Caracterização microestrutural e mecânica de trilhos ferroviários soldados de topo por caldeamento

Pós-graduação em Engenharia Mecânica - FEIS

As peças didáticas de Bertolt Brecht e o processo de alfabetização

Pós-graduação em Educação - IBRC

Análise da falha do suporte de mancal de um eixo cardan utilizado num veículo pesado

Pós-graduação em Engenharia Mecânica - FEG

Avaliação da tenacidade CHARPY-V de um tubo de aço API 5L X70 soldado com arco submerso

This research project focused primarily on assessing the impact toughness of the weld and the base material of a steel pipe API 5L X70 submerged arc welded, used to conduct remote oil and gas (linepipes). The analysis followed strictly the Specification for Line Pipe - API 5L Standard, regarding the removal of the specimens of regions-of-proof-long section of the pipe, at 90o and 180o from the welded joint, and mechanical properties of toughness and Charpy-V, both the joint welded as the base material. Specimens of steel tube supplied by Tenaris Confab-SA were sized for tensile and Charpy-V, according to ASTM E 8M and ASTM E23, respectively. The result obtained showed that the API X70 steel tube has high Charpy-V toughness, near to each other at both 90o and 180o from the welded joint of the tube, and both higher than the weld metal. Microstructural and microhardness analysis complemented the present study

Determinação do fator de rigidez de junta aparafusada em tração utilizando o software Excel

When a bolted joint is loaded in tension with dynamically, part of this load is absorbed by the bolt and rest is absorbed by the joint material. What determines the portion that is to absorbed by the bolt is the joint stiffness factor. This factor influences the tension which corresponds to pre-load and the safety factor for fatigue failure, thus being an important factor in the design of bolted joints. In this work, three methods of calculating the stiffness factor are compared through a spreadsheet in Excel software. The ratio of initial pre-load and the safety factor for fatigue failure depending on the stiffness factor graph is generated. The calculations for each method show results with a small difference. It is therefore recommended that each project case is analyzed, and depending on its conditions and the range of stiffness values, the more or less rigid method about the safety factor for fatigue failure is chosen. In general, the approximation method provides consistent results and can be easily calculated

O programa Bolsa Família: comparação entre as regiões Nordeste e Sudeste

This paper has as goal to analyze the Bolsa Família program in its several aspects (creation, discussions about it, perspective of those who receives the program benefits, its reach and effectiveness in comparison with what had been idealized by its creators). Besides that, it is done a report since the colonization age until the period before the creation of the social assistance programs to justify the inequality that the country are currently in, and, like it is made clear during the mentioned research, it has been improved in the course of years. And finally, it is proved through statistics the inequality between Northeast and Southeast regions. They represent, together, the biggest part of Brazilian population e their socioeconomics problems, in a way that can be taken into consideration as an example to the rest of the country

Investigação experimental da tenacidade em tubos de aço API 5L X70 soldados pelo processo HF/ERW

Studies about structural integrity are very important when it desires to prevent disasters associated with flaws inherent in materials used in structural components. The welded joints in steel pipes used to conduction and distribution of oil and gas correspond to the regions most susceptible to flaw. Aiming to contribute to this research line, the present study was designed to assess experimentally the structural integrity of welded joints in steel pipes API 5L X70 used in pipeline systems. This assessment is given from tests of CTOD, whose aim is simulate in laboratory the real behaviour of crack from of his propagation on the welded joint obtained by high frequency electric resistance welding. In this case, the analyses are performed from specimens SE(B) obtained directly of steel pipe API 5L X70. The proposed methodology involves tests of CTOD at lower temperature, in order to assess the toughness of material in critical operation conditions. From performance of CTOD tests, was possible assess the toughness of welded joints in terms of quantity through CTOD parameter and in terms of quality from behaviour of curve load versus CMOD. In this study, also, sought to compare CTOD’s results obtained through rules ASTM E1820 (2008) and BS 7448 (1991). Although the two standards cited previously have adopted different parameters to calculated the value of CTOD, concluded that the values of CTOD tend to converge for a common value

