Dissertationen zum Thema „Dynamique non-linéaire – Modèles mathématiques“
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Simoneau, Kevin. „Analyse non-linéaire du comportement dynamique des sols granulaires lâches“. Thesis, Université Laval, 2012. http://www.theses.ulaval.ca/2012/28164/28164.pdf.
Der volle Inhalt der QuelleSeck, Ousmane. „Sur un modèle de diffusion non linéaire en dynamique des populations“. Nancy 1, 1986. http://www.theses.fr/1986NAN10162.
Der volle Inhalt der QuelleViana, Serra Villa Cristiano. „Dynamique non linéaire des rotors : Applications numériques et expérimentales à un rotor flexible“. Ecully, Ecole centrale de Lyon, 2005. http://bibli.ec-lyon.fr/exl-doc/cvilla.pdf.
Der volle Inhalt der QuelleThis thesis deals with the dynamic behavior of rotating machinery containing the parts whose behavior is described by non linear laws. The first goal of this research is to implement methods of non linear analysis in order to solve the equations of motion of the system. Secondly, experimental studies are made with a test rig and the results are used to update a numeric model. The rotor is represented by a finite element model. To model the bearings, three models with different levels of complexity are presented, and a model where the kinematics of the rolling elements is adopted. The type of motion of interest is the steady state vibration, and to obtain this kind of solution it is advisable to use a frequential method like the Harmonic Balance Method Alternating Frequency Time (HBM AFT). This method can be implemented with an exact condensation strategy to reduce the computational time. The HBM AFT method is validated by comparing with a direct integration of a non linear Jeffcott rotor
Saez, Robert Esteban. „Interaction dynamique non-linéaire sol-structure“. Phd thesis, Ecole Centrale Paris, 2009. http://tel.archives-ouvertes.fr/tel-00453297.
Der volle Inhalt der QuelleAbbassi, Younès. „Contribution à la modélisation et à la commande de la dynamique du véhicule“. Besançon, 2007. http://www.theses.fr/2007BESA2015.
Der volle Inhalt der QuelleThe work presented deals with the problematic modeling and control of a vehicle dynamics by associating the theoretical studies and numerical simulation. The originality of the work consists to use the expressions of the different energies developed by the vehicle and the Raleigh dissipation function to obtain a global model of vehicle dynamics. This model is simplified in the aim to prupose the both linear and nonlinear controls. The first part of this work is dedicated to the modeling of vehicle dynamics by using the Lagrange formalism in its complete form. The obtained global model has 20 degrees of freedom and takes into account the different parts of the vehicle. The aim of the modeling is to provide a model capable to describe the nonlinear vehicle behavior in different and difficult situations such a braking or acceleration in a turn. The second part is devoted particularly to the problem of the synthesis of control laws for stabilization by feedback control and the follow-up trajectory. The considered models are those established in the first part. These models are nonlinear and the control strategies are pruposed by considering these nonlinearities and without any linearization
Khalil, Louay. „Influence de l’interaction sol-structure sur le comportement sismique des bâtiments : analyse dans les domaines linéaire et non linéaire“. Thesis, Lille 1, 2009. http://www.theses.fr/2009LIL10078/document.
Der volle Inhalt der QuelleThe thesis concerns analysis of the influence of the soil-foundation-structure interaction on the seismic on the seismic response of buildings. The study is carried out using the finite differences method of the system soil, foundation and structure.The thesis is composed of three parts.The first one concerns analysis of the influence of the soil-foundation-structure interaction on the fundamental frequency of building. The soil-foundation system is modeled using translational and rotational discrete springs. Analyses conducted for various soil and structure conditions showed that the building fundamental frequency depends on the soil-structure relative rigidity (Kss). A chart is proposed for an ease consideration of the influence of the SSI in the determination of the fundamental frequency of buildings.The second part deals with the analysis of the soil-foundation-structure interaction in the elastic domain. It shows that the response of the structure depends on the complex interaction between the soil and the structure. It also shows that the elastic nonlinear behavior of soil makes induces additional difficulties because of the apparition of multiple frequencies in the soil. The third chapter analyses the influence of the soil and structure nonlinearities on the seismic response of the system soil-foundation-structure. This study shows the plasticity of the soil and structural elements have a significant influence on the seismic response of the structure
Korkmaz, Ibrahim. „Contribution à l'analyse dynamique d'une aube soumise à un frottement sec“. Toulouse, ENSAE, 1993. http://www.theses.fr/1993ESAE0009.
Der volle Inhalt der QuelleLopez-Caballero, Fernando. „Influence du comportement non linéaire du sol sur les mouvements sismiques induits dans des géo-structures“. Châtenay-Malabry, Ecole centrale de Paris, 2003. http://www.theses.fr/2003ECAP0926.
