Tesis sobre el tema "Jauges de contrainte – Simulation par ordinateur"
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Ahmidayi, Najat. "Déformations de systèmes plasmoniques : application aux nanocapteurs de déformations". Electronic Thesis or Diss., Université de Lille (2022-....), 2024. http://www.theses.fr/2024ULILN022.
Texto completoBased on the exploitation of the optical properties of metallic nanoparticles in combination with flexible materials, plasmonomechanics has recently emerged as a subfield of nano-optomechanics. Plasmonomechanical systems, which enable the measurement of mechanical strains applied to flexible substrates through the plasmonic response of nanostructures, have attracted much attention in the scientific research community due to their potential applications, notably in strain detectors.Understanding the microscopic mechanical response to macroscopic deformation is a foundation of plasmonomechanics, essential for comprehending the optical response of nanostructures and its evolution. The first objective of this thesis is to understand, through numerical simulation tools, the mechanical and plasmonic responses, and more precisely, how interparticle distances evolve at the nanometric scale when macroscopic mechanical strain is imposed and influence the plasmonic response of the system. This will be studied through simple plasmonomechanical systems composed of gold nanodimers deposited on a PDMS membrane.Another challenge in this field is the design of plasmonomechanical systems with high sensitivity to mechanical deformations. This can be achieved through plasmonic systems supporting resonance modes with minimal losses (narrow linewidth). Thus, the second objective of this thesis is to realize plasmonomechanical systems supporting resonances such as the Fano resonance in a rod-disk system and the surface lattice resonance in a 2D array of gold nanorings, both known for their sharp and narrow resonance profiles
Seck, Babacar. "Optimisation stochastique sous contrainte de risque et fonctions d'utilité". Phd thesis, Ecole des Ponts ParisTech, 2008. http://pastel.archives-ouvertes.fr/pastel-00004576.
Texto completoWen, Youhai. "Approche micromécanique et simulation numérique par éléments finis de la transformation martensitique sous contrainte". Vandoeuvre-les-Nancy, INPL, 1997. http://www.theses.fr/1997INPL029N.
Texto completoMaria, Maxime. "Partition spatiale contrainte et convexe pour la simulation basée rayons". Thesis, Poitiers, 2016. http://www.theses.fr/2016POIT2292/document.
Texto completoRay-based methods are known to simulate accurately acoustic, thermic, radios or optic wave propagation phenomena. The efficiency of such a method lies in its capacity to quickly determine the closest intersection between a ray and the geometric primitives making up the simulation environment. Generally, an acceleration structure is used to reduce the algorithmic complexity of the search. These last thirty years, a lot of efficient structures have been proposed. However, all have drawbacks according to the application kind and the scene configuration. We propose to explore a way slightly studied up to then, using a constrained convex space partition (CCSP) as an acceleration structure. This kind of partition differs from conventional structures by several concepts bringing unique and interesting properties. In a first phase, we propose a new acceleration structure, based on a CCSP, specifically dedicated to simulation in architectural environments. Then, we used these results to generalize the approach to any kind of scene. In particular, we focus on the use of a constrained Delaunay tetrahedralization as an acceleration structure and propose a new traversal algorithm
Nguyen, Hoai Nam. "Étude numérique de la fissuration d'un milieu viscoélastique : analyse de l'essai de rupture sur bitume". Phd thesis, Ecole des Ponts ParisTech, 2008. http://pastel.archives-ouvertes.fr/pastel-00005307.
Texto completoPolitano, Olivier. "Simulations mésoscopiques de la déformation plastique des monocristaux C. F. C. Sous contrainte". Dijon, 1999. http://www.theses.fr/1999DIJOS066.
Texto completoLacorre, Philippe. "La frustration magnétique : quelques manifestations expérimentales, leur simulation et une approche théorique". Le Mans, 1988. http://www.theses.fr/1988LEMA1010.
