Three-dimensional finite element analysis of residual magnetic field for ferromagnets under early damage

• Three-dimensional (3D) finite element analysis is presented by calculating the residual magnetic field signals of ferromagnets under the plastic deformation.
• The contour maps of gradients of the tangential and normal residual magnetic fields are given, and the 3D effect is discussed.
• The present study suggests an effective defect identification method with metal magnetic memory technique.

In this study, 3D finite element analysis is presented by calculating the residual magnetic field signals of ferromagnets under the plastic deformation. The contour maps of tangential and normal RMF gradients are given, and the 3D effect is discussed. The results show that the tangential peak–peak amplitude and normal peak–vale amplitude are remarkably different in 2D and 3D simulations, but the tangential peak–peak width and normal peak–vale width are similar. Moreover, some key points are capable of capturing the plastic-zone shape, especially when the lift-off is small enough. The present study suggests an effective defect identification method with Metal magnetic memory (MMM) technique.