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La dynamique des structures assemblées est un sujet de recherche actuel. En particulier, une prédiction correcte de l'amortissement apporté par les liaisons vissés est devenu une condition essentiel pour un certain nombre d'applications, comme par exemple les avions et les véhicules spatiaux. En effet, pour ces applications, l’utilisation de matériaux avec un coefficient d'amortissement plus élevée, comme des matériaux visco-élastiques, est limité par les conditions de fonctionnement.Ces travaux apportent deux contributions principales. La première porte sur la phase de conception et modélisation, avec la création d'un système de connecteurs pour la reproduction des comportements normal et tangentiel d'une liaisons vissée. Cela est accomplie en considérant seulement les données physiques de la liaison et des surfaces en contact.La deuxième contribution concerne l’évaluation des propriétés dynamiques non-linéaires des assemblages. Un set d'outils de post-traitement utilisant le filtre de Kalman est développé pour réaliser une analyse modale non-linéaire pour les types d'essais les plus communs: les essais aux chocs, les essais en balayage sinus, et les essais en sinus aléatoire.Les méthodes développées ont été appliqués et évaluées sur une structure boulonnée réel, en soulignant les avantages et les inconvénients. Notamment, le filtre de Kalman permet une meilleure précision sur les paramétrés identifiés, mais le procédé d’initialisation du filtre est le problème principal. Une automatisation partiel de l’initialisation est prévu, ainsi que des conseils pratiques grâce à l’expérience acquise sur le sujet. / Bolted structures dynamics is an ongoing research topic. In particular, a correct prediction of the damping provided by bolted joints has became an essential requirement for a certain number of applications, such as aircrafts and space vehicles. In fact, for these applications, the use of materials with higher damping coefficients is limited by environmental conditions.This work provides two main contributions. The first one concerns the design and modeling phase, with the creation of a finite element connectors' system, that reproduces the bolted joint normal and tangential behaviors. The latter is accomplished only by taking into account readily available physical data, such as the bolted joint dimensions and the properties of the surfaces in contact. The second contribution regards the evaluation of assembled structures' nonlinear dynamic properties. A set of post-processing tools making use of the Kalman filter is developed to perform a nonlinear modal analysis for the most common types of experimental tests: impact hammer tests, sweep sine tests, and random vibration tests.The developed methods are then applied and evaluated on a real bolted structure, pointing out advantages and drawbacks. In particular, the Kalman filter allows for a higher accuracy in the determination of modal parameters, but the filter initialization is the main problem. A partial automation of the initialization task is provided, together with practical tips thanks to the experience gained on the subject.

本研究旨在針對電子連接器產業進行探索性研究，期能發現占據相當重要關鍵零組件地位的連接器，其產業態勢與競爭條件。本研究固然與傳統的研究方法相同，運用Aaker的策略分析架構進行探討，但亦頗多創新之處，譬如納進Porter的國家競爭力分析模型，討論產業與政府等因素間的相互依賴狀況，又納入司徒達賢的策略矩陣分析構面，討論個案公司與其他同業之間的競爭模型。本研究雖以個案公司為研究對象，但旁及其他競爭性公司共同討論，以了解個案公司的產業定位與遭遇的挑戰。 / This study is exploring the advantage of competition in Connector industry. It adopted Aaker’s model, which designed by strategic method to depict a SWOT to overall analysis of connector industry as well as Case Study Company. The main contribution is to offer a position within industry where has a vital network can help others to sustain the strong power. However, the environment is not as good as past, the trend will bring a move to mainland China, and the new competitors will appear, the Industry ought to encounter more challenge than have been met in Taiwan. This study has some characters involve in the National competitive model and the strategic matrix analysis method from Dr. Seeto. There are many persons were called on to the Case interview, However, only certain firms would be selected as delegation out of this industry.