Texto completoThe frustration problem is considered successively from the experimental point of view, by numerical simulation, then theoretically. The magnetic structures of a few fluorides of 3d cations ate solved from neutron powder diffraction and analysed in term of magnetic frustration. When spins are isotropic and coupling constants have about the same strength, the magnetic structure is non collinear (KCrF4, KMnFeF6). If spins are very anisotropic, or if coupling constants are rather different, the magnetic structure is collinear, and the weakest interaction is broken (CsCoF4, Ba2Ni3F10). In other compounds, we were not able to confirm frustration : either it is improbable (BaMnFeF7), or the coupling mechanisms are still unknown (Cr2F5). A computer program to simulate magnetic structures is presented : the program MCMAG. Based upon a heuristic method for optimisation (simulated anneaIing, applied to the algorithm of Metropolis), this program is designed to determine the ground-state configurationof a system of spins in interaction. The topology of the magnetic network is given by the user which makes it possible to simulate complex magnetic systems such as those encountered in many frustrated compounds. The magnetic structures of several frustrated fluorides, e. G. Those investigated in the first part of this work, have been successfully simulated from reasonable assumptions on coupling constants. For some compounds, the thermal behaviour of their magnetic structure and their evolution under an applied magnetic field have also been reproduced, at least qualitatively. A method to measure the constraint rate inside frustrated magnetic structures is presented. Within this cIassical approach, the constraint function of a magnetic system in interaction is defined as the opposite of the ratio between the coupling energy of the system and the "virtual" coupling energy it would have if all interactions were satisfied. This intensive parameter, that belongs to the range [-1,+1], can be used as a scale for frustration in magnetic systems. In this description, frustration can have two origins : an intrinsic origin, when interactions only compete, or an extrinsic origin, when magnetic constraint is caused by parameters external to exchange (magnetic field, anisotropy,. . . ). Simulations have been carried out on two families of classical frustrated systems ; they show that high extrinsic constraint rates may be associated with fluctuations (non-null entropy at T = 0). The (classical) value of the constraint rate of two frustrated periodic lattices is tentatively related to the large quantum effects, associated with frustration, which are observed in these systems. It is suggested that the "frustration rate", as defined from the constraint function, could be connected to some physical properties of frustrated systems
Nechnech, Ammar. "Modélisation numérique du problème du surcarottage : influence de la loi de comportement de la roche". Vandoeuvre-les-Nancy, INPL, 1998. http://docnum.univ-lorraine.fr/public/INPL_T_1998_NECHNECH_A.pdf.
Texto completoCaillet, Nicolas. "Prise en compte des spécificités des pièces forgées en fatigue illimitée". Phd thesis, École Nationale Supérieure des Mines de Paris, 2007. http://tel.archives-ouvertes.fr/tel-00271401.
Texto completoNguyen, Quoc Hoang. "Étude numérique de l’interaction d’un atome de carbone avec la dislocation vis dans le fer". Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10164.
Texto completoCarbon is one of the most frequent foreign interstitial atoms in the iron matrix, The presence of even a very little amount of these impurities can have a drastic inl1uence on the steel properties, It is well know that the strong interaction between interstitial solute carbon atoms and dislocations drive many mechanical properties of steels, ln partieular, it has important effects on the yield stress and is responsible of mechanical instabilities observed during the static strain ageing, which implies the formation of Cottrell atmosphere (Lüders' band), and the dynamic strain ageing, which occurs generally at high temperature and involves a competitive motion of dislocations and interstitial atoms (Portevin - Le Chatelier effect). This thesis work aims at characterizing the interaction between an interstitial carbon atom and a dislocation by means of numerical simulations at the atomistic scale. Since the properties of dislocations in body-centered cubic iron rely mainly on the dislocation core structure which depends on the interatomic potential used, this work has been carried out with a newly designed empirical potential which describes correctly the non degenerated screw dislocation core structure, as predicted by ab initio calculations. ln a first part, molecular statics has been used to determine the binding energy between the screw dislocation and a carbon atom, placed in different positions, ln a second part, dynamical simulations have been performed by applying a constant shear strain to the simulation box which makes the dislocation move on its gliding plane, ln the course of these simulations, 3 types of behaviour were observed, When the dislocation arrives close to the carbon atom, it can keep moving on its plane, ln a second scenario, the dislocation changes of slip plane, this is a typical exemple of cross slip. ln the 3rd type of behaviour, it is the carbon atom which moves when the dislocation is too close to it. It can jump to an adjacent octahedral site of the same plane or move onto another plane, The kind of behaviour observed depends on the local structure of the dislocation core in the vinicity of the carbon atom which intluence can be felt only lor short interaction distances. The simulations carried out in the frameworks of this thesis, are part of a multiscale modeling approach, which aims at predicting the evolution of material properties, based on the knowledge of the atomic structure and properties of elementar processes, i,e, processeses occuring at the atomic level
Heyrendt, Laurent. "Études des actions des forces magnétiques volumiques créées par un champ magnétique intense sur des fluides à seuil - possibilités de transition solide-gel". Phd thesis, Université de Lorraine, 2012. http://tel.archives-ouvertes.fr/tel-00799586.
