INCREASING THE SIGNAL-TO-NOISE RATIO IN EDDY CURRENT NDT BY CREATING OF AN INHOMOGENEOUS ELECTROMAGNETIC FIELD

In this article, using the example of multistrand rope inspection, the ways of increasing the signal-to-noise ratio in eddy current control are considered. Based on the results of numerical simulation, a comparative analysis of encircling addycurrent probes with different lengths of the exciting coil is carried out. A probe with a narrow exciting coil has a pronounced dependence of the ratio of signals from defects in different layers on the position of the measuring coils. The use of measuring coils located at different distances from the center of the exciting coil makes it possible to increase the signal-to-noise ratio due to the separation in the radial direction of the parts of the object that mainly form signals and noise in different measuring coils. The use of a system of surface measuring coils instead of encircling measuring coils makes it possible to increase the signal-to-noise ratio due to the separation in the azimuthal direction of the parts of the object that mainly form signals and noise in each of the surface measuring coils.