CORC Cables: Numerical Characterization of the Critical Current After Bending

To satisfy requirements of high operating current densities, compact layouts, and the possibility to reach magnetic field higher than 20
$\,\mathrm{T}$
, at temperatures from 4.2
$\,\mathrm{K}$
to 20
$\,\mathrm{K}$
, e.g., necessary for the development of next generation of colliders, the CORC
^®
cable concept is of particular interest. Based on ReBCO high temperature superconducting tapes wound around a copper former, it exploits round cross-section guaranteeing electrical and mechanical isotropy. However, these cables can degrade as a result of the winding process and operating conditions, as ReBCO tapes are strain-sensitive. This paper presents a 3D multi-physics numerical model for characterizing the critical current (
$I_{c}$
) of bended ReBCO CORC
^®
cables, based on a
T–A
formulation implemented in COMSOL Multiphysics
^®
coupled with a thermal model of a straight cable, already validated against experimental results. The tape is approximated as a thin shell, taking advantage of its high aspect ratio, and the
$I_{c}$
scaling for the tape accounts for the local strain. A pure geometrical strain evaluation on the tape surface allow to properly account for the punctual degradation of
$I_{c}$
, as an input for the multi-physics model. The assessment of the voltage-current curve for the bent conductor has been compared to experimental results.