Projeto de um dispositivo para prensar bobinas polares de pólos salientes para hidrogeradores

The increasing demand for productivity and quality in companies has converged to a common point: reducing costs. In this context the present work aims at the development of a mechanical press which is designed for pressing polar hydrogenerators coils with salient pole in field facilitating the assembly of the poles in the plant, as well as reforms especially in hydrogenerators, reducing significantly the transport costs. With security in mind as well as reduced costs, a study was made of the materials to be used as it was applied a methodology for calculating the correct choice of safety factor to be used in the device. Through mechanical calculations were dimensioned critical items of the device as the diameter of the rods as well as the minimum thickness of the base of the device must have so that it does not break threaded shear in the region by applying the total load of traction on the risers implementation of the pressing. All compression loading device will be through the application of torque on the nuts of bolts in this way was defined by calculations the required torque for each nut so that you can reach the pressure specified in the design specifies. The modeling of the device was made using the INVENTOR™ program in conjunction with the program ANSYS ™. These programs have created designs in three dimensions, assembly and simulation of stress analysis in components of the device

Avaliação das condições de contorno da teoria de Hertz, comparando os resultados analíticos e numéricos a partir de simulações em software de elementos finitos

The objective of this study was to present the comparison between analytical and numerical results trying to identify the differences and behaviors of the variation of the principal stresses and the maximum contact pressure for different model configurations. The analytical equations of the theory of Hertz from the boundary conditions adopted by him were differences are shown. A step-by-step of developing the model indicating the geometric dimensions, surface contact, type of contact, the formulation used by the software, type of mesh, as well as the boundary conditions and load was presented. In the results, the stresses calculated analytically and compared with the stresses obtained by the finite element simulation software indicating the changes have been made

Alterações na dinâmica de colônias de Atta sexdens rubropillosa Forel, 1906 (Hymenoptera: Formicidae) submetidas ao tratamento com iscas tóxicas

As formigas cortadeiras são consideradas pragas por causarem diversos prejuízos em áreas agrícolas e, por este motivo, há um crescente interesse em métodos variados de controle destes insetos. Atualmente, existem diversos métodos de controle conhecidos, mas o mais utilizado é o controle químico, que apresenta diferentes estratégias de formulação e modos de aplicação. O principal método químico utilizado são as iscas tóxicas, que tem a melhor eficiência e já são utilizadas em escala comercial. O presente trabalho teve como objetivo avaliar as alterações que ocorrem na dinâmica de colônias de Atta sexdens rubropilosa Forel, 1906 (Hymenoptera: Formicidae) submetidas ao tratamento com iscas tóxicas contendo os ingredientes ativos sulfluramida e hidrametilnona, as quais serão comparadas com uma colônia controle, que receberá isca sem ingrediente ativo. Para isso, foram utilizadas três colônias de A. s. rubropilosa, mantidas em laboratório, com aproximadamente 1000 mL de jardim de fungo cada. Elas foram dispostas em vitrais, interligados a dois potes plásticos, um para a câmara de forrageamento e outro para o lixo. Um dia antes de iniciar o experimento, todo o lixo foi retirado e as colônias foram deixadas sem o fornecimento de alimento. Após 24 horas sem alimentação, as iscas foram oferecidas na câmara de forrageamento de cada colônia. A colônia 1 recebeu 3g de isca sem ingrediente ativo; a colônia 2 recebeu 3g de isca contendo sulfluramida; e a colônia 3 recebeu 3g de isca contendo hidrametilnona. Durante 10 dias, foram avaliados aspectos como carregamento, incorporação e devolução das iscas, alterações comportamentais das operárias classificadas como sintomas de intoxicação, mudanças no aspecto físico dos jardins de fungo, como umidade e aparecimento de fungos contaminantes, e a extinção da colônia. A partir dos dados obtidos, foram feitas análises comparativas das atividades comportamentais...

