A vibração induzida por escoamento é parte intrínseca do transporte de fluidos. Por exemplo, na indústria de petróleo e gás esse fenômeno pode ser encontrado em tubulações, tanto no setor upstream, quando downstream. Essas vibrações são produto das forças geradas pelo escoamento e, portanto, carregam informações sobre sua fenomenologia. No caso de escoamento bifásico em tubo, resultados experimentais indicam forte influência da velocidade da mistura, fração de vazio e padrão de escoamento no comportamento dinâmico da estrutura. Contudo, pouco foi feito na tentativa de obter informações do escoamento a partir da reposta estrutural. Assim, o objetivo do presente estudo é desenvolver métodos para a previsão dos parâmetros do escoamento baseados na resposta de um tubo submetido a escoamento bifásico. Foi conduzido um trabalho experimental da vibração induzida por diversos padrões gás-líquido numa tubulação horizontal (PVC Ø3/4\'\') duplamente engastada, com água e ar como fluidos de trabalho. A partir de uma abordagem analítica, corroborada com resultados experimentais para escoamento monofásico e bifásico, estabelece-se a existência de uma relação, de natureza quadrática, entre a velocidade de atrito e o desvio padrão da aceleração. Dado que a velocidade de atrito é função do fator de atrito bifásico, um método para a sua previsão é desenvolvido. Ele prevê de maneira precisa os dados coletados; todos eles com erro percentual menor do que 30%. O método foi comparado também com dados experimentais e modelos da literatura, mostrando boa concordância. Além disso, apresenta-se uma relação entre a frequência pico da resposta e a fração de vazio homogênea. No fim, são apresentados: (i) um método de identificação de escoamento pistonado, baseado na superposição dos mecanismos de vibração por turbulência e intermitente, com desempenho mínimo de 81.8%; (ii) um método experimental para determinação da velocidade da mistura (J) e fração de vazio homogênea (β). Os melhores resultados são obtidos para os padrões disperso e pistonado, prevendo adequadamente os parâmetros J e β com erro percentual absoluto médio de 24.1% e 20.65%, respectivamente. / Flow-induced vibration is intrinsic to piping problems. For example, in the oil and gas industry the FIV phenomenon can be found in pipe flow both in upstream and downstream applications. The structural vibration response contains information about the flow phenomenology. In the case of two-phase pipe flow, experimental results show a strong influence of mixture velocity, void fraction and flow pattern on pipe structural dynamics. However, efforts to obtain information of the flow from pipe response have been scanty. The goal of this study is to develop two-phase flow parameters predictive methods based on the structural pipe response. An experimental study of flow-induced vibration was carried out for several flow patterns in a clamp-clamp straight pipe (PVC Ø3/4\'\'), with air and water as working fluids. From an analytical approach, a quadratic relationship between shear velocity and standard deviation of acceleration is proposed and validated against the experimental data of single and two-phase flow. Since the shear velocity depends on the friction factor, a method to predict two-phase friction factor is presented. The method predicts accurately our experimental data with a mean absolute error up to 30%. Good agreement was also found when it was compared with some models and experimental data from the literature. Furthermore, an expression to correlate peak frequency and homogeneous void fraction as a function of added mass is offered. Finally, we present: (i) a slug flow identification technique based on the superposition of the turbulence and intermittent flow-induced vibration mechanisms, with performance of 81.8% and (ii) an experimental methodology to estimate mixture velocity (J) and homogeneous void fraction (β). The latter method shows better agreement for dispersed and slug flow-patterns, predicting J and β with a mean absolute error of 24.1% e 20.65%, respectively.

