials like nickel-based (Inconel) or aluminum alloys by the means of the present process. It was also shown by the calculations that much higher compressive depths than those of conventional peening processes could be achieved. The parametric study exhibited the influence of the maximum current intensity and frequency which affect both the compressive depth and the maximum residual stress
Moisescu, Georgeta Mihaela. "Effets des champs électromagnétiques sur la membrane cellulaire et applications biomédicales potentielles". Paris 11, 2007. http://www.theses.fr/2007PA114814.
Pełny tekst źródłaThis thesis reports the effects of electromagnetic GSM mobile phones pulses (900MHz, 217Hs, 576µs) with SAR (specific absorption rate) up to 4. 6 W/kg on cellular endocytosis and mitosis. The results here presented report that the fluid phase endocytosis of different cells in culture is stimulated 1. 4 fold under GSM exposure to average SARs above treshold values from 1. 3 to 2. 6W/kg without any bulk temperature increase. The effect was revealed using two exposure setups: a wire patch cell and a TEM cell, at 30°C. The clathrin-mediated endocytosis is the endocytotic pathway perturbed by the GSM exposure. A similar stimulation was observed under exposure to electrical pulses comparable to GSM electrical component suggesting that this electrical component is at the origin of endocytosis perturbation. The GSM exposure of 2. 2W/kg local SAR applied for 1h did not affect the mitosis progression, the total mitosis duration or each mitotic phase duration in our experimental conditions
Jauréguy, Maïté. "Étude de la diffraction par impulsions électromagnétiques très courtes d'objets en espace libre ou enfouis : modélisation numérique et extraction des paramètres caractéristiques". Toulouse, ENSAE, 1995. http://www.theses.fr/1995ESAE0015.
Pełny tekst źródłaWasselynck, Guillaume. "Etude des interactions entre les ondes électromagnétiques de fréquences moyennes et les matériaux composites : application à l'assemblage par induction de ces matériaux". Nantes, 2011. http://www.theses.fr/2011NANT2094.
Pełny tekst źródłaDue to their excellent mechanical properties and their light weight, the composite materials have a growing range of applications in industry. This work focuses on long Carbon Fiber Reinforced Polymer composites (CFRP). During the different steps of life cycle of this material, a heating procedure is necessary. Since carbon fibers are conductive, it is possible to use induction to heat the composite. The purpose of this thesis is to establish a model of induction heating of composites. To model this system, it is necessary to understand the eddy current path in the composite. A CFRP is non homogeneous and highly anisotropic. Furthermore, the fibers are randomly distributed in the matrix and there is an important scale factor between the diameter of fibers which is 7 μm and the size of the composite sheet which may be several meters. To overcome these difficulties, a two scales homogenization method is introduced. The composite is divided into elementary bricks which are statically representative of the whole material. In elementary bricks, the microscopic impedances are calculated to obtain the tensor of electrical conductivities along the 3 axes taking into account the different orientations of fibers in different layers. In the macroscopic scale, these conductivities are introduced in a FEM model to determine the current circulation in the composite. Then, the electromagnetic model is coupled to a thermal problem in order to determine the temperature distribution in CFRP. This coupling takes into account the change of physical properties as a function of the temperature. The developed models were used for the feasibility study of a new assembly technique of CFRP
Courapied, Damien. "Etude de l’interaction laser matière en régime de confinement par eau avec deux impulsions laser. Application au test d’adhérence par choc laser". Thesis, Paris, ENSAM, 2016. http://www.theses.fr/2016ENAM0073/document.
Pełny tekst źródłaThe laser shock wave generation is a novel process becoming more and more common. The shock waves are used to generate mechanicals effects in the sample. The laser absorption results in the creation of a plasma at the surface. This plasma during its expansion creates a shock wave propagating through the sample. This work aims to study the various phenomena involved in the laser-matter interaction. In the field of laser generated shock waves, two different processes exist: the Laser Shock Peening (LSP) and the LASer Adhesion Technique (LASAT). The new challenge deals with the limitations of those processes and the solutions to be setting up to improve them. Some ideas concerning the confinement improvement as water substitution or thermal coatings optimization are suggested in this work. Moreover, the use of double delayed laser pulses allows, for LASAT, the location of main tensile stresses near interfaces. However, for LSP, some aspects dealing with the profitability linked to the peening rate are investigated here. Last but not least, whether the very short (0 to 1000 ns) or very long delays (from 200µs to 200ms), the study of the laser-matter interaction phenomena allows to overcome some limitations for both laser shock processes
Chazottes-Leconte, Aurélien. "Conception et fabrication d'un dispositif de mise en compression par impulsions électro magnétiques (EMP)". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1082.
