Vector-Based Eddy-Current Testing Method

Abstract

We present a type of eddy-current testing (ECT) method based on measuring the reaction of the Lorentz force by using a small permanent magnet (PM) as the probe. The means of measuring impedance is superseded by measuring force. By analyzing the variations in different components of the reaction of Lorentz force, the defects characteristics within the measured conductor can be revealed. The results indicate that the vector-based eddy-current testing method obtains good quantitative results and precisely evaluates the lift-off effect during measurement along two orthogonal directions. Numerical simulations are performed to provide supports for the experimental results. The method described in this paper may have great potential for use in industrial nondestructive testing applications.

Rectified Lorentz Force from Thermal Current Fluctuations

“…The corresponding eddy currents have applications at low frequencies for noninvasive material testing (e.g., reduced conductivity at cracks). Alongside currents induced by oscillating magnetic fields, the Lorentz force also plays a role in this context [1][2][3]. At frequencies from the infrared through the near-ultraviolet (UV), the Lorentz force is responsible for frequency mixing because it is a product of current and field.…”