Texto completoHeyrendt, Laurent. "Études des actions des forces magnétiques volumiques créées par un champ magnétique intense sur des fluides à seuil - possibilités de transition solide-gel". Electronic Thesis or Diss., Université de Lorraine, 2012. http://www.theses.fr/2012LORR0224.
Texto completoYield stress fluids have amazing mechanical properties: below a particular shear stress, called yield stress, the fluid behaves like a solid. Once the yield stress is exceeded, they flow like a viscous fluid or a gel. This thesis deals with the effects of magnetic volume forces on these fluids. We study the opportunity of the solid-gel transition from magnetic volume forces created by various magnetic devices. These fluids have no special magnetic properties. It is therefore necessary to create intense magnetic fields to act without contact on these fluids. We study different magnetic configurations that are able to exceed the yield stress in the fluid. The influences of different parameters of the magnetic configurations is explored, including using parametric studies. Our work combine equations of magnetostatic and non-newtonian fluid mechanics. Magnetostatic calculations are carried out analytically, while the mechanical and magneto-mechanical coupling are processed by a finite element analysis software. Magnetic and mechanical conditions required to the solid-gel transition and to the modification of yield stress fluids flows are discussed, using numerical simulations and dimensionless numbers
Kayad, Moussa Ahmed. "Influence de la température sur l'activité micro-sismique dans un réservoir fracturé lors d'injections de longue durée. Application aux données du site de Rosemanowes (UK). Première approche d'un site potentiel dans le rift d'Assal (Djibouti)". Electronic Thesis or Diss., Paris, ENMP, 2013. http://www.theses.fr/2013ENMP0084.
Texto completoThe general framework of our research deals with the development of geothermal energy for electricity production using the heat stored in geological formations at depths ranging in 3 to 5 km, Generally the environment is poorly permeable and fractured. Our main objective is to study the phenomenon of induced micro-earthquakes in relation to the cooling of the rock. The work is based on field experiences including long duration tests, conducted on the Rosemanowes site (Cornwall, UK). For this, we proceeded to the development of a calculation tool, FRACAS, able to simulate this phenomenon by introducing a dual thermal approach to better simulate the cooling of the reservoir due to long term fluid injections, which might be responsible for new failure mechanisms due to the induced tractions. In this context, we introduced a new algorithm to describe shear in stabilities, a mechanism of "stick-slip" type with the consideration of static/dynamic friction coefficients. The possibility of inducing micro-seismicity is then studied using the in situ data base, with two 3D models offering different geometric approaches, a deterministic model and a stochastic model whose geometrical and physical properties were obtained from observations and previous work on this Rosemanowes site. The Thermo-Hydro-Mechanical (THM) simulation using the deterministic model has allowed us to calibrate the transient heat transfer in the reservoir formed by the drilling system RH12/RH15 and to give an estimate of tensile stress of thermal origin. To better study the effect induced by the contraction of the rock during time, we use the stochastic 3D model whose main objective is to simulate a more realistic spatial migration of shear ruptures. With this model we found a delayed onset of shear activity and discuss the effect of pressure step tests. The results suggest a way to mitigate the potential impact of shear ruptures due to cooling
Van, Belle Laurent. "Analyse, modélisation et simulation de l'apparition de contraintes en fusion laser métallique". Thesis, Lyon, INSA, 2013. http://www.theses.fr/2013ISAL0116/document.