Análise microestrutural de tubos API P110, para prospecção de petróleo e gás, soldados pelo processo HF/ERW

On the grounds of the great advances achieved over recent years, the process HF/ERW (High-Frequency/Electric Resistance Welding)welded pipe have played an active role in the oil and gas industry for deep water applications, at high and extremely low temperatures, under high pressure and in highly corrosive environments, gradually replacing manufactured pipes by other processes. However, studies have shown that defects in the welded joints are a the leading causes of pipelines failures, which has required the determination of toughness values in this region, in compliance with the strict recommendations of the codes and standards with manufacturers and construction companies, on the oil and gas sector. As part of the validation process required toughness values, this research project focuses on a microstructural analysis in HF / ERW tubes microalloyed, steel grade API 5CT P110, designed to explore oil and gas in deep waters, the subject of strategic relevance to the country because of the recent discoveries in the Santos mega fields: Tupi and Libra (pre-salt). In this scientific work will be presented and discussed the results of mechanical tensile and Charpy, a few CTOD tests curves (showing the trend of toughness values to be obtained), and the microstructures of the base material obtained by optical microscopy, with special emphasis on the formation of nonmetallic inclusions in the welded joint

Dinâmica da vegetação de uma floresta paludosa no município de Rio Claro - SP

Swamp forests, are laid down in the lowlands, with almost permanent presence of water on the soil surface and generally occupy portions fairly flat. In 2003 a phytosociological survey was conducted of the tree and shrub component of a swamp forest established on a steep slope in Rio Claro - SP, through the use of 45 permanent plots of 10 mx 10 m (0.45 ha) divided into three blocks: 1, 2 and 3. The present study aimed to review these plots and discuss the dynamics of vegetation in the swamp forest in question period of eight years. Altogether 1529 individuals were found alive, belonging to 29 families and 47 species. It can be observed that there was a decrease of one family (Flacourtiaceae) and two species (Xylosma tweediana, Inga marginata) in relation to 2003. In general there was a loss not only in number of individuals, but basal area and species diversity. The Block 1 was the only one to show a positive balance in terms of numbers of individuals (2.75%); in Block 2, there was little variation (1.72%) which is negative; whereas Block 3 had the largest decrease, 19.18%. The mortality rate (2.74% / year) for the community remained higher than the recruitment (1.81% / year). There was a decrease (3.19%) of total basal area of the sample relative to 2003, with the highest relative dominance by Calophyllum brasiliense. The decline in diversity of species could be evidenced by the Shannon index, which was 2.0 nats.individual-1 and evenness of 0.52. The most important species (IVI) were Euterpe edulis, Calophyllum brasiliense and Magnolia ovata, together accounting for 59% of IVI community. High mortality and low recruitment rates indicate disturbances in the community, some factors such as proximity to roads, the different soil types associated with a high rate of water saturation and the declivity are crucial to the balance within the community

Caracterização microestrutural de uma estrutura tubular aeronáutica submetida a sucessivos reparos de solda TIG

This work examines the possible effects of successive repair procedures on the microstructure of welded steel SAE 4130 by TIG welding process. Discussions and results were made about the metallographic analysis , non-metallic inclusions and microhardness tests , which were conducted on samples taken from the cradle engine component after the end of its life , a model airplane T-27 Tucano , made by EMBRAER and belonging were performed FAB . The choice of such component is due to the fact that this is critical to flight safety since it provides support for the aircraft engine . Thus regions of the weld metal , base metal and heat affected , with samples of the original weld bead , free of weld bead and also with four rework procedures for TIG welding zone were analyzed . It was found that after the fourth rework there is an increase in the amount of martensite , which may weaken the material with respect to resistance to fatigue. It was also found that the regions of the heat affected zone and weld metal have higher microhardness values when compared to those found in the base metal due to favoring the formation of ferritic and tempered martensite microstructures . Moreover, a welding process promotes a region with less non-metallic inclusions than metal base , which also explains the difference in the results obtained

Comparação de custo e viabilidade técnica de obras com parede de concreto em relação a obras de alvenaria estrutural

