Sensitivity Analysis of a Magnetic Circuit for Non-Destructive Testing by the Magnetic Flux Leakage Technique

Abstract

Monitoring the integrity of structures in the oil and gas industry is a mandatory task to prevent both natural disasters and economical losses. This paper presents the optimization of the geometry of a magnetic circuit for the detection of defects in pipelines by the magnetic flux leakage method. The main goal is to perform a sensitivity analysis on the geometrical parameters of the circuit to find configurations that improve the performance of the defect searching tool. The sensitivity analysis of the design parameters of the magnetic circuit is based on numerical evaluations of the performance of the tool using the finite element method. The commercial finite elements software utilized for this analysis is COMSOL Multiphysics®. The results obtained in this investigation serve to identify the geometrical configurations that provide better performance, with respect to other configurations, for the detection of the same defect. Also, by using the analytical model of the magnetic flux leakage, the results obtained by means of the analytical model can be compared to the results from the finite elements model. The findings of this investigation can be utilized as guidelines for the design of magnetic circuits for non-destructive testing using the magnetic flux leakage technique.Key words: Magnetic flux leakage; Non-destructive testing; Magnetic circuit; Sensitivity analysis; Finite elements. RESUMENEl monitoreo de integridad estructural en la industria petrolera es una tarea muy importante para prevenir desastres tanto ambientales como económicos. Este artículo presenta la optimización de la geometría del circuito magnético para la detección de fallas en oleoductos por la técnica de fuga de flujo magnético. El objetivo principal es realizar un análisis de los parámetros geométricos del circuito para encontrar la configuración que incremente el desempeño del sistema para la detección de fallas. El análisis de la sensibilidad de los parámetros del circuito se basa en una evaluación numérica del desempeño del sistema usando el análisis por el método de los elementos finitos. El software comercial utilizado para este análisis fue COMSOL Multiphysics®. Los resultados obtenidos en esta investigación sirven para identificar la configuración geométrica adecuada para la mejora del desempeño del sistema, con respecto a otras configuraciones, para la detección de la misma falla. También haciendo uso del modelo matemático del fenómeno, se pretende comparar los resultados obtenidos por el modelo matemático y el modelo por elementos finitos. Los descubrimientos en esta investigación pueden ser usados como guías para el diseño de circuitos magnéticos para ensayos no destructivos por la técnica de fuga de flujo magnético.Palabras claves: Fuga de flujo magnético; Ensayos no destructivos; Circuito magnético; Análisis de sensibilidad; Elementos finitos.Cite this article as: C. Jaimes, S.Roa, "Sensitivity analysis of a magnetic circuit for non-destructive testing by the magnetic flux leakage technique

Design and Optimization of an MFL Coil Sensor Apparatus Based on Numerical Survey

“…To assess the integrity of structures, structural health monitoring (SHM) for metal members, such as pipelines in the oil and gas industry, load carrying cables in bridges, lifts, cranes, etc., is an essential task and must be done regularly to eliminate any chance of structural failure and economic loss [1]. For instance, the current transport system for oil–gas products is a pipeline which requires routine inspections due to the presence of humidity and underground pressure, because any metal losses, cracks, and corrosions may cause an accident.…”

“…However, in their numerical model, an actual sensor was not simulated and, more importantly, the parameters of the sensing unit were not optimized as well. To evaluate any changes in an MFL signal caused by the geometry of the magnetic circuit, Jaimes Saavedra et al [1] performed a preliminary parametric simulation based on the MFL method. They concluded that, by increasing the thickness and reducing the length of the yoke, greater density flux leakage will be acquired.…”