Thermal fatigue failure, due to the fracture of solder bumps which was cased by the coefficient of thermal expansion mismatch deformation, is frequently encountered in flip-chip package. Therefore, this thesis attempts to study the effects of geometric parameters variation on lead-free flip-chip package under temperature cycling test. First, we used the finite element method to simulate the thermal loading response of lead-free flip-chip. The accumulated equivalent creep strain and accumulated creep strain energy density of the lead-free solder bumps were calculated, and were used to predict the thermal fatigue life of lead-free flip-chip package. The Taguchi method is applied to obtain the optimal design parameters in order to enhance reliability of the lead-free flip-chip under temperature cycling loading. The analysis of variance (ANOVA) is also used for estimating the influence of the factors quantitatively. The obtained results can be adopted as references for the lead-free flip-chip package design.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / This paper aims to scale, build and test a new vortex tube, operating from the use of compressed air at pressures below the pressure ranges typical of this unconventional cooling device for the purpose of obtaining drafts cold for air conditioning. For that were originally studied theoretical and experimental aspects of flow processes through tests performed in the laboratory with a commercial vortex tube. Known influence of geometric parameters (such as the ratio between the length and internal diameter of the tube and the diameter of the diaphragm hole) and the thermophysical properties (such as inlet pressure gauge in the compressed air tube and the mass flow rate of the stream cold) air in the performance of the vortex tube, gave up the step of sizing the same. After engineered and designed parts of the tube, the final steps were the manufacture of pipe and conducting experimental tests, beyond the selection of a photovoltaic array to provide the power required to drive the compressor. The results of the laboratory tests with a vortex tube counter-current type, internal diameter D equal to 16.5 mm and a length equal to fifteen times this value, and configured diaphragm orifice diameter of 0.5D showed that temperatures of the cold air flow of 9.5 ÂC at a mass flow of 40% of the mass flow input are obtained when delivered by the compressor inlet gauge pressure of 3 bar and volumetric flow rate of 3.15 L/s compressed air. / O presente trabalho tem como objetivos dimensionar, construir e testar um novo tubo de vÃrtice, que opere a partir da utilizaÃÃo de ar comprimido em pressÃes abaixo das faixas de pressÃo tÃpicas deste dispositivo de refrigeraÃÃo nÃo-convencional, com o propÃsito de obter correntes de ar frio para climatizaÃÃo. Para tanto, foram inicialmente estudados aspectos teÃrico-experimentais dos processos de escoamento, atravÃs de testes realizados em laboratÃrio com um tubo de vÃrtice comercial. Conhecida a influÃncia dos parÃmetros geomÃtricos (tais como a razÃo entre o comprimento e diÃmetro interno do tubo e o diÃmetro do orifÃcio do diafragma) e das propriedades termofÃsicas (tais como a pressÃo manomÃtrica de entrada no tubo do ar comprimido e o percentual de vazÃo mÃssica da corrente de ar frio) no desempenho do tubo de vÃrtice, deu-se a etapa de dimensionamento do mesmo. Depois de projetadas e desenhadas as peÃas do tubo, as etapas finais foram a fabricaÃÃo do tubo e a realizaÃÃo de testes experimentais, alÃm da seleÃÃo de um arranjo fotovoltaico que forneÃa a potÃncia necessÃria para o acionamento do compressor. Os resultados dos testes em laboratÃrio com um tubo de vÃrtice do tipo contra-corrente, de diÃmetro interno D igual 16,5 mm e comprimento igual a quinze vezes esse valor, e configurado com diafragma de diÃmetro do orifÃcio de 0,5D, mostraram que sÃo obtidas temperaturas da corrente de ar frio de 9,5 ÂC a uma vazÃo mÃssica de 40% da vazÃo mÃssica de entrada, quando fornecido pelo compressor pressÃo manomÃtrica de entrada de 3 bar e vazÃo volumÃtrica de 3,15 L/s de ar comprimido.

Blasting is one of the most important stages in the productive process of a mine due to its direct impact on rock fragmentation, which determines the degree of productivity of operations and the extraction costs generated. In this scenario, an optimized methodology is presented for designing blasting meshes by using mathematical models that help calculate the geometric parameters of a blasting mesh, such as burden, considering the variables of the rock mass and the type of explosive to measure its impact on rock fragmentation and loading productivity (tons/hour). The main advantage of this method is the reliability of the design, which takes into account a greater number of variables that influence fragmentation and uses the principle of distribution and amount of energy in an optimal way. The results obtained in the case of application show that a change in design (2.7 x 2.7 square mesh to 2.2 x 2.5 triangular mesh) reduces P80 by 65%, from 17 to 6 inches, approximately. Additionally, the results show that greater operational efficiency was achieved by increasing excavator productivity by approximately 15.6%.