Der volle Inhalt der QuelleBekhoucha, Ferhat. „Dynamique non linéaire des poutres en composite en mouvement de rotation“. Thesis, Lorient, 2015. http://www.theses.fr/2015LORIS389.
Der volle Inhalt der QuelleThe work presented in this manuscript is a contribution to the non-linear vibrations of the isotropic beams and composite rotating beams study. The mathematical model used is based on the intrinsic formulation and geometrically exact of Hodges, developped for beams subjected to large displacements and small deformations. The resolution is done in the frequency domain after a spatial-temporal dicretisation, by using the Galerkin approximation and the the harmonic balance method, with boundary conditions corresponding to the clamped-free. The final dynamic system is treated by continuation methods : asymptotic numerical method and the pseudo-arc length method, whose algorithms based on these continuation methods were developed and a convergence study was carried out. This study surround the aspects : statics, linear modal analysis, non-linear free vibrations and the non-linear forced vibrations of the rotating beams. These continuation algorithms were tested for the response curves calculations on cases elaborated in the literature. Internal resonance and the stability of the solutions obtained are studied
Yengui, Hédi. „Modélisation du comportement dynamique non linéaire d'un système machine - outil - pièce lors d'une opération de fraisage“. Phd thesis, Ecole Centrale Paris, 2011. http://tel.archives-ouvertes.fr/tel-00619636.
Der volle Inhalt der QuelleNahayo, Fulgence. „Modèle mathématique d'optimisation non-linéaire du bruit des avions commerciaux en approche sous contrainte énergétique“. Phd thesis, Université Claude Bernard - Lyon I, 2012. http://tel.archives-ouvertes.fr/tel-00855690.
Der volle Inhalt der QuelleRouss, Vicky. „Expérimentation en dynamique des systèmes mécaniques complexes pour le transport“. Besançon, 2008. http://www.theses.fr/2008BESA2008.
Der volle Inhalt der QuelleThis work was accomplished within the framework of FCLAB, national research institute for fuel cell systems, with for objective to develop, in an experimental approach, a procedure for identification complex mechanical systems as the recognition of their dynamical behaviour. Practically, this work contributes in modelling the mechanical behaviour of PEM fuel cells. The first part of this memo develops the subject of the thesis. It includes three sub-parts: a presentation of the test bench which includes the vibration platform of the UTBM, an introduction to the complex mechanical systems as well as their identification procedure and a description of the PEM fuel cells especially its nonlinear mechanical aspect. The procedure of identification of complex mechanical systems includes three stages which are going to define the parts two, three and four successively. The first stage is the realization of the vibration tests. For that purpose, a procedure for complex mechanical systems vibration tests is developed in the second part. This procedure is fundamental for the good progress and exploitation of the tests. The acquisition data are used for the two following stages. The second stage of the identification procedure, developed in the third part, consists in characterizing non-linearities from the experimental data. The characterization contains detection, classification and localization of non-linearities. The third and last stage of the identification procedure develops modelling the complex mechanical systems with neural networks. It explains the steps for creating a neuronal model. The neural networks are developed in the fourth part. To conclude this memo, the identification procedure of a complex mechanical system is applied to a PEM fuel cell. Results are exposes and discussed in the fifth part
Barbaroux, Jean-Marie. „Modèles mathématiques de la chimie quantique atomique & dynamique quantique et spectre multifractal“. Habilitation à diriger des recherches, Université de Nantes, 2005. http://tel.archives-ouvertes.fr/tel-00010385.
Der volle Inhalt der QuelleCarrier, Bruno. „Vers une modélisation des stratégies d'investissement multidimentionnel“. Paris 1, 1989. http://www.theses.fr/1989PA010023.
Der volle Inhalt der QuelleIhsan, Mohammad. „Analysis of the stability of slopes submitted to water infiltration using advanced models : coupled hydromechanical model and Nonlinear Dynamics Method“. Thesis, Lille 1, 2014. http://www.theses.fr/2014LIL10091/document.
Der volle Inhalt der QuelleThis research concerns analysis of landslides, which constitute a major natural risk responsible for high human losses as well as large damages to structures, infrastructure and natural environment. This issue becomes particularly important, because of the climate change, which increases the risk of heavy rains as well as severe drought and consequently the risk of slope instability due to the environment change. Generally, analysis of slope stability is conducted using the limit equilibrium theory. As this theory does not take into consideration the process of mobilization of the friction, it could lead to an overestimation of the safety factor. A reliable analysis of the slope stability, in particular in heterogeneous soils submitted to the water action, requires the use of advanced numerical methods. Two methods were used in this research: the coupled hydro-mechanical method and the nonlinear dynamic method
Duchereau, Jérôme. „Modélisation non paramétrique des incertitudes en dynamique transitoire des systèmes complexes avec incertitudes non homogènes“. Paris, CNAM, 2004. http://www.theses.fr/2004CNAM0479.
