Avaliação da tenacidade à fratura em juntas soldadas circunferenciais de tubulações de processo

This work aims to analyze the toughness of a welded joint in the presence of a crack through the analysis of maximum tension the material can withstand the presence of this type of defect, since a discontinuity is likely to occur in this type of joint and its detection and its design is simple, using non-destructive testing techniques. The study will be conducted through the CTOD test - Crack-Tip Opening Displacement, with type specimens SE (B) - Single Edge Bend taken from a weld in the L-C position in relation to the length (longitudinal axis) of a test tube. The main idea is to simulate the welding conditions for the manufacture of industrial pipes, made in boiler shops (pipe-shop) within petrochemical plants. These pipes are often subject to operation with flammable and toxic subjected to high pressures and temperatures, where one can break the line can cause irreparable damage to the plant, the environment and the health of surrounding communities. With this study we evaluate whether the weld metal has the same properties as fracture toughness of the base material. This study shows the importance of using a qualified welding procedure for performing quality welds while maintaining the properties of the fracture toughness of the base metal. It was found from the results of tests using a welding procedure described for carrying out welding ensures mechanical properties very close to the base metal, which in terms of design is great, since one can ensure that the weld will the same characteristics of the base metal specified for the assembly of the pipe

Análise de inconformidades em obras recentes

Due to the large number of pathologies in the civil constructions justified to highlight the reasons for problems encountered and subsequently the most appropriate way of implementing procedures for certain services performed in civil construction. The intention here is to explain each of the subjects studied, identify and distinguish the conditions presented in the post delivery of civil constructions from construction X, through research and company documents, and highlight steps of the executives of some services civilians highlighted in this work to minimize, or cancel, future maintenance. Studies will be conducted in a more narrow, focused more specifically in the most happening pathologies in the constructions and how to perform each service to prevent future problems with masonry (non-structural cracks and crevices), waterproofing, window frames and cladding. Thus, this study seeks to protect the building, using material technology and equipment, to allow an increase in the service time of the building,

Efeitos de uma partida sobre o pico de torque funcional e convencional nos músculos isquiotibiais e quadríceps de jogadores de futebol de salão com e sem desequilíbrio muscular

Introdução – Uma das causas mais prováveis de lesões esportivas está relacionada aos desequilíbrios musculares e a fadiga muscular, que é evidenciada no decorrer de um jogo de futebol, principalmente no final do jogo. Esta pode ser avaliada através da comparação da força de contração máxima antes e após o exercício. A fadiga produzida durante o jogo diminui a força muscular concêntrica e excêntrica de flexores e extensores do joelho podendo aumentar a incidência de lesões. Objetivo - Avaliar o efeito de uma partida sobre o pico de torque funcional e convencional nos músculos isquiotibiais e quadríceps de jogadores de futebol de salão com e sem desequilíbrio muscular. Método – Oito jogadores de futebol de salão do gênero masculino, com idade entre 18 e 24 anos, fizeram três visitas ao laboratório: 1ª foram realizadas a antropometria e adaptação aos equipamentos; 2ª teste máximo no dinamômetro isocinético para determinar a razão do pico de torque funcional e convencional nos músculos isquiotibiais e quadríceps; 3ª idem ao 2ª, após a partida de futebol de salão. Análise estatística – através das médias ± DP dos dados obtidos foi utilizado o teste t para amostras dependentes e o Mann Whitney para comparação do pico de torque antes e após a partida de futebol de salão e para comparação da relação flexor/extensor pré e pós- esforço, respectivamente. Em ambos os testes foram adotado um nível de significância de p < 0,05. Resultados - Não foram encontradas diferenças significantes entre os grupos de atletas com desequilíbrio muscular na perna dominante (GD) e grupo equilíbrio (GE) e para os extensores e flexores do GD e GE nas condições Con60. Através do Mann Whitney foram encontradas diferenças...(Resumo completo, clicar acesso eletrônico abaixo)

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

Implementação de um tuboexpansor na refinaria do Planalto Paulista – REPLAN com objetivo do aproveitamento da energia contida nos gases residuais do FCC – Fluid Catalytic Cracking na geração de energia elétrica

The steel type AISI 4130 (ultra-high strength steel) is an alloy of low carbon and its main alloying elements are chromium and molybdenum, which improves the toughness of the weld metal. It has numerous applications, especially where the need for high mechanical strength. It is widely used in equipment used by the aviation industry, such as cradle-tomotor, and this is the motivation for this study. Cots are of fundamental importance, because the engine supports and maintains balance in the fixed landing gear. This equipment is subjected to intense loading cycles, whose fractures caused by fatigue are constantly observed. Will be determined the effects caused by re-welding the structure of aeronautical equipment, and will also study the microstructure of the metal without welding. The studies will be done on materials used in aircraft, which was given to study. The results provide knowledge of microstructure to evaluate any type of fracture that maybe caused by fatigue. Fatigue is a major cause of aircraft accidents and incidents occurred, which makes the study of the microstructure of the metal, weld and re-solder the knowledge essential to the life of the material. The prevention and control of the process of fatigue in aircraft are critical, since the components are subjected to greater responsibility cyclic loading

