NON-DESTRUCTIVE DETERMINATION OF MAGNETIC PERMEABILITY TENSOR IN MATERIALS OF ARBITRARY SHAPE

摘要

A method of non-destructive determination of a local magnetic permeability tensor of a material comprises testing by X-ray diffraction on a first surface to identify and measure any surface stress in the material; performing a calibration test using magnetostriction to identify any effect of any determined stress; subjecting the material to a magnetic field having a strength H and measuring a field of induction B on the surface at the selected location and repeating this step by using gradual increases of H until a saturated value is determined for B, to determine a distribution of magnetic domains at the selected location; repeating the determinations of saturated values for B at additional locations on each selected surface of the material; and using the saturated values and distribution of magnetic domains to derive the magnetic permeability tensor. The non-destructive method provides increased accuracy for stressed or unstressed materials of arbitrary shape.