A preocupação com o impacto ambiental decorrente da implantação e operação de novas linhas metroferroviárias faz com que na elaboração dos projetos de via permanente sejam frequentemente adotados sistemas amortecedores de vibrações e ruídos secundários. As vibrações em vias de metrô são causadas principalmente pelo contato roda-trilho e são propagadas pela estrutura do túnel e pelas distintas camadas de solo podendo chegar às edificações lindeiras, onde, dependendo da intensidade, provocam desconforto aos usuários da edificação e mau funcionamento de equipamentos. Uma solução de atenuação largamente empregada atualmente em locais críticos é o \"sistema massa mola\". O sistema \"massa mola\" é composto por lajes de concreto armado, denominadas lajes flutuantes, apoiadas sobre materiais resilientes. De forma geral, quanto menor a frequência natural deste sistema, maior a atenuação das vibrações. No entanto, a utilização de apoios excessivamente flexíveis para obtenção de baixas frequências pode acarretar problemas operacionais em função de deslocamentos e acelerações excessivos das lajes flutuantes. Este projeto tem como objetivo o estudo do comportamento dinâmico das lajes flutuantes de concreto armado utilizadas em sistemas \"massa mola\" principalmente com relação à atenuação de vibrações e nível de vibrações na via permanente durante a passagem dos trens metropolitanos. A avaliação foi realizada utilizando modelos numéricos calibrados com dados experimentais obtidos nas linhas do Metrô de São Paulo. / Deploying and operating subway lines cause growing concern about environmental impact, making necessary in new lines projects the adoption of damping systems for no propagation of noise and vibration arising from traffic from trains. The vibrations in a subway track are mainly caused by wheel-rail contact and are propagated by tunnel structure and soil layers, reaching the neighboring buildings and causing annoyance residents in building. Equipment failures represent a consequence as well. A mitigation solution widely employed in critical locations is the known \"mass spring system\". The \"mass spring system\" system is composed of reinforced concrete slabs, so called floating slabs, resting on resilient materials. In general, greater attenuation of vibrations can be attained with lower natural frequency of system. However, the use of flexible supports for obtaining excessively low frequencies can cause operational problems due to excessive accelerations and displacements of the floating slab. This project aims to study the dynamic behavior of reinforced concrete floating slabs used in systems\' mass spring particularly with respect to mitigating vibrations and level of vibrations during the passage of the commuter trains. The evaluation was performed using numerical models calibrated with experimental data obtained in the lines of the São Paulo Metro.

A preocupação com o impacto ambiental decorrente da implantação e operação de novas linhas metroferroviárias faz com que na elaboração dos projetos de via permanente sejam frequentemente adotados sistemas amortecedores de vibrações e ruídos secundários. As vibrações em vias de metrô são causadas principalmente pelo contato roda-trilho e são propagadas pela estrutura do túnel e pelas distintas camadas de solo podendo chegar às edificações lindeiras, onde, dependendo da intensidade, provocam desconforto aos usuários da edificação e mau funcionamento de equipamentos. Uma solução de atenuação largamente empregada atualmente em locais críticos é o \"sistema massa mola\". O sistema \"massa mola\" é composto por lajes de concreto armado, denominadas lajes flutuantes, apoiadas sobre materiais resilientes. De forma geral, quanto menor a frequência natural deste sistema, maior a atenuação das vibrações. No entanto, a utilização de apoios excessivamente flexíveis para obtenção de baixas frequências pode acarretar problemas operacionais em função de deslocamentos e acelerações excessivos das lajes flutuantes. Este projeto tem como objetivo o estudo do comportamento dinâmico das lajes flutuantes de concreto armado utilizadas em sistemas \"massa mola\" principalmente com relação à atenuação de vibrações e nível de vibrações na via permanente durante a passagem dos trens metropolitanos. A avaliação foi realizada utilizando modelos numéricos calibrados com dados experimentais obtidos nas linhas do Metrô de São Paulo. / Deploying and operating subway lines cause growing concern about environmental impact, making necessary in new lines projects the adoption of damping systems for no propagation of noise and vibration arising from traffic from trains. The vibrations in a subway track are mainly caused by wheel-rail contact and are propagated by tunnel structure and soil layers, reaching the neighboring buildings and causing annoyance residents in building. Equipment failures represent a consequence as well. A mitigation solution widely employed in critical locations is the known \"mass spring system\". The \"mass spring system\" system is composed of reinforced concrete slabs, so called floating slabs, resting on resilient materials. In general, greater attenuation of vibrations can be attained with lower natural frequency of system. However, the use of flexible supports for obtaining excessively low frequencies can cause operational problems due to excessive accelerations and displacements of the floating slab. This project aims to study the dynamic behavior of reinforced concrete floating slabs used in systems\' mass spring particularly with respect to mitigating vibrations and level of vibrations during the passage of the commuter trains. The evaluation was performed using numerical models calibrated with experimental data obtained in the lines of the São Paulo Metro.