La mousse de polyuréthane est un matériau cellulaire caractérisé par un spectre de propriétés mécaniques intéressant : une faible densité, une capacité à absorber l’énergie de déformation et une faible raideur.Elle présente également des propriétés telles qu’une excellente isolation thermique et acoustique, une forte absorption des liquides et une diffusion complexe de la lumière. Ce spectre de propriétés fait de la mousse de polyuréthane un des matériaux couramment utilisés dans de nombreuses applications phoniques, thermiques et de confort. Pour contrôler la vibration transmise aux occupants des sièges, plusieurs dispositifs automatiques de régulation et de contrôle sont actuellement en cours de développement tels que les amortisseurs actifs et semi-actifs. La performance de ces derniers dépend bien évidemment de la prédiction des comportements de tous les composants du siège et en particulier la mousse. D’une façon générale, il est indispensable de modéliser le comportement mécanique complexe de la mousse de polyuréthane et d’identifier ses propriétés quasi-statique et dynamiques afin d’optimiser la conception des systèmes incluant la mousse en particulier l’optimisation de l’aspect confort. Dans cette optique, l’objectif principal de cette thèse consiste à implémenter des modèles mécaniques de la mousse de polyuréthane fiables et capables de prévoir sa réponse sous différentes conditions d’essais. Dans la littérature, on retrouve les divers modèles développés tels que les modèles de mémoire entier et fractionnaire. L’inconvénient majeur de ces modèles est lié à la dépendance de leurs paramètres vis-à-vis des conditions d’essais, chose qui affecte le caractère général de leur représentativité des comportements quasi-statique et dynamique de la mousse polyuréthane. Pour pallier à cet inconvénient, nous avons développé des modèles qui, grâce à des choix judicieux de méthodes d’identification, assurent une représentativité plus générale des comportements quasi-statique et dynamique de la mousse polyuréthane. En effet, nous avons démontré qu’on peut exprimer les paramètres dimensionnels des modèles développés par le produit de deux parties indépendantes ; une regroupant les conditions d’essais et une autre définissant les paramètres adimensionnels et invariants qui caractérisent le matériau. Ces résultats ont été obtenus à partir de plusieurs études expérimentales qui ont permis l’appréhension du comportement quasi-statique (à travers des essais de compression unidirectionnelle) et dynamique (à travers des tests en vibration entretenue). La mousse, sous des grandes déformations, présente à la fois un comportement élastique non linéaire et un comportement viscoélastique. En outre, une discrimination entre les modèles développés particulièrement en quasi-statique a été effectuée. Les avantages et les limites de chacun y ont été discutés. / Polyurethane foam is a cellular material characterized by an interesting mechanical spectrum of properties: low density, capacity to absorb the deformation energy and low stiffness. It presents also several other properties, such as excellent thermal and acoustic insulation, high absorption of fluids and a complex scattering of light. This spectrum of properties makes polyurethane foam commonly used in many thermal, acoustic and comfort applications. To control the vibration transmitted to the seat occupants, several automatic devices for regulation and control are currently outstanding developments like active and semi-active dampers. The performance of these devices depends, of course, on the prediction of the behaviour of all the seat components and especially foam. Generally, it is essential to model the complex mechanical behaviour of polyurethane foam and identify its quasi-staticand dynamicproperties in order to optimize the design of systems with foam particularly the optimization of the comfort aspect. In this mind, the main goal of this thesis is to implement mechanical models of polyurethane foam reliable and able to provide its response under different test conditions. Several models has been developed in literature such as memory fractional and integer models. The main disadvantage of these models is the dependence of their parameters against the test conditions. It affects the general character of their representativeness to the quasi-static and dynamic behaviours of polyurethane foam. To solve this problem, we developed models with specific identification methods to ensure broader representation of the quasi-static and dynamic behaviour of polyurethane foam. Indeed, we have demonstrated that we can express the dimensional parameters of the developed models by the product of two independent parts; the first contain only the test conditions and the second define the dimensionless and invariant parameters that characterize the foam material. The developed models have been establish after several experimental studies allowing the apprehension of the quasi-static behaviour (through unidirectional compression tests) and the dynamic behaviour (through harmonic vibration tests). The polyurethane foam, under large deformations, exhibits a non linear elastic behaviour and viscoelastic behaviour. In addition, discrimination between the models developed especially in quasi-static case has been conducted. The advantages and limitations of each model have been discussed.

