Model of a Surface Flaw and Calculation of Topography of Its Magnetic Field for Tangential Magnetization by Alternating Magnetic Fields. Quasi-Stationary Case

摘要

A model of a surface flaw is proposed. The model describes topography of the magnetic field for tangential magnetization by an alternating magnetic field H_(omega) at a frequency omega. It is shown that H_(omega) can be represented in the form of two multipliers: one describes the dependence on the (X, Z) coordinates and the flaw parameters (the depth h and the opening width 2b) and the other describes the dependence on the electrophysical properties of the tested material in which the surface flaw is located (the specific conductivity sigma and the relative magnetic permeability mu). The computational model proposed makes it possible to describe the magnetic field topography (omega = 0) reducing it to the quasi-stationary case and extend representations on the formation of magnetic fields induced by surface flaws with allowance of the magnetization frequency omega. The data on processing the experimental dependences in accordance with the proposed computational formulas give satisfactory results which confirm the validity of the computational model proposed in the study.