Análise estatística da vida em fadiga de compósitos estruturais pela distribuição de Weibull

Nowadays technological trend is based on finding materials that could support low weight with satisfactory mechanical properties and for this reason composite material became a very attractive topic in research projects all over the world. Due to its heterogenic properties, this type of material shows scatter in mechanical test results, especially in cyclic loading. Therefore it is important to predict its fatigue strength behaviour by statistic analysis, once fatigue causes approximately 90% of the failure in structural components. The present work aimed to investigate the fatigue behaviour of the Twill/Cycom 890 composite, which is carbon fiber reinforced with polymeric resin as matrix and manufactured via RTM process (Resin Transfer Molding). All samples were tested in different tensile level in triplicate in order to associate these values. The statistical analysis was conducted with Two-Parameter Weibull Distribution and then evaluated the fatigue life results for the composite. Weibull graphics were used to determine the scale and shape parameters. The S-N curve for the Twill/Cycom composite was drawn and indicated the number of cycles to occur the first damages in this material. The probability of failure was associated with material reliability, as shown in graphics for the different tensile levels and fatigue life. In addition, the laminate was evaluated by ultrasonic inspection showing a regular impregnation. The fractographic analysis conducted by SEM showed failure mechanisms for polymeric composites associated to cyclic loadings ... (Complete abstract click electronic access below)

Fractografia quantitativa e o conceito de tenacidade à fratura para a análise do efeitodo choque térmicos em TiO2

The present study evaluated the use of semicircular bending test (SCB) as an alternative to conventional bending test to examine the effect of thermal shock. Still, studies the behavior of fracture surfaces generated by monofractal behavior analysis, which allows us to evaluate the contributions of the microstructure and the mechanical context in forming reliefs during the crack propagation. The fractal analysis is made from elevation maps obtained by reconstruction method by extension of the focus stacks of digital images acquired in microscope. The specimens used were samples semicircular pressed TiO2 (rutile) with and without heat shock, prepared for testing mode I loading. Were also produced, specimens in the form of bars for Weibull statistical analysis. From the three-point bending test, we found the variation of fracture toughness between the samples after the heat shock and natural condition. The SCB test was feasible for the analysis of thermal shock resistance. The results showed that the value of the fracture toughness decreases as the heat shock treatment

Análise dos efeitos das deformações estruturais sobre a transferência transversal de carga em um veículo do tipo fórmula SAE submetido a uma aceleração lateral constante

This paper studies the frame deformations on a formula SAE vehicle in steady-state cornering and its influence on the lateral load transfers and, consequently, on the tires normal loads due to the applied lateral load. For a vehicle with a perfect rigid frame, the vehicle mass, the position of the center of gravity and the suspensions are the only factors responsible for the load distribution between the tires. When the frame deformations are no longer negligible, the frame deformations affect the loaddistribution between the tires. The frame flexibility turns it able to behave as an additional set of springs to the suspension system, thus changing the behavior of the set. This paper describes howit happens and suggests ways to minimize this phenomenon

Análise de falhas por fadiga de alto ciclo em eixos de transmissão utilizando o método dos elementos finitos

This work presents a study that aims to validate the fatigue analyses developed on finite element commercial software, ANSYS Workbench. It was based on mechanical tests development of traction and hardness, to verify the mechanical properties of material that the shaft was manufactured (ABNT 1045 steel), it was developed bend test, with purpose to prove the confiability degree of computational analyses, obtaining the maximum stress in a work condition determined with 40 [kgf] of load applied, and at the end, was developed the fatigue test to obtain the number of cycles that the transmission shaft can support in a work condition with 8 [kgf] of load applied. The results obtained during the work present, have to be quite satisfactory with the theoretically expected

Musuko: os filhos da miscigenação

This project is about a book-report, which will discuss the nipo-brazilian’s identity. The Kasato-Maru ship arrived at Santos about a hundred years ago, opening a path that would never be closed: the path between Japan and Brazil, countries both geographically and culturally opposite. Miscegenation brings the nipo-brazilian to life, a individual who does not feel entirely Brazilian or Japanese. The goal of the book is to discuss the nipo-brazilian’s identity, once known that this individual can adopt one or other culture, or even merge both. It is not intended to conclude anything, so the main objective fulfills itself in the research of the possibilities of identities through interviews, theories, Japanese immigration’s history and Brazilian’s culture