Dans le contexte de la montée des préoccupations écologiques, le développement de véhicules de transports routiers s’oriente vers le développement de véhicules moins polluants à entraînement électrique comme les Véhicules Électriques Hybrides (VEHs) et les Véhicules tout Électriques (VEs). Avec l’augmentation des puissances requises et la réduction de l’espace disponible, la gestion thermique devient une préoccupation de plus en plus importante lors du développement des composants embarqués comme les moteurs/générateurs électriques, onduleurs, batteries et faisceaux électriques. Parmi eux, le faisceau électrique de puissance qui est typiquement composé de câbles électriques, de connecteurs et de boîtes de distribution de puissance ne peut être conçu de manière appropriée qu’à la suite d’une analyse thermique, électrique, chimique et mécanique approfondie.Cette thèse est écrite pour contribuer à l’optimisation de la conception électrothermique de faisceaux de câbles par des simulations afin de réduire la quantité de tests expérimentaux nécessaires pour leur développement. Des modèles théoriques pour la prédiction du comportement électrique et thermique de câbles électriques et des faisceaux de câbles sont passés en revue et adaptés aux exigences automobiles. La validation est accomplie en comparant les résultats de simulation avec ceux d’analyses élément finie (FEA) et de données de mesure. Une partie majeure de cette thèse aborde la simulation thermique de câbles électriques de longueur infinie suspendus dans l’air, prenant en compte les dépendances en température des résistances de conducteurs et la non-linéarité du coefficient de transfert thermique total à la surface du câble. L’influence des courants de blindage et de courants arbitraires dans les conducteurs sur la montée en température des câbles électriques est considérée dans des circuits thermiques équivalents et illustré par des exemples pratiques. / In the context of growing ecological concerns, the development of road transport vehicles moves itself toward the development of less polluting vehicles with electric drives such as Hybrid Electric Vehicles (HEVs) and full Electric Vehicles (EVs). With rising power requirements and reducing available space, thermal management is becoming an increasingly important concern during development of on-board vehicle components such as electric motor(s)/generator(s), power inverter(s), battery pack(s) and cable harnesses. Among them, the cable harness which is typically composed of electrical cables, connectors and power distribution boxes can only be designed properly after a detailed thermal, electrical, chemical and mechanical analysis.This thesis is written to contribute to the optimization of the electro-thermal design of cable harnesses through simulations and reduce the amount of experimental testing needed during their development. Theoretical models for the prediction of the electrical and thermal behavior of electric cables and cable harnesses are reviewed and adapted for automotive requirements. Validation is accomplished by comparing simulation results with Finite Element Analysis (FEA) and measurement data. A major part of this thesis addresses the thermal simulation of electrical cables of infinite length installed in air, taking into account the temperature dependencies of conductor resistances and non-linearity of the total heat transfer coefficient at the cable surface. The influence of shielding currents and arbitrary current loads in the conductors on the temperature rises within electric cables is also considered using thermal ladder networks and illustrated by practical examples. Because shielding currents in vehicles are not only caused by induced currents but also by functional electrical currents generated by low-voltage power sources, new theoretical studies and experimental observations for the estimation of these currents as a function of the vehicle electrical architecture and circuit characteristics are presented. A primary finding reveals that keeping the resistance of grounding connections low compared to that of the shielding connections is an appropriate but expensive means for limiting the transfer of functional currents in the shielding circuits. Finally, a complete and modular model for the prediction of transient temperatures along the length of cable harness sections is developed and validated based on the outcomes of all previous findings.

Pattern matching approaches in reverse engineering aim to incorporate domain knowledge and system documentation in the software architecture extraction process, hence provide a user/tool collaborative environment for architectural design recovery. This thesis presents a model and an environment for recovering the high level design of legacy software systems based on user defined architectural patterns and graph matching techniques. In the proposed model, a high-level view of a software system in terms of the system components and their interactions is represented as a query, using a description language. A query is mapped onto a pattern-graph, where a module and its interactions with other modules are represented as a group of graph-nodes and a group of graph-edges, respectively. Interaction constraints can be modeled by the description language as a part of the query. Such a pattern-graph is applied against an entity-relation graph that represents the information extracted from the source code of the software system. An approximate graph matching process performs a series of graph edit operations (i. e. , node/edge insertion/deletion) on the pattern-graph and uses a ranking mechanism based on data mining association to obtain a sub-optimal solution. The obtained solution corresponds to an extracted architecture that complies with the given query. An interactive prototype toolkit implemented as part of this thesis provides an environment for architecture recovery in two levels. First the system is decomposed into a number of subsystems of files. Second each subsystem can be decomposed into a number of modules of functions, datatypes, and variables.

Pattern matching approaches in reverse engineering aim to incorporate domain knowledge and system documentation in the software architecture extraction process, hence provide a user/tool collaborative environment for architectural design recovery. This thesis presents a model and an environment for recovering the high level design of legacy software systems based on user defined architectural patterns and graph matching techniques. In the proposed model, a high-level view of a software system in terms of the system components and their interactions is represented as a query, using a description language. A query is mapped onto a pattern-graph, where a module and its interactions with other modules are represented as a group of graph-nodes and a group of graph-edges, respectively. Interaction constraints can be modeled by the description language as a part of the query. Such a pattern-graph is applied against an entity-relation graph that represents the information extracted from the source code of the software system. An approximate graph matching process performs a series of graph edit operations (i. e. , node/edge insertion/deletion) on the pattern-graph and uses a ranking mechanism based on data mining association to obtain a sub-optimal solution. The obtained solution corresponds to an extracted architecture that complies with the given query. An interactive prototype toolkit implemented as part of this thesis provides an environment for architecture recovery in two levels. First the system is decomposed into a number of subsystems of files. Second each subsystem can be decomposed into a number of modules of functions, datatypes, and variables.

