Linear Magnetic Dipole of Finite Length and Magnetic Particle Testing

摘要

In this paper, the shallow cracks on workpiece surfaces are approximated by the linear magnetic dipoles of finite length. The analytic expression for the magnetic field strength yielded by a linear magnetic dipole of finite length is derived according to Coulomb's law of magnetism. A series of typical curves for the spatial distribution of this magnetic field strength are plotted through the digital calculation whereby the principle of magnetic particle testing for shallow cracks is explained.