Les robots industriels ont évolué fondamentalement ces dernières années pour répondre aux exigences industrielles de machines et mécanismes toujours plus performants. Ceci se traduit aujourd’hui par de nouveaux robots anthropomorphes plus adaptés laissant entrevoir la réalisation de tâches plus complexes et soumis à de fortes sollicitations comme durant l’usinage. L’étude du comportement des robots anthropomorphes, à structures parallèles ou hybrides montre une anisotropie aussi bien cinématique, que dynamique, impactant la précision attendue. Ces travaux de thèse étudient l’intégration des redondances cinématiques qui permettent de pallier en partie ce problème en positionnant au mieux la tâche à réaliser dans un espace de travail compatible avec les capacités attendues. Ces travaux ont permis d’améliorer notre outil d’optimisation et de le tester à la fois sur un modèle Eléments Finis du robot et sur le robot réel. Ainsi, ces travaux de thèse apportent des contributions à : - la définition de critères adaptés à la réalisation de tâches complexes et sollicitantes pour la gestion des redondances cinématiques ; - l’identification du comportement des structures sous sollicitations par moyen métrologique (Laser tracker) ; - l’optimisation du comportement permettant l’amélioration de la qualité de réalisation des opérations d’usinage ; - la modélisation Eléments Finis des robots prenant en compte l’identification des rigidités des corps et articulaires. / Industrial robots have evolved fundamentally in recent years to reach the industrial requirements. We now find more suitable anthropomorphic robots leading to the realization of more complex tasks like deformable objects cutting such as meat cutting or constrained to high loading like during machining. The behavior study of anthropomorphic robots, parallel or hybrid one highlights a kinematic and dynamic anisotropy, which impacts the expected accuracy.This thesis studied the integration of the kinematic redundancy that can partially overcome this problem by well setting the task to achieve it in a space compatible with the expected capacity.This work helped us to improve our optimization tool and to try it on both FE model of the robot and real robot.Thus, the thesis makes contributions to: - the definition of criteria adapted to the realization of complex and under high loading task for the management of the kinematic redundancy; - the structural behavior identification, under loading, by metrology tools (Laser tracker) ; - the behavior optimization to improve the cutting process quality during machining ; - robots finite elements modeling using stiffness identification for both bodies and joints.

A vibração induzida por escoamento é parte intrínseca do transporte de fluidos. Por exemplo, na indústria de petróleo e gás esse fenômeno pode ser encontrado em tubulações, tanto no setor upstream, quando downstream. Essas vibrações são produto das forças geradas pelo escoamento e, portanto, carregam informações sobre sua fenomenologia. No caso de escoamento bifásico em tubo, resultados experimentais indicam forte influência da velocidade da mistura, fração de vazio e padrão de escoamento no comportamento dinâmico da estrutura. Contudo, pouco foi feito na tentativa de obter informações do escoamento a partir da reposta estrutural. Assim, o objetivo do presente estudo é desenvolver métodos para a previsão dos parâmetros do escoamento baseados na resposta de um tubo submetido a escoamento bifásico. Foi conduzido um trabalho experimental da vibração induzida por diversos padrões gás-líquido numa tubulação horizontal (PVC Ø3/4\'\') duplamente engastada, com água e ar como fluidos de trabalho. A partir de uma abordagem analítica, corroborada com resultados experimentais para escoamento monofásico e bifásico, estabelece-se a existência de uma relação, de natureza quadrática, entre a velocidade de atrito e o desvio padrão da aceleração. Dado que a velocidade de atrito é função do fator de atrito bifásico, um método para a sua previsão é desenvolvido. Ele prevê de maneira precisa os dados coletados; todos eles com erro percentual menor do que 30%. O método foi comparado também com dados experimentais e modelos da literatura, mostrando boa concordância. Além disso, apresenta-se uma relação entre a frequência pico da resposta e a fração de vazio homogênea. No fim, são apresentados: (i) um método de identificação de escoamento pistonado, baseado na superposição dos mecanismos de vibração por turbulência e intermitente, com desempenho mínimo de 81.8%; (ii) um método experimental para determinação da velocidade da mistura (J) e fração de vazio homogênea (β). Os melhores resultados são obtidos para os padrões disperso e pistonado, prevendo adequadamente os parâmetros J e β com erro percentual absoluto médio de 24.1% e 20.65%, respectivamente. / Flow-induced vibration is intrinsic to piping problems. For example, in the oil and gas industry the FIV phenomenon can be found in pipe flow both in upstream and downstream applications. The structural vibration response contains information about the flow phenomenology. In the case of two-phase pipe flow, experimental results show a strong influence of mixture velocity, void fraction and flow pattern on pipe structural dynamics. However, efforts to obtain information of the flow from pipe response have been scanty. The goal of this study is to develop two-phase flow parameters predictive methods based on the structural pipe response. An experimental study of flow-induced vibration was carried out for several flow patterns in a clamp-clamp straight pipe (PVC Ø3/4\'\'), with air and water as working fluids. From an analytical approach, a quadratic relationship between shear velocity and standard deviation of acceleration is proposed and validated against the experimental data of single and two-phase flow. Since the shear velocity depends on the friction factor, a method to predict two-phase friction factor is presented. The method predicts accurately our experimental data with a mean absolute error up to 30%. Good agreement was also found when it was compared with some models and experimental data from the literature. Furthermore, an expression to correlate peak frequency and homogeneous void fraction as a function of added mass is offered. Finally, we present: (i) a slug flow identification technique based on the superposition of the turbulence and intermittent flow-induced vibration mechanisms, with performance of 81.8% and (ii) an experimental methodology to estimate mixture velocity (J) and homogeneous void fraction (β). The latter method shows better agreement for dispersed and slug flow-patterns, predicting J and β with a mean absolute error of 24.1% e 20.65%, respectively.

