Teses / dissertações sobre o tema "Soudage par résistance SPR"
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Mabrouki, Mohamed. "Caractérisation de la tenue mécanique des assemblages bouchon-gaine en acier ODS obtenus par soudage par résistance". Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0044.
Texto completo da fonteOxide Dispersion-Strengthened (ODS) ferrito-martensitic alloys are among the candidate materials for the manufacture of fuel cladding parts for 4th generation nuclear reactors. The « plug-clad » assembly is carried out by the Pressure Resistance Welding (PRW) process; a solid phase welding process known to have a limited impact on the dispersion of nano-oxides in the welded zone compared with fusion welding processes. One of the aims of this work is to assess and understand the effects of PRW on the final mechanical strength of the 11Cr-ODS steel plug-clad assembly. An approach coupling microstructural and mechanical characterizations with numerical simulations (PRW process and mechanical tests) is adopted. The originality of this approach also lies in the development of two specific geometries for tensile samples, enabling the localization of stresses in the welded zone. Indeed, the severe thermomechanical loadings imposed on the material during the PWR process generate microstructural heterogeneities in the material with direct consequences on its mechanical resistance. Complex microstructures in terms of grain size, local texture, phases (ferrite, martensite, residual ferrite) and grain type (recrystallized or deformed) are obtained. The mechanical tests indicate that the mechanical resistance of the welded assembly is primarily associated with the internal zone of the joint plane, forming an angle of approximately 45° with respect to the axis of the clad. This area is submitted to significant plastic deformation, presents the highest hardness values, and exhibits a more pronounced refinement of the microstructure. A second objective is the evaluation of the effects of a post-welding heat treatment on the microstructural properties of the weld and on the mechanical strength of the welded assembly. Its effect is significant if it is carried out above the phase transformation temperature, Ac3, while it is limited if below Ac3. During tensile tests at room temperature, the fracture zone is moved from the welded area to the as-received metal when the assembly has undergone adequate heat treatments
Thieblemont, Éric. "Modélisation du soudage par résistance par points". Vandoeuvre-les-Nancy, INPL, 1992. http://docnum.univ-lorraine.fr/public/INPL_T_1992_THIEBLEMONT_E.pdf.
Texto completo da fonteMonnier, Arnaud. "Etude et simulation du soudage par résistance de matériaux de contact". Paris 11, 2006. http://www.theses.fr/2006PA112329.
Texto completo da fonteThis study is done in the frame of a CIFRE convention between Schneider Electric and the Laboratoire de Génie Electrique de Paris-SUPELEC. The goal is to understand the physical phenomena occurring during the resistance welding process of contact materials and the development of a numerical simulation of the process. An innovating welding device is developed. Experimental tests done with two rivets of copper allow to determine a weldability area. They also show that the dynamic contact resistance allow to follow the heating way in the pieces. Moreover the characterisation tests (ultrasonic images, shear tests, macrographies), that are supplementary, highlight other physical phenomena. The simulation done with the FEM software ANSYS takes into account the coupling between the mechanical, electrical and thermal phenomena. Two supplementary modellings are developed : a macroscopic modelling that takes into account the evolution of the global superficial resistivity versus the force and the temperature and a microscopic modelling that decouples the roughness and the superficial insulating impurities of the contact area. A comparison between the calculated and measured results shows a consistency of them. These modellings that are consistent with the experimental tests allow to extend the study for the welding of a rivet of aluminium with a rivet of copper and to study the influence of the frequency of the rectified current used during the welding
Srikunwong, Chainarong. "Modélisation du procédé de soudage par points". Phd thesis, École Nationale Supérieure des Mines de Paris, 2005. http://tel.archives-ouvertes.fr/tel-00151464.
Texto completo da fontede soudage, la difficulté principale en simulation numérique est la disponibilité de données d'entrée à toutes températures depuis l'ambiante jusqu'au-delà de la fusion. Le couplage des premiers modèles électrothermiques avec des modèles mécaniques permet un bon accord entre expérience et simulation. Une fois qu'un modèle a été validé selon tous les domaines physiques concernés, des résultats comme les cycles thermiques, la taille de soudure ou les contraintes, déformations et état métallurgique résiduels peuvent être utilisés pour mieux comprendre le procédé, pour le piloter ou pour modéliser le comportement des soudures.
Corpace, Fabien. "Soudage par résistance du gainage combustible ODS d'un réacteur nucléaire de 4ème génération". Phd thesis, Université Sciences et Technologies - Bordeaux I, 2011. http://tel.archives-ouvertes.fr/tel-00786263.