La nécessité de simulations de tissus mous, tels que les organes internes, se pose avec le progrès des domaines scientifiques et médicaux. Le but de ma thèse est de développer un nouveau modèle générique, topologique et physique, pour simuler les organes humains. Un tel modèle doit être facile à utiliser, doit pouvoir effectuer des simulations en temps réel avec un niveau de précision permettant l'utilisation à des fins médicales. Cette thèse explore de nouvelles méthodes de simulation et propose des améliorations pour la modélisation de corps déformables. Les méthodes proposées visent à pouvoir effectuer des simulations rapides, robustes et fournissant des résultats physiquement précis. L'intérêt principal de nos solutions réside dans la simulation de tissus mous élastiques a petites et grandes déformations à des fins médicales. Nous montrons que pour les méthodes existantes, la précision pour simuler librement des corps déformables ne va pas de pair avec la performance en temps de calcul. De plus, pour atteindre l'objectif de simulation rapide, de nombreuses approches déplacent certains calculs dans une étape de pré-traitement, ce qui entraîne l'impossibilité d'effectuer des opérations de modification topologiques au cours de la simulation comme la découpe ou le raffinement. Dans cette thèse, le cadre utilisé pour les simulations s'appelle TopoSim. Il est conçu pour simuler des matériaux à l'aide de systèmes masses-ressorts (MSS) avec des paramètres d'entrée spécifiques. En utilisant un MSS, qui est connu pour sa simplicité et sa capacité à effectuer des simulations temps réel, nous présentons plusieurs améliorations basé physiques pour contrôler les fonctionnalités globales du MSS qui jouent un rôle clé dans la simulation de tissus réels. La première partie de ce travail de thèse vise à reproduire une expérience réelle de simulation physique qui a étudié le comportement du tissu porcin à l'aide d'un rhéomètre rotatif. Son objectif était de modéliser un corps viscoélastique non linéaire. A partir de l'ensemble des données acquises, les auteurs de l'expérience ont dérivé une loi de comportement visco-élastique qui a ensuite été utilisée afin de la comparer avec nos résultats de simulation. Nous définissons une formulation des forces viscoélastiques non linéaires inspirée de la loi de comportement physique. La force elle-même introduit une non linéarité dans le système car elle dépend fortement de l'amplitude de l'allongement du ressort et de trois paramètres spécifiques à chaque type de tissu. La seconde partie de la thèse présente notre travail sur les forces de correction de volume permettant de modéliser correctement les changements volumétriques dans un MSS. Ces forces assurent un comportement isotrope des solides élastiques et un comportement correct du volume quel que soit la valeur du coefficient de Poisson utilisé. La méthode nécessite de résoudre deux problèmes: l'instabilité provoquant des plis et les contraintes de Cauchy. Nos solutions à ces limitations impliquent deux étapes. La première consiste à utiliser trois types de ressorts dans un maillage entièrement hexaédrique: les arêtes, les faces diagonales et les diagonales internes. Les raideurs des ressorts dans le système ont été formulées pour obéir aux lois mécaniques de base. La deuxième étape consiste à ajouter des forces de correction linéaires calculées en fonction du changement de volume et des paramètres mécaniques du tissu simulé, à savoir le coefficient de Poisson et le module de Young [etc…] / The need for simulations of soft tissues, like internal organs, arises with the progress of the scientific and medical environments. The goal of my PhD is to develop a novel generic topological and physical model to simulate human organs. Such a model shall be easy to use, perform the simulations in the real time and which accuracy will allow usage for the medical purposes.This thesis explores novel simulation methods and improvement approaches for modeling deformable bodies. The methods aim at fast and robust simulations with physically accurate results. The main interest lies in simulating elastic soft tissues at small and large strains for medical purposes. We show however, that in the existing methods the accuracyto freely simulate deformable bodies and the real-time performance do not go hand in hand. Additionally, to reach the goal of simulating fast, many of the approaches move the necessary calculations to pre-computational part of the simulation, which results in inability to perform topological operations like cutting or refining.The framework used for simulations in this thesis is designed to simulate materials using Mass Spring Systems (MSS) with particular input parameters. Using Mass-Spring System, which is known for its simplicity and ability to perform fast simulations, we present several physically-based improvements to control global features of MSS which play the key role in simulation of real bodies

