Leszek Dziczkowski

TL;DR: The method of determining the equivalent parameters of the coil, a scaling method for a conductivity meter based on the elimination of liftoff on conductivity results, and a proposition for an effective method to measure the conductivity of rough elements are described.

TL;DR: In this article, an axially symmetric E-cored coil with a circular air gap inside the core column located above a two-layered conductive half-space is presented.

TL;DR: In this article, an axially symmetric mathematical model of an I-cored coil placed over a two-layered conductive material with a cylindrical surface hole was presented.

Abstract: Probes used in eddy current testing contain ferrite cores of various shapes. In this paper, an axially symmetric mathematical model of an I-cored coil with an air gap was shown. The coil was placed above a two-layered conductive half-space and the solution domain was truncated radially. Using the truncated region eigenfunction expansion method, expressions describing the magnetic vector potential and the impedance of such a coil were derived. The calculations were carried out in MATLAB, both for an air-cored coil and the I-cored one containing an air gap. The results were verified using the COMSOL Multiphysics package in which the finite-element method is applied and the values show a very good agreement. Moreover, impedance components for the I-cored coil with and without an air gap were compared. The difference between the two types was significant, particularly for low-frequency values.

TL;DR: In this paper, a mathematical model of a contact coil located above a conductive non-ferromagnetic plate is proposed to determine the sensitivity of the measured parameters of the eddy currents.