Numerical study on corrosion profile estimation of a corroded steel plate using eddy current

This article presents corrosion profile estimation as a method to determine the extent of corrosion in steel members having corroded exterior, with or without protective cover, when the only side accessible to the eddy current probe is highly uneven. A high frequency eddy current method is proposed to estimate the corrosion profile of a steel plate directly from the probe lift-offs regardless of varying plate thickness. The three-dimensional, numerical simulations were carried out in the FEM software, COMSOL Multiphysics 5.2a to verify the suitability of this method. A parametric study is conducted to determine the effect of coil height, diameter, their ratio and tilt angle of reflection probe on the estimation accuracy of a triangular notched profile, representative of corrosion, whereby a geometrically optimized probe is obtained. It is then employed to determine the corrosion profile of a corroded steel plate with and without protective cover. The estimated corrosion profiles show good agreement with the actual profile measured by laser displacement meter, confirming the sufficiency of proposed method.