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-06-08T11:17:37Z No. of bitstreams: 1 ricardosilvacampos.pdf: 8528381 bytes, checksum: 29e3f07b2a4b4215d4e42d012e0f5df3 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T13:24:53Z (GMT) No. of bitstreams: 1 ricardosilvacampos.pdf: 8528381 bytes, checksum: 29e3f07b2a4b4215d4e42d012e0f5df3 (MD5) / Made available in DSpace on 2016-07-13T13:24:53Z (GMT). No. of bitstreams: 1 ricardosilvacampos.pdf: 8528381 bytes, checksum: 29e3f07b2a4b4215d4e42d012e0f5df3 (MD5) Previous issue date: 2016-02-15 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico / Este trabalho apresenta o simulador FisioPacer, que é um simulador que reproduz a propagação do pulso elétrico pelo tecido cardíaco e a sua deformação mecânica. Foi utilizado um autômato celular acoplado a um sistema massa-mola para que as simulações sejam realizadas rapidamente. Foi também utilizado um algoritmo genético para automaticamente determinar parâmetros do modelo de forma a reproduzir outros experimentos in silico e o comportamento de um ventrículo real. Com intuito de validar o modelo foram feitos setenta e dois experimentos e os resultados foram comparados com outro simulador robusto, baseado em equações diferenciais. As comparações mostraram que o FisioPacer reproduziu satisfatoriamente o comportamento do tecido, sendo até quinze mil vezes mais rápido. Além disto, foram simuladas as funcionalidades eletromecânicas de um ventrículo esquerdo a partir de dados de um paciente, obtidos via ressonância magnética. / This work proposes a computational heart model named FisioPacer, which aims to reproduce the electrical pulse propagation over the cardiac tissue and its mechanical deformation. In order to perform fast simulations, it was used a cellular automaton coupled with a mass-spring system. A genetic algorithm was also used to automatically adjust model parameters, in order to reproduce in silico experiments and a real left ventricle behavior. For the model validation, seventy two experiments were performed and the results were compared to another robust simulator, based on partial differential equations. The comparisons showed that the FisioPacer simulator could reproduce cardiac tissue electromechanics, with up to 15000-fold improvement in computational time. Furthermore, a real patient left ventricle was simulated, with data obtained via MRI.

Les travaux réalisés pendant mon doctorat répondent à la problématique de la simulation physique, en temps interactif, du comportement d'objets déformables soumis à des changements topologiques. Mes travaux ont abouti à la définition d'un nouveau modèle unifié couplant un modèle topologique complet et un modèle physique, pour la simulation physique d'objets déformables décomposés en éléments surfaciques comme volumiques, tout en réalisant pendant cette simulation des changements topologiques comme la découpe ou la subdivision locale d'un élément du maillage. Cette dernière opération a permis de proposer une méthode adaptative où les éléments du maillage sont raffinés selon un critère géométrique au cours de la simulation. Nous avons fait le choix des cartes combinatoires et plus particulièrement celui des complexes cellulaires linéaires, comme modèle topologique de notre modèle unifié. Ils ont l'avantage d'être génériques par rapport à la dimension de l'objet représenté mais également par rapport à la topologie des cellules en lesquelles l'objet est décomposé. Le système masses-ressort a, quant à lui, été choisi comme modèle physique de notre modèle unifié. L'avantage de ce dernier réside dans la simplicité de ses équations, son implémentation intuitive, son interactivité et sa facilité à gérer les changements topologiques. Enfin, la définition d'un modèle unifié nous a permis de proposer un modèle évitant la redondance d'informations et facilitant la mise à jour de ces dernières suite à des changements topologiques / The work made during my PhD, respond to the problematic of physical simulation of the behavior of deformable objects subject to topological changes in interactive time. My work resulted in the definition of a new unified model coupling a complete topological model and a physical model for physical simulation of deformable objects decomposed in surface as volume elements, while performing during this simulation topological changes such as cutting or subdivision local of a mesh element. This operation allowed us to propose an adaptive method where mesh elements are refined during the simulation according to a geometric criterion. For the topological model of our unified model, we made the choice of combinatorial maps and more particularly linear cellular complexes. Their main advantage of the latter is the simplicity of its equations, its intuitive implementation, its interactivity and its ease to handle topological changes. Finally, the definition of a unified model allowed us to propose a model avoiding duplication of information and facilitate the update after topological changes