Treinamento de força unilateral: efeitos sobre a taxa de desenvolvimento de força do membro contralateral

The aim of this study was to analyze the effects of unilateral isokinetic strength training at high speed (180°.s-1) of the dominant leg on the rate of force development (RFD) of the contralateral limb. The study included 18 male individuals, apparently healthy, with an average of 23 years, and without regular practice of physical activities. The subjects were divided randomly into two groups: control group (GC) and isokinetic group (GISOC). Assessments were made of the values of peak isometric torque (PT isom) and RFD of both lower limbs in the pre-training. So, the GISOC underwent an isokinetic strength training with high speed (180°.s-1) for 6 weeks, with the dominant leg only and then reassessed. It was found that there was no significant improvement in value of PT isom (p> 0.05), and the RFD for the dominant limb had a significant improvement (p< 0.05) compared to the pre-training and that there was no transfer of values to the contralateral side (p> 0.05). It can be concluded that the isokinetic training at high speed was not enough for significant cross education

Estudo da deformação heterogênea no ensaio do anel de atrito

The plastic deformation is widely used in the metallurgical market due to its positive factors such as low prices and high speed production. Forming process products are obtained in high quality, both surface quality and mechanical properties. Friction is an importante factor in metal forming. Friction study in metal forming can be accomplished indirectly, such as the ring test of friction. Two samples of different materials being mild steel and copper alloy were used. The results showed the influence of friction in the flow behavior of the deformation of the second phase, as evidenced by standard metallography. It is observed that in the outer regions of the ring, plastic deformation occured in the radial direction. In the central region of the disc deformation occured in the direction of compression and the inner region of the ring flux lines showed a significant deformation in the radial direction towards the center of the ring

Melhoria da qualidade de um processo de usinagem utilizando as técnicas de avaliação de Taguchi

Delivering to the customers a product or service with the expected quality associated to the huge competitiveness that exists in the market nowadays, has been making organizations increasingly focus on quality planning using techniques which are directed towards the continuous improvement process and production optimization. Thus, this paper aims to improve a machining process using the techniques of experimental design to the optimization and this also includes the analysis of the measurement system. For this purpose, the alloy Nimonic 80A, a nickel base superalloy, was used in the process due to its widespread use for high temperatures, applying this study the robust method proposed by Genichi Taguchi, determining the influence of the factors considered input variables, cutting speed, feed rate, depth of cut, type of tool, lubrication, and material hardness, in the output or response variable, surface roughness, concluding with the use of Taguchi orthogonal array L16 and by analysis of ANOVA that the factor feed rate is significant and offers greater effect on the response variable studied, should be set to 0,12mm/rev. Moreover, the factor type of tool has more influence on the process when compared to other factors, being CP250 the one more suitable to the process. Lastly, the interaction feed rate x cutting speed provides greater significance in the process regarding to surface roughness variable, being the best match between them 0,12mm/rev to the feed rate and 90m/min to the cutting speed. In order to evaluate the measurement system, it was applied the repeatability and reproducibility method (R&R), through which we saw that the system needs improvement (R & R = 88.04% >>> 30%) as the value found in the study was well above compared to the one that classifies the system as inappropriate

Usinagem da liga de níquel inconel 718 com pastilhas de cerâmica

The machining of super alloys resistant to high temperatures such as nickel alloys, inconel 718 specifically, is a very difficult job to obtain improvements in the process, due to the difficulty of machining at high cutting speeds, the use of these alloys in industries showed great developments in recent years, its application in aeronautical industry spread being used in vane turbo, compressor parts, props and set elements. The automotive, chemical, medical and others also took advantage of the great features of inconel 718 and has used the material. The high temperature resistant alloys have high machining difficulty, a fact that is associated with high cutting forces generated during machining which result in high temperatures. High levels of temperatures can cause deterioration of the cutting edge, with subsequent deformation or breakage, wear most common obtained in machining such materials are flank wear the formation of built-up edge for cutting and notch wear. The experimental part of the work consists in machining of nickel-based alloy Inconel 718 heat treated for hardness, using a tool based ceramic silicon nitride Sandvik (Si3N4) in order to compare the best results obtained in the master's thesis of SANTOS (2010) who used a tool ceramics also the basis of silicon nitride which was developed in the doctoral thesis of SOUZA (2005). Assays were performed on a CNC lathe and was noted for each cutting edge results obtained. Tests were made starting from an initial condition of the tool with cutting speed of 200 m/min, feed 0.5 mm and 0.5 mm depth of cut was reduced cutting speed for the subsequent tests with the same conditions of feed and depth of cut. The tool presented wear instant under two 200 m/min and 100 m/min, premature rupture of 50 m/min and finally cut provided with difficulty... (Complete abstract click electronic access below)