Der volle Inhalt der QuelleThis paper is devoted to numerical models for prediction of transient dynamical response induced by shocks upon structures with inhomogeneous random uncertainties. The usual numerical methods for analyzing such structures in the low- and medium- frequency ranges employ reduced matrix models based on the use of the elastic modes. The contribution of the higher modes is very sensitive to the modelling and data errors. Here, a recent nonparametric probabilistic method is applied to construct the random matrix model allowing modelling and data errors to be taken into account. The paper presents an extension of the nonparametric method for the case of inhomogeneous uncertainties in the structures. A dynamic substructuring method is used and every substructure gets its own uncertainty level. Experiments have been developed in order to validate the nonparametric probabilistic approach of random uncertainties for such dynamical systems
Pauzin, Marie-Christine. „Modélisation du comportement dynamique d'un agent de contraste ultrasonore“. Phd thesis, Université de Provence - Aix-Marseille I, 2009. http://tel.archives-ouvertes.fr/tel-00430076.
Der volle Inhalt der QuelleFouquet, Manon. „Commande prédictive non-linéaire. Application à la production d'énergie“. Thesis, CentraleSupélec, 2016. http://www.theses.fr/2016SUPL0003/document.
Der volle Inhalt der QuelleThis thesis deals with hybrid optimal control and Model Predictive Control (MPC) of power plants by use of physical models. Models of the facilities are developped with Modelica, an equation based language tailored for modelling multi-physics systems. Modeling of physical systems with Modelica is introduced in a first part, as well as some of the symbolic processing done by Modelica compilers that transform the original model to a form suited for optimization. Then, a method to solve optimal control problems on hybrid systems (such as power plants) is presented. This methods provides an optimal trajectory for the power plant on a long horizon. The optimal trajectory computed by the method includes the trajectories of continuous inputs as well as switching decisions for components in the plant. The optimization algorithm combines the collocation method and a method named Sum Up Rounding (SUR) for dealing with switches. Finally, a Model Predictive Controller is developped in order to follow this optimal trajectory in real time, and to cope with disturbances on the actual system and modelling errors. The proposed MPC uses tangent linear models of the plant that are derived automatically from the nonlinear model
Le, Maître Olivier P. „Contribution numérique à la résolution de problèmes d'interaction fluide-structure non linéaires“. Le Havre, 1998. http://www.theses.fr/1998LEHA0007.
Der volle Inhalt der QuelleGogu, Ada. „Dimensionnement des réseaux RCSF sous des contraintes énergétiques : modèles mathématiques et méthodes d'optimisation“. Compiègne, 2012. http://www.theses.fr/2012COMP2028.
Der volle Inhalt der QuelleIn this thesis, we focused on the development of optimal methods regarding WSN dimensioning problems, mostly encountered during the planning phase. These were instantiated basically into three combinatorial optimization problems. The network deployment scheme which seeks to place the sensors in a such way that the cost of communication operations is minimized. The network configuration problem that asks to find a strategy for dividing the network such that some criteria are satisfied. In the problem’s model we took into account the data aggregation constraint and the discrete values of power transmission. For both problems we proposed a resolution method, based on dynamic programming, which permitted us to solve them optimally. Finally, the joint problem of scheduling and power assignment, consisted in finding a feasible scheduling under SINR constraints and a power assignment scheme to guarantee successful concurrent transmissions. As the problem is shown to be NP-hard we propose a greedy heuristic. The resolution method for the power assignment strategy, an iterative algorithm based on linear programming, provides optimal solutions
Al, Moatassime Hassan. „Simulations numériques d'écoulements permanents de fluides non newtoniens par une méthode multigrille“. Paris 11, 1993. http://www.theses.fr/1993PA112472.
Der volle Inhalt der QuelleBenharbit, Saad. „Sur la théorie et l'approximation numérique des problèmes hyperboliques non linéaires :“. Phd thesis, Grenoble 1, 1992. http://tel.archives-ouvertes.fr/tel-00341589.
Der volle Inhalt der QuelleDion, Jean-Luc. „Modélisation et identification du comportement dynamique des liaisons hydro-élastiques“. Châtenay-Malabry, Ecole centrale de Paris, 1995. http://www.theses.fr/1995ECAP0412.
Der volle Inhalt der QuelleLadjimi, Mohamed Tahar. „Modélisation biophysique de la mort cellulaire en réponse au stress thermique“. Electronic Thesis or Diss., Université de Lille (2018-2021), 2019. http://www.theses.fr/2019LILUR029.