Today is the implantation of joint replacements, although a radical, but very functional restoration frequent way ill joint. The implants are placed high demands on their biocompatible and long-term function, which is directly related to wear of joint replacements in the human body. Therefore, analysis of the complex behavior of the implant in the human body is a fundamental problem of biomechanics of implants. This issue is dedicated, this dissertation thesis. Dissertation thesis deals with the solution design and development of experimental device for testing the TEP acetabula and wear identification using optical method. The proposed device allows the joint burden hole TEP physiological manner, but by working with the acetabulum burdened by Power resultant joint axis passes through the hole. The physiological loading of articular wells and evaluating the size of the loss of polyethylene is currently intensively addressed. The results of this study may in the near future, serving as information for assessing the conduct of wear prosthetic hip joint in vivo. The work is devoted to solving the problem of the size required to detect the loss of polyethylene for joint replacement arthroplasty: Design and development of experimental equipment for testing the acetabulum of the hip joint arthroplasty. Identify wear using optical methods. Design and development of experimental equipment was made in the system Inventor Professional 2010 at the level of 3D modeling. Great attention was paid to the design fit into the acetabulum TEP testing machines and gripping the acetabulum into an optical device. Management options were tested with combinations of experimental equipment engines. Suggestions were made and then tests for fixing the acetabulum into an optical device. Has the possibility of depth analysis and identification of wear joined with innovative solutions to evaluate the loss of polyethylene acetabulum arthroplasty. Identification of abrasion (loss of polyethylene) joint arthroplasty holes were carried out experimental measurements using an optical holographic interferometry. The comprehensive analysis of the results of experimental measurement of the loss of polyethylene shows that this method can identify both the size but also an area where there is even to small changes in the surface, which depend on the abrasion. One can also say that using this method we are able to affect the will or displacements that affect the size of the loss of polyethylene in joint arthroplasty hole. Despite the number of known and lessons learned arising from the results of solving the problem of design and development of experimental equipment for testing the acetabulum and hip arthroplasty wear identification using optical methods, this work is that the initial study to identify problematics wear of joint replacements. Complete resolution of this issue is beyond the scope of one doctoral thesis.

Today, the use of one's bank card to pay or withdraw money is common. Modern technology provides us with the convenience of instant transactions at the automated teller machine or point of sale but unfortunately, it has also brought the reality and risk of card skimming and counterfeit card fraud. Criminals have become very efficient and technologically advanced in skimming and counterfeiting cards, to such an extent that counterfeit card fraud has become a significant threat to the public, banking, retail and business in South Africa. Counterfeit card fraud is a complex, multi-faceted crime, requiring specific skills and knowledge of card counterfeiting methods from police and bank investigators. The scope of its investigation is wide. It includes different crime scenes and offenders, sophisticated equipment and various aspects that need to be identified positively. Investigators find it difficult to identify perpetrators and certain aspects unique to this crime and, as a result, many investigations are unsuccessful. This research endeavours to establish what identification methods are available to investigators and which are effective. / Police Practice / M. Tech. (Forensic Investigation)