Experimental Study on the Impact of Double Bending at Room Temperature on the Performance of YBCO Coated Conductors

The performance of High Temperature Superconducting (HTS) tapes is strongly affected by the mechanical loadings they experience during manufacturing, cooldown and operation. Therefore, the development of HTS-based applications requires thorough investigations on the impact of these loadings on the critical current. In this work, a measurement procedure is applied to determine the critical current of a (Re)BCO tape at 77 K, after double bending at room temperature around a cylindrical mandrel. In this procedure, the tape is cooled down to cryogenic temperature, and the critical current is first measured on the straight sample. After warming the tape up to room temperature, a double bending around a cylindrical mandrel is applied in two opposite directions and the critical current is measured at the following cooldown. This analysis is repeated for different mandrel diameters in order to identify to study the impact of the curvature radius on the performance degradation. The application of one single bending at room temperature is compared to the results of the double bending procedure. The influence on the performance degradation of applying a known force to the tape during the double bending at room temperature is also experimentally analyzed.