Freeways have had a strong influence not only on the urban transportation but also on downtown areas both physically and socially. Certainly, they have extended the commuting limits of the city and made lower land costs more accessible. However, many of the mid-century freeways, once championed by planners as tools for urban renewal, have created swaths of blight through city neighborhoods. Their negative impacts on the larger urban framework requires new ideas for healthier alternatives to aid in preserving and building sustainable cities. Removal of any downtown highway requires careful thought— even more consideration than when it was built. Quick solutions are what resulted in the problems that downtown highways of the Interstate-Era have today. If it is the simple interactions between people and place are that make up the positive aspects an urban environment, then what are the possibilities and strategies for removing urban highway, which are one of the primary impediments separating people in place in contemporary cities? This question is the focus of this thesis. At its core, the removal of freeways represents a trade-off between mobility objectives and economic development objectives. Evidence from other cities’ decisions to redesign or remove their downtown highways suggests multiple benefits. Making design changes, such as to replace a downtown highway with a well-designed surface boulevard, can stimulate economic activities without necessarily causing traffic chaos. Solutions come in different shapes and sizes. The selected case studies in this thesis reflect a diversity of approaches – suggesting no single strategy exists for addressing downtown highway issues. This reflects the fact that multiple alternatives must be considered in every situation because each approach varies in costs and opportunities. A typology of highway alternations derived from the case studies includes seven different techniques: burying, demolishing, taming, capping or bridging, elevating, retaining, and relocating. The final chapter applies the conclusions from the case studies to the Downtown Connector– Interstate 75/85– in Downtown Atlanta, Georgia. Urban design and transportation planning has an emerging new set of values. Transportation planning is seeking to promote alternate modes of transportation to the private vehicle, like transit, by foot, or by bicycle. We now understand that connectivity is not served only by highways but also by urban street networks that invite modes other than just automobiles. An important role for urban design will be to shape the way these interactions are made to benefit the citizens, its urban spaces, and the economy.

Made available in DSpace on 2015-03-26T13:28:35Z (GMT). No. of bitstreams: 1 texto completo.pdf: 3487297 bytes, checksum: 440345c34c1ab5834f45b26ae9b87375 (MD5) Previous issue date: 2014-09-12 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents the development of a parametric study on Crestbond shear connector through numerical modeling, evaluating its behavior with respect to strength and to the relative displacement between the concrete slab and the shear connector. The study covers the conception and improvement of numerical models for the parametric study, the development of an extensive research on the connector s parameters affecting its behavior, and an equation to predict the connector s ultimate strength, proposed at the end. The numerical models were created within the Finite Element software Abaqus, using nonlinear analysis and the concrete damaged plasticity model. The parametric study consisted on the analysis of 88 numerical simulations of push-out tests, as described on EN 1994-1-1:2004. The connection behavior was studied through these numerical tests. The obtained results allowed to define how each studied parameter influences the connector s behavior. It was also possible to define the desirable characteristics for the connector to be used in practice. In addition to these results, it was proposed a semi-empirical equation to evaluate the connector s ultimate strength which showed excellent correlation with most of the models, both experimental and numerical. / Este trabalho consiste no desenvolvimento de um estudo paramétrico do conector de cisalhamento tipo Crestbond por meio de modelagem numérica, avaliando o comportamento do conector quanto à capacidade resistente e ao deslizamento relativo entre conector e laje. O trabalho envolve o aperfeiçoamento e concepção de modelos numéricos para o estudo do conector, uma ampla investigação dos parâmetros que afetam o comportamento do conector, além da proposição de uma equação para a predição da sua capacidade resistente. Os modelos numéricos utilizados foram elaborados por meio do software de elementos finitos Abaqus, utilizando análise não-linear e o modelo de dano com plasticidade. O estudo paramétrico consistiu na análise de 88 simulações numéricas de ensaios tipo push-out, conforme a EN 1994-1-1:2004. Os resultados obtidos permitiram determinar como cada parâmetro estudado influencia o comportamento do conector e quais as características desejáveis para a aplicação do mesmo. Ao final do trabalho, propôs-se uma expressão semiempírica para a estimativa da carga máxima do conector que apresentou excelente correlação com grande parte dos modelos, tanto experimentais quanto numéricos.

