Characterization of Surface Breaking Cracks Using One Tangential Component of Magnetic Leakage Field

IEEE Transactions on Magnetics, Vol. 44, No.4, April 2008.
R.K. Amineh, N.K. Nikolova1, J.P. Reilly, and J.R. Hare

Abstract   An inversion procedure is proposed for full characterization of rectangular surface breaking cracks based on measurements of only one tangential component of the magnetic field in the magnetic flux leakage (MFL) technique. The parameters of interest include orientation, length and depth of the cracks. We assume that the length and the depth of the investigated cracks are much larger than the crack width such that the variation of the MFL response with respect to the width is negligible. The proposed procedure employs fast direct methods which provide reliable estimation of the crack parameters in three separate consecutive steps. De-noising and correction techniques are proposed as well. The accuracy of the proposed estimation methods is examined via simulations based on the finite element method (FEM) as well as experimental MFL data.