Comportamento fractal de superfície da zona de estiramento em aço 300M temperado

Fracture surfaces are the fracture process marks, taht it is characterized by energy release guieded by failure mode. The fracture toughness express this energy em stress and strain terms in pre-cracked samples. The strectch zone is the characteristic region forms by the transition of fatigue fracture and final fracture and it width demonstrate the relation with failure energy release.The quantitative fractography is a broadly tool uses in failure surfaces characterization that it can point to a material’s aspect or a fracture process. The image processing works like an investigation tool, guinding a lot of studies in this area. In order to evaluate the characterization effectivity and it respectivity studies, it used 300M steel that it was thermal treated by an aeronautical process known and it characterized by tensile test and energy dispersive spectroscopy (EDS). The tensile test of this material, made by ASTM E8, allowed the head treatment effectivity confirmation, beyond of mechanics porperties determination. The EDS confirmed the material composition, beyond of base the discussion about fracture mechanism presence. The fracture toughness test has also made, that it works to obtain the fracture surfeaces studies below self-similarity and self-affinity approaches. In front of all the exposed it was possible to conclude that the fractal dimension works like a study parameter of fracture process, allowinf the relation of their values with changes in thickness, which interferes directly in material’s behaviour in fracture toughness approach

Alterações microestruturais decorrentes dos sucessivos reparos de solda TIG aplicados ao longo da vida útil de uma estrutura aeronáutica crítica à segurança de vôo

The steel type AISI 4130 (ultra-high strength steel) is an alloy of low carbon and its main alloying elements are chromium and molybdenum, which improves the toughness of the weld metal. It has numerous applications, especially where the need for high mechanical strength. It is widely used in equipment used by the aviation industry, such as cradle-tomotor, and this is the motivation for this study. Cots are of fundamental importance, because the engine supports and maintains balance in the fixed landing gear. This equipment is subjected to intense loading cycles, whose fractures caused by fatigue are constantly observed. Will be determined the effects caused by re-welding the structure of aeronautical equipment, and will also study the microstructure of the metal without welding. The studies will be done on materials used in aircraft, which was given to study. The results provide knowledge of microstructure to evaluate any type of fracture that maybe caused by fatigue. Fatigue is a major cause of aircraft accidents and incidents occurred, which makes the study of the microstructure of the metal, weld and re-solder the knowledge essential to the life of the material. The prevention and control of the process of fatigue in aircraft are critical, since the components are subjected to greater responsibility cyclic loading

Projeto mecânico do sistema de transmissão de um veículo Baja

This study aims to determine the best configuration for the new gearbox of the new Baja´s vehicle from Piratas do Vale team, focusing on the gear train, in order to achieve high performance of it. To this end, first some information about the vehicle is gathered to determine the best pair of gears configuration, then calculations about maximum bending stress, fatigue and surface thereof are performed; ; thereafter static simulations are performed using an a appropriated software. Thus this paper shows a satisfactory design of the addressed, besides providing the Baja SAE team consultation material for future use in the project

Análise de variáveis eletromiográficas e cinemáticas em protocolo incremental de corrida na esteira

Muscle fatigue is described as a cause of injuries among the many related to the running practice. Therefore, the purpose of this study was to analyze the behavior of the amplitude (RMS) and median frequency (MF) of EMG signal of the iliocostalis (CI), rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM) biceps femoris (long head) (BFCL), tibialis anterior (TA) and gastrocnemius (lateral) (LNG) from the right lower limb, and the behavior of the parameters of amplitude (AP) and frequency (PF) spent in different percentages of the maximum speed during incremental protocol of treadmill running. 10 volunteers participated in this study, athletes, male, aged between 18 and 30 years with no history of injury in lower limbs and similar anthropometry. The protocol consisted of a treadmill test with initial velocity of 10 km.h-¹ and increments of 1 km.h-¹ each three minutes until volitional exhaustion, without rest interval. Synchronized collections were made of electromyographic and kinematic data. The signals were obtained through an acquisition module of biological signals (Telemyo 900 - Noraxon - USA) and software (Myoresearch - Noraxon - USA) calibrated with a sampling frequency of 1000 Hz, gain 2000 times. The raw data were filtered with a 60Hz notch filter, high pass and low pass 20Hz to 500Hz. To capture the image was used a digital video recorder (model NV-GS320, PANASONIC brand), and for image scanning and kinematic data collection was used the software Peak Motus 9.0 (ViconPeak). To obtain the values of RMS and FM analyzed the last ten passes of each speed through a specific routine (Matlab). To obtain these variables AP (m) and FP (stride I min) were analyzed for the last ten past each speed, using specific software (Peak Motus 9.0). After verification of data normality (Shapiro-Wilk) and homogeneity of the data (Levene), the comparison ...(Complete abstract click electronic access below)