Are being released in the construction market in Brazil ventures called Super 6. These businesses sell the promise of delivery of the apartment in six months after the launch of the venture. To meet this deadline are being deployed the constructive method of concrete walls using aluminum shapes. This system basically consists of pouring slabs and walls once, i.e. building up the wall shapes and slab joints. On the walls are used cloth, with reinforcements in vain and corners of walls and on these screens are tied the electrical boxes and conduits. For each tower is used the so-called system of half way, i.e. the system so it is sufficient to mount the Middle deck. Using a concrete which can be deformed in the next day you can lift one deck every two days with ready electric and hydraulicsystem, without having to tow the wall doing only minor fixes in the imperfections after concrete. With this system won an incredible speed in the construction of the structure reducing in almost one-third the length of the work. This work aims to compare in terms of cost-benefit of masonry structural systems and this new concrete wall system called Super 6. For this comparison will be used as parameter values used for the achievement of the Enterprise Portal of Roses of constructor Tenda which is one of the first to use concrete wall system. This project basically consists of seven towers of six floors each and will be budgeted the cost of this project if it were held in structural masonry. From these data it will be possible to make a comparison about the actual beneficial to adopt this system

Investigação sobre deformação neotectônica no lineamento Guapiara, região de Ourinhos, Fartura-SP e Santo Antonio da Platina - PR

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo do efeito da classe de furação na resistência à fadiga em junta alumínio – fibra de carbono

This work performs a comparative study of fatigue life of riveted lap joints involving classes of drilling which adjustment is made with interference or clearance. For this study, representative specimens of this joints were manufactured with four rivets distributed in two rows. In this context, are presented the test matrix, the methodology employed in performing of the tests, the used mathematical modeling, and that methods that are the basis for the latter are described through the theoretical foundation. Next, are present the results obtained in fatigue tests and images of the region of failure of the specimens. Finally, are present some comments and conclusions related to the results obtained

Estudo em fadiga no aço API 5L X80 soldado pelo processo HF/ERW

The technological advancement in order to improve the methods of obtaining energy sources such as oil and natural gas is mainly motivated by the recent discovery of oil reserves. So, increasingly , there is a need for a thorough knowledge of the materials used in the manufacture of pipelines for transportation and exploration of oil and natural gas. The steels which follow the API standard (American Petroleum Institute), also known as high strenght low alloy (hsla), are used in the manufacture of these pipes, as they have, with their welded joints, mechanical properties to withstand the working conditions to which these ducts will be submitted . The objective of this study is to evaluate the fatigue behavior in microalloyed steel grade API 5L X80 welded by process HF / ERW . For this, axial fatigue tests to obtain S-N curve (stress vs. number of cycles ) were conducted. To complement the study, it was performed metallographic , fractographic , Vickers hardness tests and tensile tests to characterize the mechanical properties of the steel and check whether the values satisfy the specifications of the API 5L standard . From the fatigue tests , it was concluded that the surface finish influences directly on the fatigue life of the material

Modelagem e simulação do mecanismo biela manivela e análise estrutural de biela automotiva

Nowadays, the automotive industry is working to optimize the design of engines, in order to reduce the fuel consumption with acceptable efficiency ratio. This undergraduate thesis is aimed at perform a kinematic/dynamic analysis of a slider-crank mechanism that is part of a four stroke internal combustion engine, the same engine that was used in the analysis described by Montazersadhd and Fatemi (2007). Two algorithms were developed based on Kane’s method to calculate velocities and accelerations of the mechanism bodies, and provide the acting forces at connecting rod joints. A SimMechanics model was developed to simulate the engine, and monitoring the same parameters that were calculated with the algorithms. The results obtained with both approaches were satisfactory and showed good agreement with the values provided by Montazersadhd and Fatemi (2007). The obtained results showed that the axial component of the rod joint efforts was caused by the pressure exerted on the piston head,whereas the radial component was related with the action of inertia loads. Besides, this thesis presents a connecting rod assembly mesh that is going to be used for static and fatigue finite element analysis in the future