Der volle Inhalt der QuelleThe living cell is constantly exposed to various types of stress that can damage its components. When the induced damages are detected, defense mechanisms are activated to repair them while optimally managing the energy resources available and necessary for cell function. If the stress is too severe and the system can not defend itself, death will be inevitable. The cellular response to stress is orchestrated by intracellular signaling networks that are extraordinarily complex. The molecular species constituting these networks perform various tasks through biochemical reactions, forming synchronized biological process machineries. Our approach in this thesis for the study of these networks is to model them mathematically to reproduce an observed phenomenon and identify its key players, analyze their reactions in response to different signals, and possibly make precise enough and experimentally verifiable predictions that can be of an extreme utility for therapeutic applications. In our studies, we focus on thermal stress and on the resulting cellular response in terms of the dynamics of the molecular species involved, but also of cell fate (death or survival) at the end of the exposure, we adress those questions by dynamic models describing the biochemical kinetics of system variables as a consequence of temperature variation. In a first step, we demonstrate through simulations, followed by experimental validation, that the temporal form of heat stress significantly impacts cell survival. This first result highlights a mechanism of saturation of the repair species as a consequence of exposure to high temperatures. In a second step, we study the potential correlation between a variability introduced on the levels of two proteins in the heat shock response network and the phenomenon of fractional killing. According to our model predictions, experimentally measured chaperone proteins (repair species) variability alone is not sufficient to explain fractional killing, which must involve other sources of variability. Finally, an analysis of the isoeffect curves generated by a generic model of the cellular response to transient stress shows the existence of four sensitivity regimes depending on the duration-intensity parameters of the stress as well as on the parameters of the response network and its time scales. Our work highlights the potential and utility of dynamic network models in the characterization of dose-response curves
Maliwan, Kittinan. „Modélisation de l'action des vibrations sur les écoulements de convection thermique ou solutale en milieux poreux“. Toulouse 3, 2004. http://www.theses.fr/2004TOU30137.
Der volle Inhalt der QuelleThe present work, we study analytically the effect of the action of high-frequency vertical vibration on the onset of the convective motion in mono and multi-component fluids in porous media. The geometry considered is a "Rayleigh-Bénard" configuration. Generalized Darcy-Brinkman mathematical model is taken into account to describe convective flows. In the framework of Oberbeck-Boussinesq approximation, the induced convective motion due to temperature field or concentration field in the presence of gravitational and vibrational fields are studied by using time-averaged method. In the first part of this work, the case of porous media saturated by pure fluid is considered. The critical parameters are found by applying Galerkin method. The asymptotic analysis is also performed to obtain an analytical relation in the case of small Darcy numbers. It is shown that high-frequency vertical vibration can delay convective instabilities and, in this way, reduce the convective flow. In the case of very small Darcy numbers, the weakly non-linear analysis is then carried out to obtain an expression for Nusselt number. .
Jeambrun, Denis. „Propagation d'une onde de cisaillement en milieu non linéaire dissipatif“. Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 1995. http://tel.archives-ouvertes.fr/tel-00755781.
Der volle Inhalt der QuelleGuérin, Adrien. „Dynamique de l'écoulement dans un aquifère non confiné“. Sorbonne Paris Cité, 2015. https://hal.science/tel-01884762.
Der volle Inhalt der QuelleRiver hydrographs generally exhibit intense flood events during which the discharge increases quickly during rainfall, anc decreases slowly afterwards. In this manuscript, we show that the dynamics of groundwater in an unconfined aquifer can account for these features. In the frame of the Dupuit-Boussinesq (shallow-water) approximation, the discharge increase rate ˙Q is a non-linear fonction of the rainfall rate R : ˙Q ∝ R 3/2. After the rain, two consecutive asymptotic regimes compose the drought flow. During the early drought flow, the discharge decreases as the inverse square root of time ( Q ∝ 1/ √ t(Polubarinova-Kochina (1962)). Later, the discharge decreases as the inverse square of time (Q ∝ 1/t 2(Boussinesq, 1903)). A laboratory aquifer (homogeneous and bidimensional) submitted to artificial rainfall confirms the existence of these asymptotic regimes. This simplified experimental setup generates a realistic flood signal, in the absence of surface runoff. Field observation in the catchment of the Quiock Creek, Guadeloiipe reveals a similar behaviour. The water table and the river discharge evolve simultaneously during rainfall, and conform to theory. Like in our laboratory experiment, this aquifer reacts non-linearly to forcing by rainfall. The river discharge from three other catchments (Plynlimon, Wales and Laval, France) confirms this non-linear reaction : ˙Q ∝ R n , with n > 1. The exponent, however, is different from 3/2. A preliminary laboratory experiment suggests that this breakdown of the Dupuit-Boussinesq theory is due to vertical groundwater flow
Wronski, Maciej. „Couplage du contact et du frottement avec la mécanique non linéaire des solides en grandes déformations : application à l'étude des blocs de mousse en polyuréthane“. Compiègne, 1994. http://www.theses.fr/1994COMPD712.
Der volle Inhalt der QuelleHelal, Jean-Noël. „Discrimination de signaux électromyographiques non stationnaires : application à la contraction dynamique“. Compiègne, 1990. http://www.theses.fr/1990COMPD229.
