Compaction performance analysis of copper-sheath reinforced CORC cables

Abstract Compaction of a copper sheath is a key fabrication step for conductor on round core (CORC) cables in cable-in-conduit conductors (CICC) , as it directly affects both mechanical strength and superconducting performance. In this work, systematic compaction experiments were first conducted on 24-layer, 66-strand CORC cables under different prescribed inner diameters of the sheath. The measured critical currents reveal a clear degradation trend with increasing compaction severity, highlighting the necessity of quantitatively understanding the underlying damage mechanism. To interpret the experimentally observed degradation, a detailed mechanical finite element model of the compaction process was established to evaluate the stress and strain evolution in individual Yttrium Barium Copper Oxide (YBCO) tapes. The mechanical results were subsequently incorporated into an electromagnetic formulation through a strain-dependent critical current density model, forming a force–electromagnetic coupling framework. The predicted cable critical currents show good agreement with measurements across multiple compaction levels, confirming that the observed performance degradation primarily originates from tape damage accumulated during compaction. Based on the validated model, parametric analyses were further performed to investigate the influence of key process parameters. The prescribed inner diameter of the sheath is identified as the dominant factor governing performance retention, while sheath wall thickness, compaction velocity, and roller configuration exhibit secondary effects. The proposed framework provides quantitative guidance for optimizing compaction processes and supports the reliable mechanical–electromagnetic design of high-current-density CORC-CICC conductors.