Texto completo da fonteGauthier, Élise. "Étude expérimentale et numérique de la dégradation cyclique des électrodes en CuCr1Zr lors du soudage par résistance par point". Lorient, 2014. https://theses.hal.science/tel-01045222.
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Gauthier, Elise. "Etude expérimentale et numérique de la dégradation cyclique des électrodes en CuCr1Zr lors du soudage par résistance par point". Phd thesis, Université de Bretagne Sud, 2014. http://tel.archives-ouvertes.fr/tel-01045222.
Texto completo da fonteGeslain, Edouard. "Soudage par résistance des tôles fines revêtues : formation du noyau dans un assemblage de trois tôles". Thesis, Lorient, 2018. http://www.theses.fr/2018LORIS481/document.
Texto completo da fonteIn the automotive industry, the requirements for polluting emissions lead to light vehicles, especially in decreasing the steel sheet thickness. This work in partnership with ArcelorMittal focuses on resistance spot welding of steel sheets. The aim is to identify the phenomena that induce operating weldability difficulties encountered with an asymmetrical stack of three coated steel sheets, including a very thin galvanized sheet of less than 0.6 mm, a sheet of DP600, and a hot stamped Usibor® sheet. Infrared camera observations show that the initial heating takes placeat the interfaces with the Usibor®1500 sheet, and that the nugget appears inside this sheet, away from the thin sheet. The very high values of the electrical and thermal contact resistances, measured at the interfaces with the Usibor®1500 sheet, are due to the Alusi® coating and are at the origin of the strong initial heating at these interfaces. A numerical model, limited to the electro- thermal aspects and developed with COMSOL Multiphysics®, shows that the nugget is initiated very quickly in Usibor®1500 sheet under the effect of adjacent contact resistances, and that its development is driven by the evolutions of the electrode-sheet contact areas. The contact resistances between the electrode and the thin sheet, the welding current evolution, and the curvature radius of electrode tips are the most efficient parameters to be optimized to improve the penetration of the nugget in the thin sheet
Le, Gloannec Brendan. "Modifications microstructurales sous sollicitations thermomécaniques sévères : application au soudage par résistance des gaines de combustibles en aciers ODS". Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0367/document.
Texto completo da fonteOxide dispersion strengthened (ODS) steels are considered as candidate materials for thedevelopment of fuel cladding for sodium-cooled fast reactors (SFR). Resistance upset welding of thecladding is studied in this work. The aim is to determine and to understand the process effects on themicrostructure of ODS steels with 9% and 14% of chromium at the scales of the grains and thenanometric oxides. An approach coupling microstructural characterization of welds, numericalsimulation and physical simulation of the process, using a thermomechanical simulator Gleeble 3500,is proposed. Resistance welding locally imposes severe thermomechanical conditions in terms of strain,strain rate and temperature. Refinement of the microstructure is noted and correspond to a dynamicrecrystallization mechanism (14 % Cr steel) or the combination of dynamic recrystallization and phasetransformations (9 % Cr steel). The conditions of occurrence of dynamic recrystallization are studied.The possibility of a transition between continuous and discontinuous dynamic recrystallization is shownfor the 14 % Cr steel according to the loading conditions. Such severe thermomechanical conditionsinduce an increase in the size of nanoscale oxides associated with a decrease of their volume fraction
Ben, Souda Souad. "Étude du comportement à la rupture de points de soudure par résistance sur tôles en acier extra doux et en acier biphasé". Compiègne, 1986. http://www.theses.fr/1986COMPE055.
Texto completo da fonteRossillon, Frédérique. "Influence des conditions de soudage sur le comportement en fatigue d'un acier THR Dual Phase soudé par point". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2007. http://tel.archives-ouvertes.fr/tel-00279069.
Texto completo da fonteRossillon, Frédérique. "Influence des conditions de soudage sur le comportement en fatigue d'un acier THR Dual Phase soudé par point". Phd thesis, Clermont-Ferrand 2, 2007. http://www.theses.fr/2007CLF21787.
Texto completo da fonteHuin, Thibaut. "Experimental and numerical investigation of the mechanical behaviour of dissimilar arc and spot welds of advanced high strength steels". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEI055/document.
