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

Abstract

In this study, we aimed to design a coil sensor prototype capable of detecting metallic area loss based on numerical simulations using the magnetic flux leakage (MFL) method. Unlike previous numerical simulation-based studies, which are only conducted to obtain the MFL itself, the main objectives of this study were (1) to acquire the induced current in the coil sensor and (2) to optimize the apparatus based on a time-dependent numerical analysis. As a result, the optimum values of parameters in magnetizing and sensing units were obtained numerically. A magnetic sensor prototype was then fabricated using the optimum parameters obtained by numerical parametric study. Finally, experimental validation tests were conducted on a solid steel rod specimen with a stepwise cross-sectional reduction flaw. It was observed that numerical simulation had approximately 91% precision compared to the experimental test. The results reveal that application of a realistic numerical simulation of an MFL coil sensor can probably provide essential information for MFL-sensor fabrication and allows for preventive measures to be taken before manufacturing failure or defect misdetection.

Development of an MFL Coil Sensor for Testing Pipes in Extreme Temperature Conditions

“…The scale of Alnico5 grade type 54 × 83 × 70 mm [ 43 ] was chosen because it has some excellent characteristics at different temperatures. Its maximum operating temperature is 500 °C, making it simple to monitor at higher temperatures.…”

“…Furthermore, since copper wires have lower number of turns, printing them on a small circuit board is much easier. As a result, a coil sensor with 200 turns of wire cannot only be easily printed and fitted onto a small circuit board, but it can also detect small cross-sectional losses with ease, and therefore a coil sensor with 200 turns of wire was considered [ 43 ].…”

“…The relationship between changes in voltage and varying pipe sample thickness is found to be linear. Magnetic sensors transform magnetic induction signals obtained into voltage signals, which are observed using an oscilloscope [ 43 ].…”

Research on the magnetic flux leakage field distribution characteristics of defect in low-frequency electromagnetic detection technique

“…It is clear that the use of the unsaturated AC excitation method in LFET [8,9,10,11] inevitably results in a weakened LF-MFL field at defects in the surface of inspected materials. An inductive magnetic coil [12,13,14,15,16] (LFET coil) is typically used as a substitute for traditional magnetic sensitive component [17,18] to avoid disturbances from the external DC magnetic field, reflecting the tangential magnetic variation. Meanwhile, the highsensitivity magnetoresistive (MR) sensor is always adopted as the signal acquisition medium [19,20,21], although it is affected greatly by spatial magnetic field.…”

Stray Flux Sensor Core Impact on the Condition Monitoring of Electrical Machines

“…In other industrial applications the development of new magnetic field sensors is an ongoing research field. The use of microwires [17], the delta-E effect [18] and the magnetic flux leakage sensor [19] are some of the recent novelties in the area.…”