Investigation on an Encircling Pulsed Eddy Current Probe Performance Using COMSOL Multiphysics®

S. Majidnia[1], R. Nilavalan[1], J. Rudlin[2]
[1]Brunel University, London, United Kingdom
[2]TWI ltd, Cambridge, United Kingdom
Published in 2013

Conventional eddy current techniques have been used to a great extent for detection of surface breaking defects in conductive materials. However, detection of sub-surface defects is limited due to the single frequency and skin effect phenomena. Pulsed Eddy Current (PEC) techniques overcome these limitations. This work involves modelling of an encircling coil around a steel pipe with and without insulation. A comparison between the simulation results and experimental results collected by GMR (Giant Magnetoresistance) sensors was also carried out. COMSOL Multiphysics® proved to be useful in visualization of diffusion of magnetic flux around the pipe and its interaction with the surrounding defect region, which led to development of an optimum probe design including selecting the appropriate magnetic field sensors and their locations around the driver coil.

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