Speaker
Description
A new testing facility employing a 15-T transverse field to access the full-service-field characteristics of superconducting materials is now under development in China. A primary objective involves producing a large bore 15-T dipole magnet to serve as the source of the transverse magnetic field load. The magnet consists of a Low-Temperature Superconducting (LTS) dipole magnet providing 12 T and a High-Temperature Superconducting (HTS) dipole magnet insert providing 3 T. The HTS dipole magnet insert is composed of four coils wound with REBCO tapes, and a block-type configuration with flared ends is utilized to acquire high magnetic field within a large bore. Reliable prediction of strain and stress inside the coil is paramount for designing suitable support structure. In this paper, the stress and strain under high magnetic fields were analyzed using both homogenized and detailed models, with special emphasis on the mechanical properties of the flared ends. Firstly, the mechanics in superconducting coils are modeled assuming homogenized material properties inside a coil volume. Then, a multi-scale structural analysis model suitable for no insulated HTS coil was developed, the model takes into account the contact nonlinearity of the component structure, which can simulate the contact and separation behavior between adjacent turns during the deformation process. We discussed the mechanical properties of the magnet based on the analysis results, which show that significant stresses occur at the flared ends. Furthermore, considerable differences between the behavior of modeled homogenized coil blocks and coils where turns are individually considered. This work can effectively guide the structural design of the HTS dipole magnet insert.