Texto completoThe Selective Laser Melting process, belonging to Additive processes , have the ability to create structures with complex geometries , with the possibility of including cavities, such as cooling channels providing optimum temperature control. This process enables the manufacture of three-dimensional parts from metal powders by melting the material , layer by layer, in agreement with the CAD model. In the process , high temperatures and thermal gradients cycles occur in the part during the process. These temperature gradients induce heterogeneous plastic strain and residual stresses. These residual stresses may affect the quality of the part obtained, for example the fatigue life. This work aims to propose a numerical model , based on the finite element method to study the appearance of residual stresses during laser melting process of metallic powders . The ABAQUS® Multiphysics software was used to perform the thermal and mechanical analyzes. The movement of the laser beam and the resolution of the thermal problem can predict the evolution of the temperature in the part and support. The "birth and death elements" technique was used to simulate the melting and solidification of the material during the process. Dependent mechanical properties of the temperature of the maraging steel used in this case were obtained using experimental testing and characterization and were established in the model. The calculations are decoupled : initially thermal calculation is performed and the results are used to perform mechanical calculations and finally predict the residual stress fields. In this work, a novel method based on the technique of measuring residual stresses by removing layers was developed to measure these stresses directly in the process. The results provide information on the level and distribution of stresses in the created part and support. Two parameters were tested to study their influence on the level of residual stress : time to spread the powder between two successive layers and layer height. The model is used to analyze the effects of process parameters related to the distribution of residual stresses in the manufactured parts. The results show that the variation of the thickness of the support does not affect the distribution of stresses in the part created. Preheating the substrate to a temperature of 800 °C reduces the residual stresses. The study of some laser strategies shows their influence on the distribution of plastic strain thus the height of the layers of powder or in the form of support (base, columns)
Ghazavizadeh, Akbar. "Modeling and simulation of the micromechanical behavior of semi-crystalline polyethylene including the effect of interphase layer". Thesis, Strasbourg, 2013. http://www.theses.fr/2013STRAD048/document.
Texto completoElastic characterization of the interphase layer in polyethylene is implemented by applying the relationships of two micromechanical approaches, “Extended Composite Inclusion Model” and “Double-Inclusion Method”, to the Monte Carlo molecular simulation data for the interlamellar domain. The results of the two approaches match perfectly. The interphase stiffness lacks the common feature of positive definiteness, which indicates its mechanical instability. Comparison with experimental results endorses the proposed methodology. For the hyperelastic characterization of the interlamellar domain and the interphase layer, the proposed hybrid algorithm consists in applying the constitutive equations of an isotropic, compressible, hyperelastic continuum to the molecular dynamics simulation results of a polyethylene stack. Evolution of the interphase boundaries are introduced as auxiliary variables and the notion of minimizing a set of nonnegative objective functions is employed for parameter identification. The identified hyperelastic parameters for the interlamellar domain arein good agreement with the ones that have been estimated experimentally. Finally, the large, viscoplastic deformation of an aggregate of polyethylene is reexamined. The Gent model adopted for the back stress of the noncrystalline phase, correcting the projection tensor for the modified Taylor approach, and the idea of multilevel optimization are among the contributions made
Sadeghi, Rezvan. "Consistency of global and local scheduling decisions in semiconductor manufacturing". Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEM023.