Efeito da idade e de diferentes intensidades sobre o desempenho muscular de membros superiores e inferiores em mulheres

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Validação dos parâmetros aeróbio e anaeróbio a partir de protocolo não invasivo aplicado ao exercício resistido - supino reto

The purpose of this study was to investigate the validity of critical force test from maximal lactate steady state (MLSS) during resistance test using straight bench press. Five healthy male volunteers aged (22.6 ± 2.88 years), weight (76.3 ± 11.49 kg) e height (182.6 ± 7.54cm), trained in resistance exercise, and performed four diferent test to determine: one maximal effort (1RM), critical force using the critical power model (force vs 1/time limit - 20, 25 and 30% 1RM). The CF was the linear coefficient and the anaerobic impulse capacity (CIA) was the angular. MLSS was determined using loads of 80, 90, 100 and 110% of critical force. Blood lactate samples were abtained at each 300sec between each stage of total 1200sec. Maximal 30s test (M30) was accomplished with load of 25% of body weight in SBP. The results showed that the 1 RM was 79.4 Kgf (± 16.98), CF 10.1N (± 2.25), CIA 1756.82 N.s (± 546.96) and the R² 0.984 (± 0,02). The MLSS occurs at 100% CF load. The lactate concentration at the MLSS was 2.2 mmol/L (± 0.77). Significant correlation was observed between MLSS and CF on SBP (r = 0.88 p = 0.05). In M30 the minimum, mean and peak power were (25.0 ± 4.9, 28.0 ± 4.9, and 30.0 ± 4.6 kgf.rps, respectively). The fatigue index was 18.0% (± 6,8). The M30 was significantly correlated with Ppeak and Pmean (r = 0.98 for both, p = 0.003). The CF means has been validated to predict the resistance training and the CIA show to be a representative anaerobic parameter in straight bench press.

Manejo pré-abate de bovinos

The pre-slaughter moment begins with the animal´s loading on the farm and ends up in its drain. It is a period in which the animal is under physical stress caused by hunger, thirst, fatigue, injuries, and extremes of temperature and psychological stress, due to restraint, handling, innovation and fear. Stress and inappropriate handling bring bad consequences for the final product´s quality, requiring better handling conditions, facilities and equipment. Examples of consequences of mishandling: meat with abnormal color, DFD meat (dark, firm and dry), reduced product´s shelf life, bruises and broken bones in carcasses. The operators should be trained and oriented on the basic principles of biology, behavior and management of cattle. At every step of the pre-slaughter moment, the animals should be handled calmly and quietly to avoid excitement and stress. Operators should avoid shouting, whistling or any noise since cattle have very sensitive ears and can become stressed. If the animals refuse to move, the cause of the problem should be determined

Validação de uma escala colorida de esforço percebido para adultas jovens e idosas em caminhada na esteira

The perceived exertion has been used for the intensity control and exercise prescription. Among the various scales that estimate the perceived exertion, the Borg’s RPE scale is one of the best known. However, for populations with low levels of schooling or with visual difficulties such as the elderly, the application of these scales becomes more difficult. In previous studies, a color scale of perceived exertion was developed to aim for assistance in application of the scale and interpretation of perceived exertion. This scale showed high correlation with the Borg’s scale and proved to be valid to estimate the perceived exertion. Thereby, the aim of this study was to assess the validity of the color scale of perceived exertion to measure the perceived exertion in adult women of different ages. Participated in the study 12 young adult women with age of 21,7 ± 1,5 years old, and 10 elderly women with age of 60,3 ± 3,5 years old. The participants were submitted to an incremental exercise of treadmill walking with stages of 2 minutes duration. The inicial load was 5,5 km/h and inclination of 6% for young women and 2% for elderly women, both with 2% increments at each stage completed, without changing the speed. Heart rate and oxygen comsuption responses were determined at the 30 finals seconds of each stage. At the 60 finals seconds of each stage participants indicated the perceived exertion for the overall body, for the legs and for the chest, primarily in the color scale and following in the tradicional Borg’s scale. The analysis of variance for repeated measures was used to assess the effect of different loads on the perceived exertion and physiological responses. The correlations betwen physiological variables, color scale and Borg’s scale were analyzed in group and individually. In all analysis the significance...(Complete abstract click electronic access below)

Efeitos do exercício aeróbio prévio sobre a taxa de desenvolvimento de força em indivíduos ativos

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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