Programa de Pós-Graduação em Engenharia Mecânica - PPGEM /ITEC

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2341

O Programa de Pós-Graduação em Engenharia Mecânica (PPGEM) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará(UFPA). Tem por objetivo formar recursos humanos qualificados, e incentivar a pesquisa e o aprofundamento dos estudos técnicos e científicos relacionados ao campo de atuação da Engenharia Mecânica com aplicação na realidade e necessidades da região amazônica.

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Agora exibindo 1 - 3 de 3

Acesso aberto (Open Access)
Análise da influência dos solutos Zr e Ti sobre as propriedades mecânica, elétrica e de termorresistência de uma liga Al-Cu-Fe-Si destinada a Tx e a Dx de energia elétrica
(Universidade Federal do Pará, 2012-01-10) MACHADO, Paulo Cordeiro; QUARESMA, José Maria do Vale; http://lattes.cnpq.br/7443111804471290
The global energy context presents a steady increase in electricity consumption in the last century, thus requiring the search for new materials for use in wire and cable conductors of electricity. From these demands for new materials, was developed an analysis of the influence of solute titanium and zirconium in the modification of important characteristics of the Al-Cu-Fe-Si alloy, destined to be the middle conductor of electricity, aiming to get properties resistant to heat. For this study, the alloys were obtained by direct casting in Ushaped metal ingots, from the Al-EC, standing at the base levels of 0.05 wt% Cu, [0.24 to 0.28] wt% Fe and 0.7 wt% Si, and then inserting the contents of 0.26 wt% Zr and 0.26 wt% Ti. The experiments were, divided in two steps, STEP A and STEP B , respectively. In order to characterize mechanical, electrical and structure of alloys. The specimens after cold rolling (in diameters of 2.7, 3.0, 3.8 and 4.0 mm) were analyzed without heat treatment (STT) and with heat treatment (CTT): 230 °C for one hour, according to the protocol COPEL (Companhia Paranaense de Energia Elétrica), 310 °C and 390 °C for one hour, to evaluate the heat resistance at higher temperatures, thermal stability and analyze the microstructures developed in these heat treatments (TT). It was found that Ti has more capacity to refine the grain compared to Zr, which has less refined grains, but with better physical properties are presented and heat resistant.
Acesso aberto (Open Access)
Análise de sistemas de controle de vibração em máquinas rotativas utilizando atuadores formados por ligas com memória de forma
(Universidade Federal do Pará, 2009-12-04) SILVA, José Adriano Brito da; MESQUITA, Alexandre Luiz Amarante; http://lattes.cnpq.br/3605920981600245
The application of shape memory alloys (SMA) has been showed as a promising alternative in the vibration control area mainly due to the shape memory and pseudoelastic phenomena which this alloys present. In addition, they show large recovery forces and damping capacity when compared to traditional materials. Despite a great number of papers dealing with SMA abilities applied to vibration control in structures, there are only a few reports about applications of SMA in rotordynamics. Hence, this work focuses basic aspects in the numerical application of SMA actuators for vibration control in rotating machines. In the first analysis of this work it is used a Jeffcott rotor with SMA sleeves placed into one of the bearings. It has been employed different sleeve thickness in the martensite and austenite states and the changes in terms of amplitude and frequency are compared. Furthermore, in the second analysis, two different rotating systems with two discs and SMA springs applied at one and both bearings are analyzed under different set-ups. The springs have been placed externally to bearings and the work temperature is set according to the requirement of vibration control. Moreover, it was used a computational code to represent the thermomechanical behavior of SMA springs as well as a numerical code based on Finite Element Method (FEM) to simulate the dynamic behavior of rotors. The results of the numerical analyses demonstrated the SMA are efficient in the vibration control of rotating systems due to accomplish great reductions in the displacement amplitudes, changes in the critical speeds, suppression of unwanted movements and control of precession orbit shape.
Acesso aberto (Open Access)
Implementação e análise do desempenho de técnicas de monitoramento através de medição de vibração e correlação com corrente estatórica
(Universidade Federal do Pará, 2010-06-16) JESUS, Keliene Maria Sousa de; SOEIRO, Newton Sure; http://lattes.cnpq.br/7303174583088137
The growing demand for electricity coupled with the great importance of this sector to the national economic system has led the government and private companies to invest in studies for improving the performance of the systems involved in this process, given the important gains that this initiative can produce. In this context, this work is a contribution to the study of the development of a methodology for diagnosis of defects to the machine number three hydro Hydropower Plant Coaracy Nunes, located in Amapa State. In many situations the methods of vibration analysis is used to detect the presence of faults in this type of machine, this work will also be used to analyze the current signals to provide similar indications. This work aims to present a methodology for fault diagnosis in electrical machines using the vibration signals and correlation with the analysis of the stator current. Throughout this work presents a review of techniques for monitoring and diagnosis of the condition of electrical machinery, through vibration tests correlated with the characteristics of the stator current. The result of the correlation of vibration measurement with the current measurement is based on a methodology implemented by a system of acquisition and data processing platform developed in LabView. The experimental results were obtained from mechanical defects (unbalance and mechanical defects on the slopes, and internal bearings) induced in an experimental device designed with the intention to represent a generation system. Finally, the vibration and current signals were analyzed and compared to verify that the defects that were detected by the conventional vibration altered the behavior of current signals. The good results of this study demonstrate the feasibility of future studies in this area.

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