Development of a Simplified Numerical Model for the Design of 2G High-Temperature Superconductors

Within the past few years, robust superconductors known as second-generation high-temperature superconductor (HTS) tapes were developed for different industrial applications. For some of them, it is necessary to transform the flat shape of the tape into a cylindrical one. It requires special fabrication steps that include phases of large-scale bending, which induce both axial and shear stresses. It could lead to the degradation of the superconductive layer. The manufacturing process of an HTS cylindrical wire requires some analysis of stress and strain induced during fabrication. The selected process also defines the initial tape architecture. The use of the finite-element method for the analysis of the model of this complex material requires fine meshes and a lot of computation time because of the ultrathin size of the superconductive layer. In this paper, we present a simplified model, based on the classical beam theory, along with the subdivision of each layer into small sublayers affected by purely axial stress. The model is created with consideration of the plastic behavior of the HTS tape consisting of different materials. The model has been validated by its comparison with finite-element analyses on simplified cases. Then, it was used to improve the optimal design of the HTS tape on the basis of analysis of different wires used in industry. According to the analysis, some recommendations on the optimal architecture reducing the stresses in the superconductive layer, have been given.