25 documents found, page 1 of 3
Mechanical Properties and Microstructural Characterization of Aged Nickel-based...
Silva, Cleiton Carvalho; Albuquerque, Victor Hugo Costa de; Miná, Émerson Mendonça; Moura, Elineudo Pinho de; Tavares, João Manuel R.S.The aim of this work was to evaluate the different phases formed during solidification and after thermal aging of the as-welded 625 nickel-based alloy, as well as the influence of microstructural changes on the mechanical properties. The experiments addressed aging temperatures of 650 and 950 C for 10, 100, and 200 hours. The samples were analyzed by electron microscopy, microanalysis, and X-ray diffraction in ...
Thermal aging effects on the microstructure of Nb-bearing nickel based superall...
Albuquerque, Victor Hugo Costa de; Silva, Cleiton Carvalho; Normando, Paulo Garcia; Moura, Elineudo Pinho de; Tavares, João Manuel R.S.Secondary phases such as Laves and carbides are formed during the final stages of solidification of the nickel based superalloy Inconel 625 coatings deposited during the gas tungsten arc welding (GTAW) cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the c00 and d phases. The aim of this work was to evaluate the different phases formed during t...
Automatic microstructural characterization and classification using artificial ...
Nunes, Thiago M.; Albuquerque, Victor Hugo Costa de; Papa, João Paulo; Silva, Cleiton C.; Normando, Paulo Garcia; Moura, Elineudo Pinho deSecondary phases such as Laves and carbides are formed during the final solidification stages of nickel based superalloy coatings deposited during the gas tungsten arc welding cold wire process. However, when aged at high temperatures, other phases can precipitate in the microstructure, like the c00 and d phases. This work presents a new application and evaluation of artificial intelligent techniques to classif...
Determination of carbon steel bar diameter by nondestructive magnetic testing
Diogenes, Aldecira Gadelha; Moura, Elineudo Pinho de; Machado, André da Silveira; Gonçalves, Lindberg LimaCarbon steel is an important component in reinforced concrete structures. These composite materials are susceptible to various degradation processes, especially the corrosion of steel bars. Since they play an important role in the stability of reinforced concrete structures, these structures require periodic inspections to verify their physical conditions. Therefore, a nondestructive testing technique is propos...
Performance analysis of metaheuristic optimization algorithms in estimating the...
Guedes, Kevin Santos; Andrade, Carla Freitas de; Rocha, Paulo Alexandre Costa; Mangueira, Rivanilso dos Santos; Moura, Elineudo Pinho deFor a better use of wind energy, the accurate selection of the wind speed distributions that best represents the regarding wind regime’s characteristics is essential. The Weibull distribution is the most common, but this model is not always the most suitable. Therefore, in order to obtain more reliable information, the evaluation of different distributions becomes necessary. Another crucial step is the estimati...
Unbalance evaluation of a scaled wind turbine under different rotational regime...
Melo Junior, Francisco Erivan de Abreu; Moura, Elineudo Pinho de; Rocha, Paulo Alexandre Costa; Andrade, Carla Freitas deThis work aims to propose a different approach to evaluate the operating conditions of a scaled wind turbine through vibration analysis. The turbine blades were built based on the NREL S809 profile and a 40-cm diameter, while the design blade tip speed ratio (l) is equal to 7. Masses weighing 0.5, 1.0, and 1.5 g were added to the tip of one or two blades in a varying sequence with the intent of simulating poten...
Welding defect classification from simulated ultrasonic signals
Murta, Raphaella Hermont Fonseca; Vieira, Flávison de Almada; Santos, Victor Oliveira; Moura, Elineudo Pinho deNondestructive testing is widely used to detect and to size up discontinuities embedded in a material. Among the several ultrasonic techniques, time of flight diffraction (TOFD) combines high speed inspection, high sizing reliability and low rate of incorrect results. However, the classification of defects through ultrasound signals acquired by the TOFD technique depends heavily on the knowledge and experience ...
Classification of imbalance levels in a scaled wind turbine through detrended f...
Moura, Elineudo Pinho de; Melo Junior, Francisco Erivan de Abreu; Damasceno, Filipe Francisco Rocha; Figueiredo, Luis Câmara CamposThis work proposes to identify different imbalance levels in a scaled wind turbine through vibration signals analysis. The experiment was designed in such a way that the acquired signals could be classified in different ways. A combination of detrended fluctuation analysis of acquired signals and different classifiers, supervised and unsupervised, was performed. The optimum number of groups suggested by k-means...
Avaliação da proporção de fases em juntas soldadas de tubulações de aço inoxidá...
Souza, Guttemberg Chagas de; Pardal, Juan Manuel; Tavares, Sérgio Souto Maior; Fonseca, Maria da Penha Cindra; Martins, Fonseca Jose Luiz FerreiraDuplex stainless steels are high strength and corrosion resistant alloys, whose properties are devoted to the fine microstructure composed by similar amounts of ferrite and austenite and also to the high concentrations of Cr, Mo and N in solid solution. Not for coincidence, duplex steels are extensively used in chemical and petrochemical industries. However, welding operations conditions can promote the unbalan...
Characterization of cast iron microstructure through fluctuation and fractal an...
Moura, Elineudo Pinho de; Normando, Paulo Garcia; Gonçalves, Lindberg Lima; Kruger, S.E.This work aims at evaluating the performance of pattern recognition methods in the identification of different microstructures presented by cast iron, namely, lamellar, vermicular and nodular microstructures, through the statistical fluctuation and fractal analyses of backscattered ultrasonic signals. The signals were obtained with a broad band ultrasonic probe with a central frequency of 5 MHz. The statistical...