The aim of diploma thesis is design of new connection in Havlickuv Brod. New connection will enable passage without setting-back between Brno and Jihlava in Havlickuv Brod.

Lors de l'optimisation géométrique de structures, un grand nombre d'évaluations de champs est nécessaire. L'idée, développée dans cette thèse, est la construction efficace et rapide d'approximations de ces champs à travers la Proper Generalized Decomposition (PGD), une méthode de réduction de modèle. Les résultats, calculés une fois pour toutes, sont stockés dans des abaques virtuels pour une utilisation ultérieure dans un processus d'optimisation. Le problème considéré est paramétrique et les paramètres définissent la géométrie. Ce type de problème est particulièrement adapté à la PGD. En effet, de nombreux travaux ont traité de la résolution de problèmes paramétriques et des premières études ont porté, en particulier, sur la prise en compte de paramètres géométriques. Toutefois, ce qui caractérise nos travaux est d'aller vers des outils aptes à traiter des situations significatives de la complexité des problèmes rencontrés au niveau industriel. En particulier, l'exploitation de codes éléments finis commerciaux est une contrainte majeure. Il a été décidé de développer des méthodes permettant de traiter des problèmes à paramètres géométriques par la PGD, et, en partenariat avec AIRBUS Defence & Space, d'appliquer ces techniques à un démonstrateur industriel présentant une géométrie complexe (type splines) et de fortes non-linéarités (géométriques, matériaux). Notre démarche a été implémentée dans un process industriel utilisant des codes éléments finis commerciaux. On propose aussi une nouvelle extension de la PGD aux paramètres discrets autorisant la prise en considération, dans une même résolution, de configurations de structures complètement différentes (cas de chargement, matériaux, etc.). / During shape optimisation of structures, numerous evaluations of fiels are necessary. The idea, developed in this PhD thesis, is the efficient construction of approximations of these fiels through the Proper Generalized Decomposition (PGD), a model reduction technique. The results, computed once and for all, are stored in virtual charts for a subsequent use into an optimisation process. Geometry variations correspond to a parametric problem, where the parameters is the geometry. This kind of problem is well suited for PGD. Many studies dealt with the resolution of parametric problems and recent works treated, particularly, the introduction of geometric parameters. However, our approach is to deal with configurations of the complexity of industrial problems. The use of commercial finite elements software is a crucial issue. It was decided, in partnership with AIRBUS Defence & Space, to develop techniques allowing the resolution of geometrically parametrised problems thanks to PGD and to apply them to an industrial demonstrator. The geometry considered is defined by splines and the behaviour of the structure is highly non-linear (geometric and material non-linearities). The approach was implemented into a genuine industrial design process using commercial finite elements software. The thesis proposed, also, a new extension of PGD to discrete parameters. It allows to take into account completely different configurations (loadings, materials, etc.) in the same resolution.

Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-07-08T14:34:31Z No. of bitstreams: 1 Matheus Vicenzo Lehnen.pdf: 7507080 bytes, checksum: 1036a30adcb3840ea0e5fcb545f29987 (MD5) / Made available in DSpace on 2015-07-08T14:34:31Z (GMT). No. of bitstreams: 1 Matheus Vicenzo Lehnen.pdf: 7507080 bytes, checksum: 1036a30adcb3840ea0e5fcb545f29987 (MD5) Previous issue date: 2012-05 / Milton Valente / Nos dias atuais, os componentes eletrônicos estão cada vez mais potentes e com mais dispositivos integrados e há a necessidade de uma dissipação térmica mais eficiente. Os atuais ventiladores e dissipadores de calor usando ar como fluido de trabalho estão ficando obsoletos. Por este motivo, torna-se necessário o desenvolvimento de um sistema mais eficiente. Existem três técnicas principais em estudo nesta área: resfriamento líquido, trocadores de calor compostos por microcanais e jatos sintéticos como transmissores de quantidade de movimento ao fluido. Entretanto, a análise em pequena escala encontra limitações experimentais de modo que uma abordagem por Dinamica de Fluidos Computacional (Computational Fluid Dynamics – CFD) é mais recomendável para caracterizar e validar o desempenho dos jatos sintéticos. O objetivo principal deste trabalho é realizar uma análise fluidodinâmica de jatos sintéticos e caracterizar a troca térmica de jatos sintéticos colidindo sobre uma superfície aquecida, através de simulação numérica. A flexibilidade da aproximação numérica também possibilita o estudo da sensibilidade do design a vários parâmetros físicos e geométricos, tais como o número de Reynolds, a frequência do atuador, o número de Prandtl, a distância da placa aquecida ao orifício da cavidade, o formato do orifício do atuador, a profundidade da cavidade e a espessura da placa do orifício. Os resultados caracterizam o efeito dos parâmetros físicos e geométricos de interesse na formação do jato e na dissipação térmica. O conhecimento agregado neste estudo permitiu determinar uma correlação para o número de Nusselt em função da frequência adimensional – o número de Strouhal – do número de Reynolds, do número de Prandtl e da distância adimensional da superfície aquecida ao orifício. Assim, é possível prever o comportamento de tais jatos sobre a superfície aquecida, e assim contribuir para os atuais estudos nesta linha de pesquisa. Os resultados apresentados tem então aplicação em estudos posteriores, de maior complexidade de design com atuadores combinados com trocadores de calor de aletas, coolers e micro canais, resultando em avanços na área de resfriamento de microchips. / Current electronic components are becoming ever more potent and densly integrated, which requires further increases in the efficiency of heat dissipation. With current fan-based heat dissipation techniques with air as the working fluid becoming outdated, there is a pressing need to develop more eficient methods to cope with demand. So far, three techniques have been the primary focus of studies in this area: liquid cooling, microchannel heat exchangers and synthetic jets used to promote increased momentum transfer. Analysis of such devices at the small physical scale of electronic components is somewhat problematic in experimental form so that a computational fluid dynamics (CFD) approach is recommended. The main objective of this study is thus to utilize a CFD approach to establish the performance characteristics of a synthetic jet impacting against a heated surface. The flexibility of a numerical approach also allows the examination of the sensibility of the design with respect to several physycal and geometric parameters such as Reynolds number, pulsing frequency, jet orifice shape and size, cavity size and distance between the heated surface and the device. Such results, provide insight in the effect of physical and geometric parameters in the jet formation and heat dissipation. The combined knowledge of this study allowed the development of a practical correlation for the Nusselt number based on the Strouhal number (normalized pulsing frequency), Reynolds number, Prandtl number and the distance between the heated surface and the synthetic jet. This result allows improved predictions of a jet impacting against a heated surface and, consequently, adds an important contribution to other studies in this area. It is expected that the results presented here will be the starting point for further work, in which increasingly complex geometries such as actuators combined with heat exchangers equipped with fins, coolers or microchannels are examined to further improve the knowledge in the field of electronic cooling.

The aim of the work is to compare different ways of measuring geometric parametrs of railway track and compare methods for guidance automatic tamping machine in estabilishing the geometrical parameters of the selected track section between train stations Brodek u Přerova - Grygov. The work contains a description of the superstructure gauging carriage and measuring system APK, whose data were used to compare the track geometry and its spatial position during the observation period. Conclusion of the work includes an assessement of individual measurements and recommendations for practise.

The aim is design of Ledeč nad Sázavou railway station renovation. This renovation has to satisfied current traffic and valid legislation, especially entrance for persons with reduced mobility. There is the new platform at Chotěboř railway station according to current legislation. Change of trackage was in a very small way.

The main theme of this master thesis is the design of technological process measurement and processing of measured data entered crane tracks to determine the geometric parameters of these crane tracks. Diploma thesis further describes the procedure for testing and possible rectification surveying equipment and instrumentation. The thesis is divided of 7 parts, contains 31 images, 4 graphs, 44 tables and 13 attachments. The theoretical part of this thesis contains information about several types of cranes, methods of measurement and processing, as well information on legal and technical regulations related to this topic of the thesis. The fourth and fifth parts of this thesis provides information on selected crane tracks on which the measurements were taken, the choice of methods of measurement, processing technique and the results obtained. The final part of the thesis includes evaluation of the results obtained, comparing methods of measurement, processing, evaluation and design of a technique of determining the geometric parameters of crane tracks.