Texto completoThe operational level in semiconductor manufacturing can be divided into a global level and a local level. The global level refers to the scheduling decisions and production control for the whole manufacturing facility (fab), while the local level deals with those issues in each work area. The global level provides objectives or constraints for the local level. In this thesis, we propose a general framework which aims at supporting and controlling the decisions taken at the local level to deal with consistency problems between global and local scheduling decisions. The framework is composed of two layers. The bottom layer includes local policies used in each work center. The top layer consists of global objectives, global information and a global strategy which is the core of this framework. The proposed global strategy aims at controlling local policies as well as production processes. The idea is to periodically run the global strategy while production is performed to guide the production process towards achieving global objectives, and thus ensuring consistency between decisions taken at the global and local levels. We propose two types of global strategy: (1) An evaluation-based strategy which aims at improving the production process with no guarantee to determine an optimal solution and (2) An optimization-based strategy, based on a Linear Programming model. In order to evaluate the performance of the proposed framework, we develop a data-driven generic simulation model for semiconductor manufacturing facilities. The simulation model is a combination of Agent-Based and Discrete Event modelling methods developed with the software AnyLogic. Since the standard solver IBM ILOG CPLEX is used to solve the linear programming model, we describe its integration with AnyLogic. A set of experiments on industrial instances are presented and discussed. In addition, this thesis deals with the management of time constraints. In a semiconductor manufacturing facility, time constraints are associated to two process steps to ensure the yield and quality of lots. A time constraint corresponds to a maximum time that a lot can spend between the two steps. If a time constraint is not satisfied by a lot, this lot will be scrapped or reprocessed. Therefore, because manufacturing equipment is expensive and cycle times must be minimized, efficiently controlling the start of lots in time constraints is important. We propose an approach which estimates the probability of satisfying a time constraint before starting a lot in the first step of the time constraint. This approach was implemented and validated on industrial constraints
Duong, Vu Nguyen. "La résolution des réseaux de contraintes algébriques et qualitatives : une approche d'aide à la conception en ingéniérie". Phd thesis, Ecole Nationale des Ponts et Chaussées, 1990. http://tel.archives-ouvertes.fr/tel-00520680.
Texto completoBouaou, Kevin. "Apport de la mécanique des fluides dans l'étude des flux sanguins aortiques". Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS076.
Texto completoAging is associated with morphological, functional and hemodynamic changes in the arterial system, most often aggravated by cardiovascular disease. Understanding these aggravating interactions is important to reduce patients risk. Medical imaging plays a major role in this context through modalities such as velocity encoding MRI combined with quantitative image processing and computational resolution of Navier-Stokes equations that govern blood flow hemodynamics. The aim of this thesis is to develop and combine image processing methods dedicated to 4D flow MRI data analysis with computational fluid dynamics to extract quantitative biomarkers such as intra-aortic pressure fields and their spatio-temporal propagations, aortic wall shear stress and intra-aortic vorticity. We have demonstrated the ability of these biomarkers to detect age-related sub-clinical aortic impairment and to characterize pathological aortic dilatation. In addition, association of spatio-temporal aortic pressure distributions with vortex occurrence and duration as well as with wall shear stress were studied. In a second work, we developed a numerical simulation software to solve the Navier-Stokes system using finite element models. An iterative projection method was applied to 2D and 3D vessel stenosis models as well as to 3D geometrical aortic models resulting from segmentation to validate our implementation. Finally, a preliminary work applying our numerical model to patient-specific geometries was performed revealing encouraging associations between simulated data and MRI measures
Gomes, De Figueiredo Bruno. "Integration of in situ stress measurements in a non-elastic rock mass". Thesis, Strasbourg, 2013. http://www.theses.fr/2013STRAH022/document.
Texto completoA case study is considered in which data produced by different techniques have been gathered in various locations within a rock mass in which topography effects are most likely significant. Measurements were performed for the design of a re-powering scheme that includes a new hydraulic conduit and an underground cavern that will primarily be excavated in granite. An integrated approach for extrapolating the results from the various in situ tests to the rock mass volume of interest for the hydroelectric power scheme is presented. This approach includes the development of an equivalent continuum mechanics model. The integration of in situ tests and numerical modelling enables to determine the stress spatial variation which helps ascertain the loading mechanism at the origin of the measured stress field as well as the long-term rheological behavior of the equivalent geomaterial under consideration
Guellec, Corentin. "Caractérisation en fatigue à grand nombre de cycles par mesures d’auto-échauffement des aciers d’arbres de transmission pour application navale sous chargements cycliques complexes". Electronic Thesis or Diss., Brest, École nationale supérieure de techniques avancées Bretagne, 2023. http://www.theses.fr/2023ENTA0001.