Estudo, desenvolvimento e concepção de uma célula de carga

In engineering projects, it’s fundamental to determine the active loads in components in order to guarantee acceptable values of safety and reliability according to project specifications. On the other hand, force measurement methods might be very complex and impracticable in some cases and, so that, load cells with eletric resistance strain gages can be applied as a simple and accurate option to measure the required load. The main purpose of this paper is to present the development of a load cell that measures uniaxial forces using electric resistance strain gages without being influenced by the location of the loading in a cantilever beam. For that, it was taken as basis a secondary purpose which is to present a general study of basic and wide concepts about transducers, load cells and extensometers primarily. Information such as: loading and measurements types, characteristics of the presented devices as well as factors that influence its functioning, the most common kinds of Wheatstone bridge links, the main points of a load cell project, cements used to fix extensometers and, finally, the project itself with the tests of the built transducer are presented. By the end of this paper, all the results are shown and analyzed, concluding about the designed load cell and the work itself

Desenvolvimento de um smart meter: um estudo sobre eficiência energética através das redes inteligentes

Pós-graduação em Engenharia Elétrica - FEB

Análise de fadiga em rodas automotivas utilizando método dos elementos finitos

The increasing search for better performance at the automotive industry, especially on the matter of fuel consumption, caused a progressive evolution of industrial technology. For the wheel this study is based on the try of reducing mass and decreasing the moment of inertia, characteristics that directly reflect on the performance parameter, as consumption and acceleration, so that it also is effective on the growth of the profit margin, since it reduces the costs of the locomotion. In this paper will be applied the Finite Element Analysis to explain the wheel behavior and identify ways to improve the performance. To the analyze it will be simulated a test condition established by ABNT NBR 6751:2009 foreseeing a possible collapse through general yielding and fatigue. The load here presented results from the equation presented on the norms and in the datas provided by the manufacturer

Fadiga em compósitos 5HS carbono/epóxi processados via RTM: relação entre cargas axiais no plano e modos de delaminação

Pós-graduação em Engenharia Mecânica - FEG

Estudo da fadiga em liga de alumínio aeronáutico 7475-T761

This work will address the study of fatigue conditions with constant load in an alloy of aluminum analysis 7475 - T761, so we can better understand the conditions of the aircrafts which contain this alloy in their structures. A literature review, which was discussed the concepts of fracture mechanics, fatigue, aeronautical components, chemical analysis of aluminum alloys, fatigue problems that appears in the aircrafts, metallographic analysis, and testing of optical microscopy tensile, fatigue and microhardness, surface analysis (MEV) study of the chemical composition of the alloy in question, the main causes of crashes, was performed, completing the work, analysis of data from tensile test, hardness and fatigue together with the interpretation of images of optical microscopy and scanning electron was taken. The data indicated the high mechanical strength of the alloy, along with its microstructure indicating elongated grains and high surface contour, which shows such resistance by hindering the movement of dislocations. The grooves are clearly shown in the MEV images as well as the classic with increased fatigue loading and subsequent reduction of the number of cycles to rupture behavior shown in the graphs. Therefore we observed the optimal behavior is supported by the league when subjected to fatigue loadings

Estudo do comportamento em fadiga de um tubo de aço microligado, grau API 5L X70

This work focuses on a study on the fatigue behavior of a microalloyed steel API 5L X70, used in pipes lines to transport oil and gas. These types of steels have excellent mechanical resistance values and ductility and therefore increased their study driven by increased demand for oil and especially natural gas, which consequently raises the need to build new pipelines to transport these products. The oil extraction units, composed of the risers (pipelines connecting the oil well to the ship), are dimensioned to remain installed for periods of 20 to 30 years in the marine environment, a hostile environment for high pressure, corrosion, low temperatures and the stresses caused by the movement of water and tides. For analysis, the S-N (stress versus number of cycles) curves were obtained from data collected from bodies-of-proof cylindrical longitudinal, transverse and that one removed from the weld area of the pipe, tested in accordance with ASTM E466. Tensile tests were performed for characterizing the mechanical properties of the samples and welded joints, concluded that the values meet the specifications of the standard API 5L. To characterize microstructural material, also metallographic analysis was made of regions of the base metal and the HAZ. The results of fatigue tests demonstrated a higher life for the specimens removed from the longitudinal direction the pipe, followed by those in the transverse direction and, finally, the welded joint. The origins of the fatigue cracks were determined by scanning electron microscopy (SEM)

Equipamento para realização de ensaios de tração confinada e aquecida em geossintéticos

Pós-graduação em Engenharia Civil - FEIS