A Stable FEM-BEM Hybrid Method for the Numerical Simulation of Magnetomechanical Coupled Problem with Both Inductive and Conductive Current Excitations Aiming to Application to Tokamak In-Vessel Structures

The in-vessel structures of tokamak devices sustain large electromagnetic force due to both induced eddy current and halo current. The coupling effect between the electromagnetic field and the mechanical vibration of the structures has a significant influence on the structural dynamic response. To assess the coupled mechanical behavior of in-vessel structures, a numerical method was proposed in this article based on the hybrid finite-element method and boundary-element method. The plasma current and halo current were modeled as a series of current filaments and a pair of current source-sink, respectively. To deal with the nonlinearity due to the coupling term of the magnetic flux density and the velocity, the block Gauss-Seidel iterative algorithm was adopted in the numerical method. The proposed numerical method was first validated against the experimental data of the TEAM 16 benchmark problem and then applied to the dynamic analysis of a simplified halo current problem of typical tokamak structures. The numerical method was proved both effective and numerically stable for the analysis of magnetomechanical coupled problem based on the reasonable simulation results.