Analysis of Damage Behavior of REBCO Stacked Tapes Under Bending Loads

The rare-earth barium copper oxide (REBCO) coated conductor (CC) tape is a typical laminated composite material with broad application prospects. The presence of substrate and stabilizer layer significantly improves its mechanical performance. To meet the current-carrying capacity requirements of the magnet, a stacked tape structure is often employed. However, this structure negatively impacts mechanical performance, reducing bending and torsional strength. In this study, a three-dimensional (3D) stacked tapes bending model is developed, and the results of stress-strain calculations for each layer of the tape are simulated and verified. Subsequently, the distribution of stress of a single tape under bending was analyzed and the relationship between normalized damage area and critical current was obtained. Furthermore, the damage mechanism in stacked tapes was examined, revealing that REBCO layers far from the neutral plane are prone to damage due to extensive tensile and compressive strains, while those near the neutral plane suffer delamination due to shear stress. Finally, the I_c degradation prediction of stacked tapes was achieved, with a maximum relative error of 2.2%.