Mechanical and transport characteristic exploration for coated conductors by hoop stress tests

The authors have explored mechanical and transport characteristics of coated conductors by hoop stress tests at 4.2 K, 11 T. Two monolayer coils, which were YBa₂Cu₃O₇ (YBCO) and GdBa ₂Cu₃O₇ (GdBCO) coils, and a double-stacked single-pancake coil were tested. The mechanical and electrical behavior of monolayer coils were simple, thus they were well explained by simple forms. The stress and strain were easily evaluated by using BJR relation and strain gauge measurements. On the other hand, the behavior of the pancake coil was not simple. The analytically evaluated azimuthal strain was qualitatively consistent with measured strain. However, the measured radial strain was not explained by analytically because of non-monolithic deformation of the coil. The transport characteristic was influenced by the non-monolithic deformation.