A coupled electromagnetic-mechanical model for high temperature superconducting coils based on circuit model

The electromagnetic-mechanical coupling effect in second-generation high-temperature superconducting tapes (based on the rare-earth barium copper oxide (REBCO) materials) has attracted considerable research interest. In this study, an electromagnetic-mechanical coupled numerical model based on the circuit model is proposed, which captures the effects of mechanical deformation on coil inductance and critical current. Furthermore, an artificial neural network is introduced to rapidly compute inductance-related integrals, and the split-field iteration method is employed to achieve bidirectional coupling between the electromagnetic and mechanical fields. Based on the above model, the influence of electromagnetic-mechanical coupling on the multiphysics response of no-insulation (NI) coils is systematically analyzed. The results show that the coupling effect intensifies radial current flow during charging and reduces shielding current penetration. In terms of mechanical response, the coupling effect suppresses the maximum hoop strain from 0.457 % to 0.35 % during the early excitation stage, while exacerbates the strain from 0.456 % to 0.481 % after the system stabilizes. The coupled model predicts higher local peaks of azimuthal magnetization loss power density and increased radial Joule heating loss. Therefore, the coupled model can provide a more accurate assessment on the multiphysics behavior of NI coils and enhances the safety of magnet design.