Der volle Inhalt der QuelleKhabbazi, Abdelhamid. „Etude des écoulements le long d'une paroi verticale non isotherme, dans une cavité fermée à grand nombre de Rayleigh“. Toulouse 3, 1993. http://www.theses.fr/1993TOU30007.
Der volle Inhalt der QuelleBeydoun, Hussein. „Estimation de paramètres en milieux poreux non saturés en eau : Approche expérimentale et modélisation“. Université Louis Pasteur (Strasbourg) (1971-2008), 2005. http://www.theses.fr/2005STR13047.
Der volle Inhalt der QuelleUnsaturated water flow in porous media is classically modelled by Richards equation. Solving this equation requires the expression of the water content and of the hydraulic conductivity with respect to capillary pressure. These expression depend on the intrinsic hydraulic parameters of the porous medium. Some of these parameters are physically measurable whereas some others need indirect evaluation. The objective of this work is to identify all the hydraulic parameters (of a sand) using inverse modeling of a drainage experiment performed on a laboratory column. This identification is carried out for homogeneous and heterogeneous medium. To this end, experimental device and protocol are developed to depict the drainage system and to improve both the resolution of the hydrodynamic problem (Richards equation) and the inverse procedure (Marquardt algorithm). The aim is also to evaluate uncertainty on parameters and model sensitivity as regard measured observations
Koprnicky, Jan. „Modèles de conductivité électrique pour lampes à décharge“. Toulouse 3, 2008. http://thesesups.ups-tlse.fr/171/.
Der volle Inhalt der QuelleThis Ph. D. Thesis deals with light discharges modelling for description of electric circuits. It is not modelling of internal behaviour of a plasma, but its equivalent conductivity. The parameters of conductivity model are determined from measured voltage and current characteristics of discharge lamps. This model does not require any technological data from lamp producers. The Matlab/Matlab Simulink is used for data processing of u(t); i(t), application of identification algorithms and electric circuits simulation. The simulated results are compared with measurements. The model is tested in simulations of low and high pressure discharge lamps in circuits with magnetic ballasts
Okutmustur, Baver. „Méthodes de volumes finis pour les lois de conservation hyperboliques non-linéaires posées sur une variété“. Paris 6, 2010. http://www.theses.fr/2010PA066221.
Der volle Inhalt der QuelleHalab, Abdellatif. „Modélisation d'écoulements instationnaires en conduites élastiques non uniformes : application au réseau "aorto-tibial" en présence de sténoses et prothèses artérielles“. Toulouse 3, 1993. http://www.theses.fr/1993TOU30117.
Der volle Inhalt der QuelleChagneau, Pierrette. „Modélisation bayésienne hiérarchique pour la prédiction multivariée de processus spatiaux non gaussiens et processus ponctuels hétérogènes d'intensité liée à une variable prédite : application à la prédiction de la régénération en forêt tropicale humide“. Montpellier 2, 2009. http://www.theses.fr/2009MON20157.
Der volle Inhalt der QuelleOne of the weak points of forest dynamics models is the recruitment. Classically, ecologists make the assumption that recruitment mainly depends on both spatial pattern of mature trees and environment. A detailed inventory of the stand and the environmental conditions enabled them to show the effects of these two factors on the local density of seedlings. In practice, such information is not available: only a part of seedlings is sampled and the environment is partially observed. The aim of the paper is to propose an approach in order to predict the spatial distribution and the seedlings genotype on the basis of a reasonable sampling of seedling, mature trees and environmental conditions. The spatial pattern of the seedlings is assumed to be a realization of a marked point process. The intensity of the process is not only related to the seed and pollen dispersal but also to the sapling survival. The sapling survival depends on the environment; so the environment must be predicted on the whole study area. The environment is characterized through spatial variables of different nature and predictions are obtained using a spatial hierarchical model. Unlike the existing models which assume the environmental covariables as exactly known, the recruitment model we propose takes into account the error related to the prediction of the environment. The prediction of seedling recruitment in tropical rainforest in French Guiana illustrates our approach
Nsir, Khalifa. „Experimental and numerical study of the migration of dense non-aqueous phase liquid in saturated porous medium at Darcy scale“. Strasbourg, 2009. https://publication-theses.unistra.fr/public/theses_doctorat/2009/NSIR_Khalifa_2009.pdf.