Texto completoMarine shaft lines undergo complex cyclic loadings. In order to characterize these structures in fatigue, two complementary objectives are achieved. Firstly, the marine shaft’s loads are characterized in order to identify relevant fatigue cycles. During this step, an original parametric fatigue design method is implemented. This method is based on the definition of an equivalent load considering multiaxiality, variability, non-proportionality and mean stress. This method allows to distinguish two damage modes with a mode associated with the established cyclic regime of rotary bending and a mode associated with the ship’s maneuvers. Secondly, a rapid characterization method is implemented to characterize in fatigue the marine shafts’ steels for a large number of loading configurations. The method is based on a model which enables fatigue identification behaviors from self-heating measurements. The steels of the study are characterized in tension-torsion for various configurations of mean stress and nonproportionality of the loading. In this context, the notion of iso-self-heating surfaces is introduced. It allows, for a specimen, to model the elastoplastic and dissipative behavior of the material in the dedicated stress space. Their use makes it possible to define a multiscale fatigue criterion based on the invariants of the stress tensor. In the study, a modeling of the behavior of the material is proposed for very low amplitude loads (VHCF) exhibiting a strong difference in dissipation compared to the regime of higher amplitudes (i.e. HCF domain)
Kayad, Moussa Ahmed. "Influence de la température sur l'activité micro-sismique dans un réservoir fracturé lors d'injections de longue durée. Application aux données du site de Rosemanowes (UK). Première approche d'un site potentiel dans le rift d'Assal (Djibouti)". Thesis, Paris, ENMP, 2013. http://www.theses.fr/2013ENMP0084/document.
Texto completoThe general framework of our research deals with the development of geothermal energy for electricity production using the heat stored in geological formations at depths ranging in 3 to 5 km, Generally the environment is poorly permeable and fractured. Our main objective is to study the phenomenon of induced micro-earthquakes in relation to the cooling of the rock. The work is based on field experiences including long duration tests, conducted on the Rosemanowes site (Cornwall, UK). For this, we proceeded to the development of a calculation tool, FRACAS, able to simulate this phenomenon by introducing a dual thermal approach to better simulate the cooling of the reservoir due to long term fluid injections, which might be responsible for new failure mechanisms due to the induced tractions. In this context, we introduced a new algorithm to describe shear in stabilities, a mechanism of "stick-slip" type with the consideration of static/dynamic friction coefficients. The possibility of inducing micro-seismicity is then studied using the in situ data base, with two 3D models offering different geometric approaches, a deterministic model and a stochastic model whose geometrical and physical properties were obtained from observations and previous work on this Rosemanowes site. The Thermo-Hydro-Mechanical (THM) simulation using the deterministic model has allowed us to calibrate the transient heat transfer in the reservoir formed by the drilling system RH12/RH15 and to give an estimate of tensile stress of thermal origin. To better study the effect induced by the contraction of the rock during time, we use the stochastic 3D model whose main objective is to simulate a more realistic spatial migration of shear ruptures. With this model we found a delayed onset of shear activity and discuss the effect of pressure step tests. The results suggest a way to mitigate the potential impact of shear ruptures due to cooling
Mondelin, Alexandre. "Modélisation de l'intégrité des surfaces usinées : Application au cas du tournage finition de l'acier inoxydable 15-5PH". Phd thesis, Ecole Centrale de Lyon, 2012. http://tel.archives-ouvertes.fr/tel-00838512.
Texto completoMarchandon, Mathilde. "Vers la compréhension des séquences sismiques sur un système de failles : de l’observation spatiale à la modélisation numérique. Application à la séquence du Nord-Est Lut, Iran". Thesis, Université Côte d'Azur (ComUE), 2018. http://www.theses.fr/2018AZUR4055/document.