Pełny tekst źródłaPenning processes are widely used in industries to apply compressive residual stresses into the most solicited part of mechanical pieces. In that way, the compressive residual stresses limit the priming and the propagation of micro-cracks in the material. This increases significantly the lifespan of the treated mechanical piece under fatigue stresses. These existing peening processes have proved their efficiency and also their limitations and weaknesses. The main recurrent defaults are a shallow depth of treatment, a degradation of the surface condition, a random control of the treatment, a material contamination, etc. These problems have led towards the development of news innovative peening processes which allow better performance avoiding some previous defaults briefly evoked. Among these news processes, the electromagnetic peening process seems especially interesting. This process uses high energy electromagnetic fields to induce Lorentz forces into a metallic piece and thus residual stresses. Actually, there is not much information about this process in the literature and no prototype was ever built. The work of this thesis is dedicated to development and realization of an electromagnetic peening prototype. The first chapter of this thesis adresses the state of the art of major peening processes actually in industrial use. Next, the electromagnetic peening process, or EMP process, is described and the electrical needs are exposed. A second state of the art is made about the technological solutions to respond to the EMP needs. The second chapter is about the conception of the EMP prototype with the electrical structure adopted in the previous chapter. The first step is about the inductor sizing to generate an electromagnetic field sufficient enough for a peening application. Next, the storage system is designed depending on the inductor parameters and finally the closing switch is created considering the electrical parameters used for the EMP process. To validate the previous results, a 3D electromagnetic simulation is done. The prototype assembly is presented in the third chapter and also the first experimental test on the EMP prototype. To begin with, an aluminium alloy with low yield strength is selected to be treated. Two different samples forms are used, a thin one, to realize a similar test to the Almen test and thick one to check the EMP depth of treatment. A 3D multiphysics simulation of these experiments is made and these numeric results are next correlated to the experimental ones. In the fourth chapter, an exploratory study is realized on the effects of the residual stresses on magnetic properties of ferromagnetic material, the mumetal
Desplanque, Ludovic. "Caractérisation électro-optique de composants térahertz par échantillonnage Franz-Keldysh subpicoseconde". Phd thesis, Université des Sciences et Technologie de Lille - Lille I, 2003. http://tel.archives-ouvertes.fr/tel-00012147.
Pełny tekst źródłaLes méthodes d'échantillonnage électro-optique basées sur l'utilisation d'un laser impulsionnel femtoseconde constituent une méthode alternative de caractérisation hyperfréquences. Ces mesures dont la résolution temporelle peut être inférieure à la picoseconde permettent d'étudier la réponse en fréquence de composants intégrés jusqu'à plus de 1 THz.
La méthode d'échantillonnage ultra-rapide que nous proposons est basée sur un effet d'électroabsorption présent dans de nombreux semiconducteurs massifs : l'effet Franz-Keldysh. Cet effet nous permet de sonder optiquement des impulsions électriques ultra-brèves se propageant sur une ligne de transmission déposée sur Arséniure de Gallium (GaAs). Ces impulsions sont également générées par voie optique grâce à un matériau photoconducteur ultra-rapide : le GaAs épitaxié à basse température.
La démonstration expérimentale de cette méthode de caractérisation est tout d'abord effectuée en utilisant les propriétés intrinsèques du substrat semiconducteur. Dans un deuxième temps, des améliorations technologiques sont apportées au dispositif expérimental pour permettre une généralisation de la technique de mesure à tout type de substrat. Pour cela, nous avons en particulier mis au point une technique de « lift-off » épitaxial permettant le report des matériaux nécessaires à la mesure sur un circuit ayant déjà subi les étapes technologiques. Ces différentes méthodes de mesure sont ensuite appliquées à la caractérisation de lignes de transmission ou de composants passifs THz. Elles ont permis entre autre la mise en évidence du phénomène de couplage par onde de choc électromagnétique entre deux lignes de transmission coplanaires, ou l'évaluation des paramètres S d'un filtre réjecteur de Bragg intégré sur substrat de quartz jusqu'à 1,2 THz. Enfin, la possibilité d'étudier un transistor bipolaire à hétérojonction à doigt d'émetteur submicronique par cette technique de mesure est envisagée.