Otimização do processo de usinagem da superliga nimonic 80A utilizando o Método de Taguchi

Atualmente, atender as necessidades dos consumidores é uma das metas mais importantes, os consumidores estão em busca de produtos com qualidade e preços mais acessíveis, para isso, é indispensável que as empresas se atualizem para melhorar seus produtos e serviços. Com este cenário, as superligas estão cada vez mais ganhando mercado, pois possuem ótimas propriedades, principalmente em relação a operar em temperaturas elevadas, podendo proporcionar maior eficiência para motores que necessitam trabalhar em altas temperaturas. Em contra partida a essa vantagem, as superligas possuem uma baixa usinabilidade, sendo importante a análise do processo de usinagem para se tornarem mais aplicáveis. Este trabalho visa à otimização do processo de torneamento cilíndrico da superliga Nimonic 80A, com o intuito de melhorar a qualidade do produto, utilizando o Método de Taguchi, com o arranjo ortogonal L16, sendo o comprimento de corte definido como variável resposta e analisados seis fatores que poderiam influenciar na sua variação, tais fatores são: velocidade de corte, avanço, profundidade de corte, tipo de pastilha, lubrificação e dureza do material. Os resultados obtidos demonstraram que os fatores avanço, tipo de pastilha e lubrificação são significativos e exercem influencia no processo, sendo que o avanço deve ser ajustado no nível de 0,12 mm/rev, a pastilha a ser utilizada deve ser CP250 e a lubrificação deve ser feita de maneira abundante, para a otimização do processo. Com a análise dos resultados, também podemos observar a eficiência e confiabilidade do método utilizado, mostrando resultados coerentes

Efeitos dos parâmetros de usinagem no acabamento superficial de materiais cerâmicos a verde

Pós-graduação em Engenharia Mecânica - FEB

Analise comparativa do desempenho de ferramentas no torneamento do aluminio 2024

The aluminium alloys are used in many fields because of their versatility combined with the excellent aluminium’s properties, mentioned in the study. This study aims to compare the performance of polished Hard Metal, Hard Metal covered with TiB2 and High Speed Steel (HSS) tools, at the aluminium 2024 alloy’s turning, as a function of variation of some turning parameters such as: feed, depth of cut and cutting speed; and study the surface finish and the required power during turning by processing the output data, like analyze the chip’s features for each used tool. The results provide information of the tool’s material effects, when submitted to different turning conditions, about the output variable in question. In this way, it was possible to notice that although the Hard Metal covered with TiB2 tool has provided the better surface finish, the chip’s features were better when the turning was accomplished by the Polished Hard Metal tool. In relation to the required turning’s power, the lowest consumption occurred with the High Speed Steel tool

Usinabilidade e integridade superficial de implantes dentários

Pós-graduação em Engenharia Mecânica - FEIS

Dinâmica não linear e projeto de controle em sistemas de transporte vertical: comportamentos periódicos e caóticos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Engine LES with fuel-spray modeling

Pós-graduação em Engenharia Mecânica - FEG

Contribuição ao estudo do desgaste de bedames na usinagem de ligas de alumínio-silício

Pós-graduação em Engenharia Mecânica - FEIS

Caracterização do aço inoxidável ASTM A743 CA6NM e do seu revestimento de WC-10Co-4Cr aspergido termicamente por HVOF

Pós-graduação em Engenharia Mecânica - FEG

Utilização de turfa para remoção de metais potencialmente tóxicos de uma empresa recicladora de plásticos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo da aplicação de mínima quantidade de fluido no fresamento de acabamento da liga Ti-6Al-4V

Pós-graduação em Engenharia Mecânica - FEG

Análise comparativa do uso de ferramentas de metal duro sem revestimento e revestidas com diboreto de titânio na usinagem da madeira

Pós-graduação em Engenharia Mecânica - FEB