Der volle Inhalt der QuelleThe immiscible displacement processes of a dense non-aqueous phase liquid (DNAPL) were studied in a sand-filled column. The considered pollutant is the Trichloroethylene, volatile and soluble chlorinated solvent, usually found in soils and ground water industrial pollution. Experiments were performed using two flow modes, namely vertical-upwards and vertical- downwards. A Fibre optic sensors were developed to measuring the arrival times of water/DNAPL at a control section of experiment device. The DNAPL pressure at the inlet and outlet section of the system was also monitored. The experiment program also allowed for measuring the local DNAPL saturations. Thereby, permitting to quantify evolving fingering patterns of non aqueuse phase liquid in the saturated porous medium. It has also been shown that the distribution of the non aqueuse phase liquid in the porous medium is heterogeneous. Furthermore, the obtained results underline that buoyancy forces (gravity) can have significant effects on the stability of the displacement process and on the oil recovery efficiency during injection of water. Numerically, a pore-scale network model based on spherical pore bodies and cylindrical pore throats was developed to simulate laboratory experiment. A computational approach based on the theory of packing spheres has also been developed to assess the geometric characteristics of the equivalent network of the used porous medium in the experiment. Good agreement between the numerical and experimental results was obtained. An important feature of the model is its capability to reproduce the observed pressure behaviour for stable and unstable displacement regimes
Corson, Nathalie. „Dynamique d'un modèle neuronal, synchronisation et complexité“. Phd thesis, Université du Havre, 2009. http://tel.archives-ouvertes.fr/tel-00453912.
Der volle Inhalt der QuelleEl, Alami Mustapha. „Contribution à l'étude thermique et dynamique des écoulements le long d'une paroi non uniformément chauffée dans une cavité à grand nombre de Rayleigh“. Toulouse, INSA, 1994. http://www.theses.fr/1994ISAT0009.
Der volle Inhalt der QuelleSolaque, Guzmán Leonardo Enrique. „Modelado, control y navegación para el vuelo autónomo de dirigibles“. Toulouse, INSA, 2007. http://www.theses.fr/2007ISAT0002.
Der volle Inhalt der QuelleThe aims of this thesis are the development of a dynamic model for the LAAS's Karma and los Andes University's UrAn airships, the elaboration of a set of base control laws of speed, altitude and heading in cruise flight, and optimal path planning and its pursuit. This work has been done within the framework of cooperation between the INSA of Toulouse and De los Andes University - Colombia. On the INSA side, this work has been made principally in the Robotic and Artificial Intelligent group of LAAS/CNRS, within the COMETS project. The LAAS robot was already equipped with sensors, an onboard CPU and radiofrequency links as FM and Ethernet whereas a radio-operated airship has been bought by De los Andes University to the Minizzep society. Then, instrumentation and on board CPU with Ethernet radio link have been installed. The first part of the document presents a mathematical model of the blimp dynamics. The analytic description of the model has been deduced from a dynamic and aerodynamic study. In a first time, the model parameters have been taken from precedent work based on wind tunnel experiments. Next to that, an identification of aerodynamic parameters of the grand model and also simplified models (called control model) were made with classical techniques and the Kalman filter as parametric estimator. A third part is devoted to the formulation of control strategies (PID, GPC and non-linear control by extended linearization principally), based on the decoupling of the velocity, the longitudinal and lateral dynamics. When this base controls are formulated, an approach to optimal planning based on the optimal control theory is presented. Two extensions to the initial model of path planning are proposed and their solutions are computed with numerical methods. A control for the following of the generated trajectory has been developed and is presented in the fourth chapter. These different control strategies have been validated by numerous simulation tests with and without wind. The speed and altitude controllers have been tested in the real airship structure (UrAn)
Xie, Ni. „Modélisation couplée du comportement hydromécanique des roches poreuses quasi-fragiles“. Thesis, Lille 1, 2011. http://www.theses.fr/2011LIL10035.
Der volle Inhalt der QuelleThis study concerns a micromechanics-based modeling of poromechanical behaviors of quasi-brittle porous rocks. The general framework adopted is that of up-scaling technique combined with irreversible thermodynamics. We first determine the effective property of quasi brittle rocks weakened by microcracks via the rigorous Eshelby-based homogenization method. The frictional sliding along surfaces of closed microcracks is interpreted as an irreversible dissipation process and responsible for the induced damage. An elastoplastic damage model is formulated with the inelastic strain inherently coupled with damage evolution. A Coulomb-type friction criterion serving as plastic yielding function and a strain energy release rate based damage criterion are proposed. The second part aims at extending the micromechanical modeling to poromechanical behavior of saturated porous rocks. The influence of fluid pressure is taken into account in the friction criterion through the concept of local effective stress. It is also manifested that the frictional sliding between crack surfaces generates volumetric dilatancy and causes reduction in fluid pressure. Applications of the proposed model to typical brittle rocks are presented and compared with experimental data in both drained and undrained triaxial tests. The last part of this dissertation deals with the hydromechanical modeling of single fracture subject to normal stress. Both experimental studies and theoretical modeling are carried out. The generalized Biot coefficient, in the form of a function of the fracture displacement, is introduced to describe the coupled behavior between fracture deformation and pore fluid pressure
Taing, Cécile. „Dynamique de concentration dans des équations aux dérivées partielles non locales issues de la biologie“. Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS077.
