3-D nonlinear eddy-current analysis of alternating magnetic flux leakage testing - analysis of one crack and two cracks

The alternating magnetic flux leakage testing has been applied in the nondestructive inspection process for detecting cracks on the surface of steel. This paper describes numerical analysis using three-dimensional (3-D) edge-based hexahedral finite element method for this testing. The necessity of nonlinear analysis is clarified in comparison with the linear analysis (j/spl omega/ method). The characteristic of leakage flux is confirmed by verification experiment. The possibility of distinguishing two cracks is examined by calculating the detailed distribution of leakage flux around cracks.