Texto completo da fonteNowadays, ecological policy encourages carmakers to reduce the global vehicle weight. Fine steel sheets assemblies with different thickness optimizing each part of the assembly are used and steelmakers develop steels which are more and more resistant namely Advanced High Strength Steel (AHSS) with a good compromise between mechanical strength and ductility (stamping). During the mechanical tests of heterogeneous AHSS welding, unusual fracture modes are observed, in particular along the interface between the Heat Affected Zone (HAZ) and the Fusion Zone or molten zone (FZ). These fractures generally occur with lower strength than expected for these welding. The objectives of the study are to understand fracture mechanisms during mechanical testing and create a mechanical FE model is developed to be able to predict mechanical strength of the welded assemblies. Firstly, a study of heterogeneous welding constituted of two well-known steel grades of ArcelorMittal aims at understanding failure mechanism and parameters affecting the failure modes. Different configurations are studied with thickness. FE model is built with mechanical response identified of each zone (base materials, heat affected zones and fusion zone), using ArcelorMittal models and experimental data. Failure criteria based on ductile damage taking into account the influence of the triaxiality are used and some cohesive elements are used to simulate interfacial failure. Two configurations of mechanical testing in the case of Resistance Spot Welding (cross tension and tensile shear tests) are considered. Model predictions were very accurate with experimental failure modes and strengths. Then, this FE modelling method was successfully applied to a highly heterogeneous spot welding case including a new third generation low density AHSS concept with high aluminum and manganese content. Failure modes and strengths obtained were comparable. Moreover, FE modelling method was applied on more complex configurations, in particular on a triple thick spot welded assembly. The robustness of the model to predict partial failure modes and strengths of a triple thick spot weld has been demonstrated. In addition, FE modelling methodology was extended to another welding type: arc welding. In this case, two sheets are welded in ab overlap configuration with a filler wire. FE model allows predicting the failure zone and strength of welded assembly
Slimani, Ali. "Développement d'une méthodologie de caractérisation à haute température des alliages métalliques par micro-indentation". Compiègne, 2012. http://www.theses.fr/2012COMP2001.
Texto completo da fonteIndentation technique has been used extensively to measure the elastic modulus and hardness of materials. Lt has been instrumented and used successfully to identify other mechanical properties at room temperature. However the extension of this technique for characterization at high temperature is in its beginning. The main goal of my thesis is to characterize cast aluminum alloys using microindentation test at different temperatures. Ln addition to the quantities measured directly from indentation test such as Young modulus and hardness, we also determined the characteristic parameters like work hardening and viscoplasticity parameters at different temperatures. Ln this work, the high temperature indentation tests are combined with inverse analysis to calibrate the constitutive model parameters. Welding is one of the most important metal-joining processes used in diverse industries. However, the very concentrated heat in fusion welding, leads to a local dilatation and metallurgical phase transformation that generate inhomogeneous plastic deformation and residual stresses in the welded parts which can be a source of cracking and fracture problems in welded structures. Ln this study we use the micro indentation technique at different temperature which is a powerful tool to characterise the mechanical properties of a welded bond. The aim of this part is to characterize the differences of the mechanical properties of the different zones of the weld
Chtourou, Rim. "Tenue mécanique des assemblages soudés par point multi-tôles et acier multigrades : étude expérimentale, modélisation macroscopique et procédure d'identification". Thesis, Valenciennes, 2017. http://www.theses.fr/2017VALE0017/document.
Texto completo da fonteResistance spot welding (RSW) is widely used in the automotive industry. However, the prediction of their non-linear mechanical behavior and their failure in structural crashworthiness computations remains a challenge. The introduction of a new generation ofmulti-sheet multi-steel grade spot welded assemblies makes the prediction of their mechanical strength more complex.Despite the increasing use of these assemblies, the experimental study of their mechanical behavior is still very limited, while their macroscopic modeling has not yet been studied. An experimental device based on Arcan principle is thus proposed to characterize the mechanical strength and the failure of three-sheet spot welded assemblies, in pure and combined loads for different loading configurations. A macroscopic modeling approach is also proposed to simulate their mechanical behavior for structural applications. As a first step, a ’connector’ element is proposed, identified and validated for a two-sheet spot welded assembly. Then, a modeling approach using three connectors is proposed to simulate the mechanical behavior and the rupture of a three-sheet multi- steel grade spot welded assembly. An identification methodology is also presented to simplify the identification procedure of the model parameters. The model is identified and validated based on the experimental results of the Arcan tests carried out during this thesis
Mahelle, Pierre. "Caractérisation expérimentale et numérique du comportement d'assemblages soudés soumis à des sollicitations quasi-statiques et dynamiques". Valenciennes, 2007. http://ged.univ-valenciennes.fr/nuxeo/site/esupversions/f32d6052-7ffa-4abc-8874-e306547dd985.
