Finite differences software for the numeric analysis of a non-destructive electromagnetic testing system
In this paper, theoretical bases for the development of a software for electromagnetic effects simulation based on the approximation method of finite differences using Scilab are presented. A methodology for programming the algorithm is discussed and a simulation test is conducted in order to validate it, which consists of a coil with a ferromagnetic core. Finally, this software is used in studies related to magnetic flux leakage by a simulation of a system for the measurement of magnetic flux density in plates with different defects, which include both 2D and 3D and defects with orientation of 45 degrees.
PROCESSAMENTO E CARACTERIZAÇÃO DE NÚCLEO DE FERRO PURO OBTIDO POR METALURGIA DO PÓ PARA APLICAÇÃO COMO CAPTADOR EM ENERGY HARVESTING
Nos ultimos anos, o termo colheita de energia tem sido utilizado em uma grande classe de aplicacoes, cuja principal funcao e a recuperacao da energia disponivel a partir de fontes, por exemplo, mecânica, solar, termica, entre outras, que de outro modo seria desperdicada. O objetivo deste estudo e o desenvolvimento e caracterizacao de um nucleo de po de ferro obtido por moagem de alta energia, bem como a utilizacao desse nucleo como captador em um processo de colheita de energia por inducao no intuito de observar a sua capacidade de colher energia. O ferro foi caracterizado por difracao de raios X e microscopia eletronica de varredura e realizados testes de bancada para avaliar a quantidade de energia colhida do captador desenvolvido. A analise estrutural mostrou que o po obtido e monofasico, sem presenca de impurezas. As micrografias apresentam caracteristica homogenea, com pouca porosidade. As caracteristicas magneticas do material obtido o classificam como material ferromagnetico mole, devido ao estreito laco de histerese. No testes para captacao de energia, o nucleo apresentou resultados satisfatorios, pois foi capaz de fornecer um nivel maximo de potencia de 0.41mW quando submetido a uma corrente eletrica em seu enrolamento primario de 15 A
Traceability strategy for gear-pitch-measuring instruments: development and calibration of a multiball artifact
There is a strong demand to ensure the traceability of gear-measuring instruments (GMIs). We propose a multiball artifact (MBA) for the evaluation of pitch-measuring accuracy. The aim of the MBA is to transfer the minimum uncertainty from a calibrated value at the National Metrology Institute of Japan (NMIJ) to a measured value of GMIs at a shop floor. The MBA is composed of equally spaced high-accuracy balls around an axis. The pitch-measuring accuracy of GMIs is evaluated by measuring the angular pitch deviation of the balls instead of the angular pitch deviation of a gear. We calibrated the angular pitch deviation using a coordinate measuring instrument (CMM) at the NMIJ and adapting a multiple-orientation technique. We proposed a calibration strategy of the angular pitch deviation. The calibration value of the pitch deviation for the MBA at the NMIJ was obtained with a measurement uncertainty (U95) of 0.2 µm. We evaluated the pitch-measuring accuracy of a GMI using the calibrated MBA. Each value of U95 for the cumulative and single pitch deviations for the left and right flanks was less than or equal to 0.5 µm. The small uncertainty was transferred from the NMIJ to the GMI.