Der volle Inhalt der QuelleThis thesis focuses on the dynamics of Dirac mass concentrations in non-local partial differential and integro-differential equations motivated by evolutionary biology. We consider population models structured in phenotypical traits and, taking into account adaptation and mutation phenomena, we aim to describe the selection of the fittest traits in a given environment. The mathematical modeling of these biological problems leads to nonlinear and nonlocal equations, with a small parameter that induces two time-scales. The asymptotic solutions to these equations are population distributions on the traits space and concentrate in Dirac masses located on the dominant traits. In the first part, we study the Dirac mass dynamics in a chemostat model, using a Hamilton-Jacobi formulation. The chemostat model is a system of equations describing the dynamics of consumers and nutrients in a bioreactor. In a second part, we investigate a competition model structured in age and phenotypical traits. By means of an appropriate factorization, we obtain the asymptotic limit of the solution as a decomposition into two profiles, one in age, the other in traits. When mutations are introduced, a Hamilton-Jacobi equation arises and we prove a uniqueness result of the solution to this equation in the framework of viscosity solutions. The last part is devoted to sexual population models. These models under investigation include asymmetric trait heredity or asymmetric trait-dependent fecundity between the parents: each individual inherits mostly its traits from the female
Jules, Valentin. „Écoulement dans un aquifère non confiné profond alimenté par la pluie“. Thesis, Université de Paris (2019-....), 2020. http://www.theses.fr/2020UNIP7074.
Der volle Inhalt der QuelleDuring a rain event, water infiltrates into the ground where it flows slowly towards a river. The time scale and the geometry of this flow control the chemical composition and the discharge of the river. We use a tank filled with glass beads to simulate this process in a simplified laboratory experiment. A sprinkler pipe generates rain, which infiltrates into the porous material. Groundwater exits this laboratory aquifer througha side of the tank. Guérin et al. (2014) investigated the case of a quasi-horizontal flow. In nature, however, groundwater often follows non-horizontal flowlines. To create a vertical flow, we place the outlet of our experiment high above its bottom. Long after the rain started, in steady state, we can describe the flow in our aquifer with a combination of complex analysis and numerical methods. The distribution of travel times can thus gives informations about the aquifer geometry. More over, we find that, during rainfall, the discharge Q increases as the rainfall rate R times the time t (Q ∝ Rt). This laboratory aquifer thus responds linearly to the forcing. This response give informations about hydrological properties of the aquifer
Andrade, João Rodrigo. „Spectral analysis of the turbulent energy cascade and the development of a novel nonlinear subgrid-scale model for large eddy simulation“. Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1I006/document.
Der volle Inhalt der QuelleThe purpose of the present work is to analyze and to provide an enhancement of the knowledge about the subgrid-scale behavior and to propose novel nonlinear subgrid-scale models for large eddy simulations of turbulent fluid flows. In this way, the present thesis is subdivided into three main parts. The first topic is an analysis of the statistical uncertainties associated with direct numerical simulation data for turbulent channel flow, showing a novel physicallybased quantification of these errors. In this analysis, the mean velocity error is estimated by considering the Reynolds stress tensor, and using the balance of mean force equation. This analysis is performed in order to verify the quality of the statistical data coming from the direct numerical simulation applied in the present work. Secondly, seeking to understand the contained physics in the whole wavenumber spectrum of turbulent flows, an analysis of the spectral turbulent kinetic energy budget in fully developed turbulent plane channel flow is performed. The analysis is focused on the influence of the Reynolds number on the spectral cascade of energy and the corresponding energy cascade in physical space in the presence of inhomogeneity and anisotropy. Finally, a novel nonlinear subgrid-scale model for large eddy simulation based on a set of objective tensors is presented. In the proposed closure model, the modeled subgrid-scale stress tensor is a function of the resolved rate-of-strain tensor and the resolved non-persistence-of-straining tensor, where both are local and objective kinematic entities. The non-persistence-of-straining tensor represents the local ability of the fluid to avoid being persistently stretched. To check the consistency of the proposed model, a priori and a posteriori tests are performed by simulating different wall-bounded turbulent flows. Comparisons with the exact subgrid-scale stress tensor and experimental data revealed that the inclusion of nonlinear terms on the subgrid-scale model can significantly increase the accuracy of the results, showing the great potential of the proposed tensorial base
Belfort, Benjamin. „Modélisation des écoulements en milieux poreux non saturés par la méthode des éléments finis mixtes hybrides“. Université Louis Pasteur (Strasbourg) (1971-2008), 2006. https://publication-theses.unistra.fr/public/theses_doctorat/2006/BELFORT_Benjamin_2006.pdf.
