Simple approximation of frequency characteristics and transition characteristics of ferromagnetic rods (linear model)

The data on the magnetic permeabilities and transition characteristics of ferromagnetic bodies (rods) are of certain interest for theory and practice of the eddy-current nondestructive testing. Despite the obvious simplicity of the physical processes of remagnetization of tested objects in the form of rods, sticks, pipes, plates, etc. in variable magnetic fields, the calculation of these characteristics using the well-known formulas is not always simple and convenient, for practice even within the framework of the linear model (*m = const). In the present study, a simple and fairly exact approximation which makes it possible to simplify the necessary calculations and clarify the results is proposed and considered. The paper describes a simple and fairly exact approximation which makes it possible, significantly to simplify calculations of both frequency and transition characteristics of ferromagnetic rods from an electrically conducting material with various cross-sections.