Analytical Investigation of Axial Strain of the YBCO Tape on CORC Winding Cables Under Twisting Deformation

The conductor on round core cables (CORC) cable wound from superconductor YBa ₂ Cu ₃ O _7-x (YBCO) tapes is widely used in interposer magnets and power cable systems. It is well known that the current carrying capacity (specifically described by the critical current) of this superconducting tape strongly depends on its deformation. During the winding of CORC cables through YBCO tapes and then fitting magnets through CORC cables, accurately calculating the real axial strain of YBCO tapes resulting from the macroscopic deformation of CORC cables, especially twist deformation, is a crucial task. In this article, for a single layer CORC cable, we presented an analytic model that can calculate the axial strain of YBCO tapes when CORC cables suffer twisting deformation under external loads, and on the verification of this analytic model, we further predicted the relation between the critical current of the CORC cable and this twisting deformation. Calculated results show that the total strain of the YBCO layer increases linearly with the twisting angle of the CORC cable, and meanwhile, this varying relation is closely related to the key parameters of the thicknesses of the substrate layer of YBCO tapes, the winding angle, and core diameter of CORC cables. The analytic model and further predictions are significant for CORC winding and related magnet engineering.