Trapped field analysis in an HTS bulk with a crack using 3D finite element method

The trapped field variation of a high temperature superconducting (HTS) bulk before and after a crack happens, which was impossible to simulate using 2D analysis method, was calculated in this paper. 3D finite element method (FEM) and iteration method were used to find screening current distribution inside an HTS bulk. In 3D analysis of an HTS bulk with a crack, calculated current distribution inside an HTS bulk should obey the equation of current continuity. For this purpose, ∇φ variable was set to satisfy the equation of current continuity, which was impossible to be considered directly by the FEM governing equation using critical state model. Also, boundary condition at the surface of an HTS bulk was applied to consider the equation of current continuity. Simulation results were compared with experimental ones to verify the validity of the suggested simulation method.