Texto completo da fonteWhen subjecting a metallic structure to an impact or a crash, two kinds of fracture can be seen to appear jointly: rupture initiated in the sheet and rupture located on the joint areas. Depending on the type of transportation mean and materials used for the design of the vehicles, structures can be assembled either by rivets, spotwelds or weld beads. To prevent the failure of these joints, which can lead to a complete and particularly brutal structural disarticulation, their behaviour must be studied. The aims of this work are to measure the response of a spotwelded joint under quasi-static and dynamic loadings, to determine the load velocity influence on its behaviour, to understand how and where the failure starts and propagates in the assembly. Original tests, which make it possible to mix loading directions and to control the boundary conditions around the spotweld and the deformation of the metal sheet, were developed and performed under quasi-static and dynamic loadings on an hydraulic jack in a range of velocities from 5mm/mn to 1m/s. A new device was also developed to test spotwelds in pure tensile direction on SHB. This device uses SHB in a no-direct tensile testing configuration and a velocity of 13 m/s is reached. Load-displacement responses, failure mechanisms and topographies were obtained. To complete experiments, a fine numerical model of the spotweld was performed. The elastoplastic properties of the HAZ were experimentaly identified using some materials having undergone heat treatments. This model allows us to understand where the deformations are located
Vaziri, Mojgan. "Water Resistance of Scots Pine Joints Produced by Linear Friction Welding". Thesis, Nancy 1, 2011. http://www.theses.fr/2011NAN10059/document.
Texto completo da fonteWood welding is a mechanical friction process allowing the assembly of timber without any adhesives. The process consists of applying mechanical friction, under pressure, alternately to the two wood surfaces to be welded. This process can be applied to weld two flat pieces of timber, originating from the same or different tree species, and can be used in the manufacture of furniture and wood joinery. The only limitation is that the joint is not exterior-grade, but only suitable for interior joints. Exterior use, or use in an environment with varying humidity demands water resistance of the welded joints. The main objective of this thesis is to study the water resistance of the welded wood. This is complemented with special attention to non-destructive test methods such as X-ray Computed Tomography (CT-) scanning and Magnetic Resolution Imaging (MRI). The influence of welding parameters and wood properties on crack formation and crack propagation in the weldline was investigated. The influence of these parameters on weldline density and water absorption in the weldline were also studied. Investigations in this thesis are based on welded samples of Scots pine (Pinus sylvestris) of the dimensions 200 mm × 20 mm × 40 mm which were cut in the longitudinal direction of the wood grain. The tensile-shear strength of the welded Scots pine samples were determined using European standard EN 205. Different non-destructive methods such as X-ray Computed Tomography (CT-) scanning to study crack formation and propagation, and magnetic Resolution Imaging (MRI) to characterize water penetration and the distribution mechanism in welded wood were used. Solid state CPMAS 13C NMR spectrometry and X-ray microdensitometry investigations were carried out to study the mechanism of adhesion in Scots pine. These various non-destructive methods offer the advantage of non-invasive analysis and the elimination of any artifacts present due to preparation and sectioning. The most important results are summarized as follows: (1) X-ray Computed Tomography (CT-) scanning and Magnetic Resolution Imaging (MRI) are versatile research methods applicable to investigations of welded woods. (2) Water resistance of welded Scots pine can be increased using heartwood, a welding pressure of 1.3 MPa, and a welding time of 1.5 s. (3) Optimization tests showed that the tensile-shear strength of Scots pine was more sensitive to welding time changes than holding time and could be optimized to more than 9.7 MPa using 1.3 MPa welding pressure, > 3.5 s welding time, and < 60 s holding time. (4) Changing welding parameters and wood properties can increase water resistance of welded wood to some extent, but treating the weldline with certain natural and environmentally-friendly water repellents is still necessary. (5) Welded Scots pine shows unusually high water resistance and tensile-shear strength. This may be explained by there being more extractives compounds in Scots pine. (6) MRI experiments showed that the origin of the joint failure in welded beech is poor water resistance of the weldline, while swelling and shrinkage of wood are the main reasons for joint failure of welded Scots pine. (7) Extractives in Scots pine dramatically improve water resistance of the welded joint, but not to a level to classify the joint as an unprotected exterior grade. However, it can qualify as a joint for protected semi-exterior application