A comparative study of 3D and axisymmetric magnetizer assemblies used in magnetic flux leakage inspection of pipelines

Axisymmetric numerical codes are often used in modeling non-destructive testing phenomena, to approximate geometries and defects which are not truly axisymmetric in nature. This is especially true in cases where large computational resources are needed to model the exact geometry. However, there has been no study to confirm the nature and extent of errors introduced by an axisymmetric approximation. The gas pipeline industry makes use of bath axisymmetric and non-axisymmetric magnetizers for the magnetic flux leakage inspection of pipelines. The authors utilize this platform to perform a comparative analysis of axisymmetric and non-axisymmetric magnetizers from a design perspective and also study the differences in respective electromagnetic behavior.