La tendance actuelle dans le domaine du transport ferroviaire est d'intégrer des modules de puissance de plus en plus puissants dans des volumes de plus en plus réduits. Cela pose des problèmes, notamment en termes de fiabilité, car lors de leurs cycles de fonctionnement, les interrupteurs à semi-conducteurs et leur environnement immédiat sont soumis à des contraintes électro-thermo-mécaniques plus sévères. Cela peut entraine leur destruction et donc la défaillance de la fonction de conversion d'énergie. L'objectif principal de cette thèse est de décrire des modèles et des outils de simulation multi-physiques afin de caractériser ces contraintes. Nous avons choisi comme cas d'étude les fils de connexion dits «wire bonding». Ces fils sont, en effet, considérés comme l'un des points faibles en ce qui concerne la durée de vie des modules de puissance, utilisés dans les systèmes embarqués notamment dans le ferroviaire. Dans ce contexte multi-physique, nous avons développé des modèles, numériques, éléments finis, analytiques, 3D ou 1D, afin de déterminer les contraintes thermomécaniques lors du passage du courant dans ces fils. A travers les modèles décrits et les résultats de simulation présentés, nous caractérisons le comportement des fils d'un point de vue électrique, thermique, magnétique ou mécanique. Plus précisément les interactions électromagnétiques, électrothermiques, électromécaniques ou thermomécaniques entre modèles et entre outils de simulation sont discutées. Les résultats sont confrontés aux mesures thermiques et de déplacement. Ces dernières sont réalisées par le biais de prototypes expérimentaux. Le mode de sollicitation utilisé est dit actif. Un régime de courant, continu ou alternatif, est appliqué au système. La réponse thermique et mécanique du système est alors obtenue. Les conclusions de cette étude permettent d'une part de mieux caractériser le comportement électro thermomécanique des fils de bonding et de mieux comprendre l'origine des modes de défaillance de cette technologie d'interconnexion. D'autre part, une démarche d'utilisation des modèles et outils logiciels multi physiques pour une simulation électro thermomécanique est présentée / The trend in the field of railway transport is to integrate increasingly powerful power modules in smaller volumes. This is problematic, especially in terms of reliability: during their cycles of operation, the semiconductor switches and their immediate environment are subject to tougher electro-thermo-mechanical stresses. This can lead to their destruction and then, to the failure of the energy conversion function. The main goal of this work is to describe the models and multi-physics simulation tools to characterize these stresses. We chose as a case study the connection wire called “wire bonding”. These wires are, indeed, considered one of the weaknesses of the life time of the power module used in embedded systems, particularly in railway applications. In this multi-physics context, we have developed numerical, finite elements, analytical, 3D or 1D models to determine the thermo-mechanical stresses during the current flow through the wires. Thanks to the models described and the simulation results presented, we characterize the behavior of the wire for an electrical, thermal, magnetic or mechanical point of view. More precisely, the electro-magnetic, electro-thermal, electro-mechanical or thermo-mechanical interactions between models and between simulation tools are discussed. The results are compared to thermal and displacement measurements. They are realized thanks to experimental prototypes. The type of solicitation is called active. A system of direct or alternating current is applied to the system. The thermal and mechanical response of the system is obtained. The conclusions of this study allow, on the one hand, characterizing the electro thermo-mechanical behavior of wires bonding and understanding the origin of the failure modes of this technology. On the other hand, a way of using models and multi-physics software tools for an electro thermo-mechanical simulation is presented

Submitted by Verena Pereira (verenagoncalves@uefs.br) on 2018-07-11T22:28:24Z No. of bitstreams: 1 TFC - MARCELO LAGO ARA?JO.pdf: 15427093 bytes, checksum: 0f71c2c794a5b17a6bd6de1c0dedb9df (MD5) / Made available in DSpace on 2018-07-11T22:28:24Z (GMT). No. of bitstreams: 1 TFC - MARCELO LAGO ARA?JO.pdf: 15427093 bytes, checksum: 0f71c2c794a5b17a6bd6de1c0dedb9df (MD5) Previous issue date: 2017-12-21 / With Radio Astronomy we can study the Universe through the radio waves that reach us, taking advantage of the windows of atmospheric observation. It is an Astronomy branch that covers the development of new technologies for the capture, detection, storage and analysis of immense amounts of data. In a scenario of several technological innovations, the scientific developments from Radio Astronomy have an impact on other fields of knowledge. The study of this Science is a pertinent resource for the teaching of components of Physics, in an interdisciplinary way. Before proposing the Educational Products, with Radio Astronomy as its theme, it was necessary to experience its practical aspects, from the construction of prototypes to radioastronomical observations with experimental radio telescopes, such as Radio Jove. Field experiences have become a practice that can be adopted by other teachers. They provided knowledge for the development of the proposed Educational Products: Hertz Experiment, Adapted Galena Radio, Io-Jupiter Simulator, Pulsar Simulator, Ku Band Radio Telescope, RCFM Simulator, Teacher Workshop and Website, repository of Educational Product guides. They also collaborated on the developed methodology that includes the proposal of classroom application with the use of Conceptual Maps and V Diagrams, for diagnosis, evaluation and conduction of the experiments. The products were tested and evaluated qualitatively, from their application in events of scientific dissemination in formal and non-formal teaching environments. In these evaluations, they obtained a positive qualification that indicates their relevance to the promotion of meaningful learning, based on the items analyzed / Com a Radioastronomia podemos estudar o Universo por meio das ondas de r?dio que chegam at? n?s, aproveitando as janelas de observa??o atmosf?rica. ? um ramo da Astronomia que abrange o desenvolvimento de novas tecnologias para a capta??o, detec??o, armazenamento e an?lise de imensas quantidades de dados. Num cen?rio de diversas inova??es tecnol?gicas, os desenvolvimentos cient?ficos oriundos da Radioastronomia t?m impacto em outros campos do saber e o estudo desta Ci?ncia ? um recurso pertinente para o Ensino de componentes da F?sica, em car?ter interdisciplinar. Antes de propor os Produtos Educacionais, tendo a Radioastronomia como tema, foi necess?rio vivenciar seus aspectos pr?ticos, desde a constru??o de prot?tipos ?s observa??es radioastron?micas com radiotelesc?pios experimentais, como o Radio Jove. As viv?ncias em campo se constitu?ram numa pr?tica que pode ser adotada por outros professores. Forneceram conhecimentos para o desenvolvimento dos Produtos Educacionais propostos: Experimento de Hertz, R?dio de Galena Adaptado, Simulador de Io-J?piter, Simulador de Pulsar, Radiotelesc?pio Banda Ku, Simulador RCFM, Oficina para Professores e o s?tio na Internet, reposit?rio dos roteiros dos Produtos Educacionais. Tamb?m colaboraram para a metodologia desenvolvida que inclui a proposta de aplica??o em sala de aula com a utiliza??o de Mapas Conceituais e Diagramas em V?, para diagn?stico, avalia??o e condu??o dos experimentos. Os produtos foram testados e avaliados qualitativamente, a partir de sua aplica??o em eventos de divulga??o cient?fica em ambientes formais e n?o formais de ensino. Nestas avalia??es, obtiveram qualifica??o positiva que indica a sua relev?ncia para a promo??o da aprendizagem significativa, a partir dos itens analisados