Analytical modeling of the transient response of a coil encircling a ferromagnetic conducting rod in pulsed eddy current testing

Transient response of a driver-pickup coil probe in transient eddy current testing

“…The common approach is to formulate time-harmonic solutions, which describe the electromagnetic fields in a system, in order to calculate the change in a coil's impedance as it interacts with a conducting structure [4][5][6][7][8]. In a less developed approach, transient eddy current models consider the voltage induced in a pickup circuit [9][10][11][12][13][14] given a prescribed current that has been applied to a driver coil. Under voltage control, changing material characteristics and inspection geometries will distort the resultant current signal through feedback effects.…”

Transient response of a driver coil in transient eddy current testing

“…The experimental and theoretical results are in excellent agreement. The longer time-scale, associated with the steel rod from stronger electromagnetic interactions arising between the coil and the sample due to magnetization [21] effects. The theory emerged, sets the stage for the consideration of an inductive system, which contains a driver coil, a pickup coil and a ferromagnetic conducting structure.…”

“…Exterior and interior solutions (5) and (8), respectively, are matched at the rod's boundary, at which r c = as shown in Figure 1, using the appropriate boundary conditions [21] (…”

“…However, the Fourier transform of a convolution is simply the product of the transforms [18]. Thus, by Fourier transforming (21) such…”

Damage detection of cracks in carbon fibre reinforced composites by pulsed eddy-current testing

“…The depth of penetration into the tested material is controlled by the conductivity of the material and also the work frequency. Transient eddy-current (TEC), also called pulsed eddy-current (PEC), is an emerging NDT technique that employs a pulsed excitation to induce a [3][4][5][6].…”