Recentemente a utilização de estruturas mistas, aço concreto, vem ganhando espaço nas construções. Isso deve-se principalmente a economia de tempo em sua execução. Além disto, nesta solução a utilização do aço e do concreto otimiza as características estruturais de seus elementos: a resistência a tração do aço e a compressão do concreto. A transferência dos esforços entre os dois materiais possui grande influência no desempenho de uma estrutura mista, sendo comum a utilização de conectores de cisalhamento na região da interface entre estes dois materiais. O Eurocode 4 define um ensaio experimental denominado push-out de modo a determinar a resistência e ductilidade de conectores de cisalhamento. Seu desempenho é influenciado pelas resistências do concreto a compressão, as dimensões e taxa de armadura da laje de concreto, dimensões do perfil de aço, a disposição e a geometria dos conectores e pelas características dos aços utilizados no conector, no perfil e nas barras de reforço. Nota-se com isso uma grande quantidade de variáveis que influenciam o ensaio. Assim, o presente trabalho apresenta o desenvolvimento de um modelo em elementos finitos com base no programa ANSYS para simulação de ensaios push-out. Os resultados numéricos apresentados neste trabalho foram calibrados com resultados obtidos em ensaios experimentais existentes na literatura de ensaios push-out para conectores do tipo pino com cabeça (stud) e conectores tipo perfobond. Estes últimos apresentam elevada resistência sendo influenciados por inúmeros fatores como: número e diâmetro dos furos no conector e a inclusão ou não de barras de reforço extras nestes furos. / A continuous increase of the use of (steel & concrete) composite structures in constructions can be recently observed. This is mainly due to its faster execution time when compared to other construction alternatives. Additionally, these solutions optimize the structural characteristics of the involved materials: the steel tension capacity and the concrete compressive strength. The transfer of forces between these different materials greatly influences the composite structure performance, where typical solutions uses shear connectors at the concrete to steel interface. The Eurocode 4 defines an experimental test, denominated push-out, to determine the shear connectors strength and associated ductility capacity. Its performance is influenced by the concrete compressive strength, slab dimensions and adopted reinforcing bar area, steel profile dimensions, shear connectors geometry and disposition and by the mechanical characteristics of the connector, profile and reinforcing bars steels. All these aspects indicate that a great number of variables can influence the test. This study presents the development of a finite element model, based on the ANSYS program, to simulate push-out tests. The numerical results presented in this investigation were calibrated against experiments reported in the literature for stud and Perfobond shear connectors. The Perfobond connectors present a substantial shear capacity being influenced by several factors like: connectors hole number and diameter and by the adoption, or not, of extra reinforcing bars passing through the connector holes.

Recentemente a utilização de estruturas mistas, aço concreto, vem ganhando espaço nas construções. Isso deve-se principalmente a economia de tempo em sua execução. Além disto, nesta solução a utilização do aço e do concreto otimiza as características estruturais de seus elementos: a resistência a tração do aço e a compressão do concreto. A transferência dos esforços entre os dois materiais possui grande influência no desempenho de uma estrutura mista, sendo comum a utilização de conectores de cisalhamento na região da interface entre estes dois materiais. O Eurocode 4 define um ensaio experimental denominado push-out de modo a determinar a resistência e ductilidade de conectores de cisalhamento. Seu desempenho é influenciado pelas resistências do concreto a compressão, as dimensões e taxa de armadura da laje de concreto, dimensões do perfil de aço, a disposição e a geometria dos conectores e pelas características dos aços utilizados no conector, no perfil e nas barras de reforço. Nota-se com isso uma grande quantidade de variáveis que influenciam o ensaio. Assim, o presente trabalho apresenta o desenvolvimento de um modelo em elementos finitos com base no programa ANSYS para simulação de ensaios push-out. Os resultados numéricos apresentados neste trabalho foram calibrados com resultados obtidos em ensaios experimentais existentes na literatura de ensaios push-out para conectores do tipo pino com cabeça (stud) e conectores tipo perfobond. Estes últimos apresentam elevada resistência sendo influenciados por inúmeros fatores como: número e diâmetro dos furos no conector e a inclusão ou não de barras de reforço extras nestes furos. / A continuous increase of the use of (steel & concrete) composite structures in constructions can be recently observed. This is mainly due to its faster execution time when compared to other construction alternatives. Additionally, these solutions optimize the structural characteristics of the involved materials: the steel tension capacity and the concrete compressive strength. The transfer of forces between these different materials greatly influences the composite structure performance, where typical solutions uses shear connectors at the concrete to steel interface. The Eurocode 4 defines an experimental test, denominated push-out, to determine the shear connectors strength and associated ductility capacity. Its performance is influenced by the concrete compressive strength, slab dimensions and adopted reinforcing bar area, steel profile dimensions, shear connectors geometry and disposition and by the mechanical characteristics of the connector, profile and reinforcing bars steels. All these aspects indicate that a great number of variables can influence the test. This study presents the development of a finite element model, based on the ANSYS program, to simulate push-out tests. The numerical results presented in this investigation were calibrated against experiments reported in the literature for stud and Perfobond shear connectors. The Perfobond connectors present a substantial shear capacity being influenced by several factors like: connectors hole number and diameter and by the adoption, or not, of extra reinforcing bars passing through the connector holes.