Der volle Inhalt der QuelleThis study deals with unsaturated water flow modeling. After characterizing the considered porous media, the deterministic model based on Richards’ equation is described. Its limits and alternative approaches are mentioned. The mixed hybrid finite element method is presented and an original mass lumping technique is proposed to avoid unphysical oscillations, that could appear when sharp infiltration fronts are simulated. Estimation of relative conductivity on each cell of the discretized domain is an essential aspect to improve the results’ accuracy. Various formulations are depicted. Comparisons performed on several test cases show that the weighted formulation should be preferred. Another part is also devoted to non linearities management. The mixed form of Richards’ equation is kept. According to our investigations, the variable switching algorithm is the most efficient technique. Concerning the time step control, heuristic techniques could valuably be replaced by a priori methods, which establish a link between the temporal error and the time step size. Order extrapolation method can be efficiently combined with an integral controller. In the last part of this manuscript, all 1D optimisations are generalized in a 2D algorithm. Test cases are proposed to estimate its efficiency compared to classical methods
Castillo, Zamora José de Jesús. „Conception, Modélisation et Contrôle d'un Système Multi-Drones pour la Manipulation Aérienne“. Electronic Thesis or Diss., université Paris-Saclay, 2021. http://www.theses.fr/2021UPASG051.
Der volle Inhalt der QuelleA recent and exciting topic within the field of autonomous aerial vehicles is the interaction with the surrounding environment via in-flight manipulation, including retrieving, transport and deployment, which unveils an enormous potential vis-a-vis industrial and service applications. In this regard, the actual thesis focuses on the conception and energy-based dynamical study of a multi-link unmanned aerial system able to perform manipulation tasks. The study of the aforementioned robotic aerial system includes the control of the flying multi-link vehicle by the sliding mode control theory and the conception of Lyapunov-based controllers alongside the application of Kalman Filters for state and disturbances estimation. The last part of the thesis is devoted to the examination of time-delays effects on unmanned aerial systems. Detailed simulation results are provided to prove the effectiveness of the overall thesis proposal
Lecuyer-Le, Bris Romain. „Modélisation numérique et expérimentale de la captation d'énergie houlomotrice : application aux essais à échelle réduite en bassin“. Thesis, Brest, 2022. http://theses-scd.univ-brest.fr/2022/These-2022-SML-Mecanique_genie_mecanique_mecanique_des_fluides_et_energetique-LECUYER_LE_BRIS_Romain.pdf.
Der volle Inhalt der QuelleThe behaviour of wave energy converters (WEC) is non-linear and complex to model accurately, especially due to the fluid–structure interaction and the randomness of the wave. The ability of a WEC to recover some of the wave energy depends on the control strategy used and the reliability of the behaviour model. Numerical computation time must remain reasonable in order to allow real–time control. In this context, perfect fluid calculations are used to model the fluid-structure interaction at first order. This diffraction–radiation approach highlights the delay functions of the system, a detailed analysis of which has been carried out in this work and illustrated on a reference case. This thesis proposes to establish a method applicable to the modelling of any type of multi-body WEC. The formulation of the hydrodynamic forces resulting from the assumptions of perfect fluid is then supplemented with semi–empirical terms in order to take into account non–linear effects. The viscous forces represented are particularly influential in the vicinity of the motion resonances. This method also allows the integration of experimental data into the numerical model. Experimental work was therefore carried out in order to understand, quantify and integrate the effects observed experimentally for an anchored body into the numerical model. Finally, elements in favor of an experimental campaign for a two-body system are presented
Lemacha, Hassan. „Etude expérimentale et numérique des transferts hydriques et de soluté dans un milieu poreux non saturé-saturé“. Poitiers, 2006. http://www.theses.fr/2006POIT2349.
Der volle Inhalt der QuelleKo, Gaelle Kafira. „Etude et modélisation dynamique d'un concentrateur à miroir linéaire de Fresnel“. Thesis, Perpignan, 2019. http://www.theses.fr/2019PERP0018/document.
Der volle Inhalt der QuelleAmong the different technologies of concentrated solar power plant, the linear Fresnel, thanks to its simplicity, appears the most adapted to rural area of Sub Sahara region. A linear Fresnel collector of 7.5 m² has been built in “laboratoire énergies renouvelables et efficacité énergétique (LabEREE)”. The collector have been designed using material available locally by local man power. This reduces the total cost of the technology and makes it affordable for local population. The collector has been characterized in order to find optical, thermal and global efficiencies. In first time, a review on different linear Fresnel collector allows finding the technology that is most adapted to the Sub-Saharan region. An optical and thermal model of the collector has been done as a tool for designing and optimisation. The experimental results enable to validate the different models done. The collector has an effective concentration factor of 6 and a global efficiency of 21%
Reveillon, Julien. „Simulation dynamique des grandes structures appliquée aux flammes turbulentes non-prémélangées“. Rouen, 1996. http://www.theses.fr/1996ROUES071.
Der volle Inhalt der QuelleNiesner, Christophe. „Sensibilité et robustesse à l'incertitude paramétrique : une approche Bond Graph“. Ecole Centrale de Lille, 2005. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/2005/50376-2005-Niesner.pdf.
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