Influence of local deformation on critical current of high temperature superconductor tape

In many applications, high temperature superconductor (HTS) tapes are placed on top of uneven surfaces. Because the electrical properties of HTS tapes are sensitive to mechanical loading, mechanical stress generated at such local imperfections can considerably decrease the critical current of a HTS tape. Then a method of predicting degradation of critical current from a numerical simulation would be helpful. We present the results of 3D mechanical finite element model analysis, using the software ANSYS for optimising the geometry of a round CORT (Conductor-On-Round-Tube) cable. In these simulations, the HTS tape is bent around a circular former of certain diameter with a surface imperfection. We used three parameters to characterize the imperfection geometry: diameter of the former, the height and the width of imperfection. In order to validate the mechanical simulation results, we performed in-situ measurement of critical current of HTS tape.