Texto completoMany studies show that static and postseismic stress transfers play an important role in the occurrence of seismic sequences. However, a large majority of these studies involves seismic sequences that occurred within fault systems having simple geometric configurations (e.g. collinear or parallel fault system). In this thesis, we study a seismic sequence that occurred within a complex fault system (i.e. conjugate fault system), the NE Lut seismic sequence (1939-1997, NE Iran), in order to assess if (1) stress transfers can explain the succession of earthquakes in the sequence and (2) stress transfers can lead to the synchronization of the NE Lut faults over multiple seismic cycles. To this end, we first measure the surface displacement field produced by the sequence in order to precisely constrain the stress transfer modeling afterwards. We use optical correlation technique to measure the surface displacement fields of the Khuli-Boniabad (Mw 7.1, 1979) and Zirkuh earthquake (Mw 7.2, 1997). We find that these earthquakes broke several segments limited by geometrical complexities of the faults. We interpret the differences in failure style of these earthquakes (i.e. rupture length, mean slip and number of broken segments) as being due to different level of structural maturity of the Dasht-e-Bayaz and Abiz faults. Furthermore, we succeed to detect offsets produced by the 1979 Mw 6.6 Korizan earthquake. It is the first time that surface displacements for such a small historical earthquake have been measured using optical correlation. Then, combining previously published intermediate-field InSAR data and our near-field optical data, we estimate a new source model for the Zirkuh earthquake (Mw 7.2, 1997). We show that near-field data are crucial to better constrain the fault geometry and the slip distribution at depth. According to our source model, the Zirkuh earthquake broke three asperities separated by geometrical barriers where aftershocks are located. No shallow slip deficit is found for the overall rupture except on the central segment where it could be due to off-fault deformation in quaternary deposits. Finally, we use the information acquired in the first parts of this work to model the stress transfers within the NE Lut sequence. We find that 7 out of 11 earthquakes are triggered by the previous ones and that the precise modeling of the rupture geometry is crucial to robustly estimate the stress transfers. We also show that the Zirkuh earthquake is mainly triggered by the moderate earthquakes of the NE Lut sequence. Lastly, the simulation of multiple seismic cycles on the NE Lut fault system shows that stress transfers, in particular postseismic stress transfers due to viscoelastic relaxation, enhance the number of seismic sequences and synchronize the rupture of the faults. The simulations also show that the order in which the Mw>7 earthquakes occurred during the NE Lut sequence is quite exceptional
Pushparajalingam, Jegan Sutharsan. "Simulations expérimentale et numérique des phénomènes de ruissellement et d’atomisation lors d’une procédure de lavage à l’eau". Thesis, Toulouse, ISAE, 2012. http://www.theses.fr/2012ESAE0005/document.
Texto completoThis work has been realised within a CIFRE contract with TOTAL. Its aim was to validate all the physical models used in a computation, which simulates an annular dispersed flow through a pipe used in a water washing process in refinery plants. That is why, a whole set of data has been gathered using experimental boundary conditions which are representative to those used in industrial configurations. The geometry is made of a horizontal pipe with a centred nozzle followed by a 90º elbow in the vertical plane. Several experimental boundary conditions enable one to study the influence of the gas velocity, the type of the spray injection and the pressure on the different physical phenomena. These results including spray and liquid film visualisations, droplets distribution and size measurements as well as liquid film thickness and mass flow measurements were analysed in order to extract the main interaction mechanism between the gas and the dispersed phase, the gas and the liquid film, and the dispersed phase and the annular liquid film. Meanwhile, simulations using a RANS approach were realized with the ONERA code named CEDRE and its results were compared to the gathered measurements
Baccar, El Boubkari Fedia. "Évaluation des mécanismes de défaillance et de la fiabilité d’une nouvelle terminaison haute tension : approche expérimentale et modélisation associée". Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0266/document.
Texto completoThis work is a part of the research project SUPERSWITCH in which alternatives solutions to the IGBT, are investigated. This solution was used IGBT in power converters in the 600-1200 V breakdown voltage range. The new MOSFET structures based on the super-junction, such as the DT-SJMOSFET and its "Deep Trench Termination", is proposed as an alternative to IGBT. In this context, this thesis focuses on the robustness characterization of the DT2 termination adapted to a planar diode. After a state of the art on unidirectional voltage power components, the power components termination, and power modules reliability, a test vehicle has been designed in order to carry out different accelerated ageing tests and electrical monitoring. The reliability of DT2 termination was evaluated by experimental tests and numerical simulations. An innovative modeling methodology has been proposed. Finally, new structures have been proposed to limit the delamination failure mechanisms and interface charges problems highlighted in this thesis