Impact of Anticlastic Deformation on REBCO Tapes Wound in Multilayer Round Cable

The aim of this work was to study the effect of anticlastic deformation on the coated conductor (CC) tape wound in multilayer round cable. As the edges of the CC tapes tend to lift after bending (effect of anticlastic deformation), in multilayer round cable with tapes in opposite directions, this causes local contact stress between the layers and consequently crossover kinking of the outer tape. The impact of tape kinking was investigated as a comparison between critical currents (I_c) measured on the tapes wound in a single-layer (not affected by kinking) and outer tapes wound in double-layer configuration (affected by crossover kinking) at the same winding parameters. The investigation was performed on the tapes wound by using tensioning force of 3 N, lay angle of 45° and tube diameters of 8 mm and 6 mm. The results showed that I_c of the tape affected by kinking is approx. 19% lower at tube diameter of 6 mm and 15% lower at tube diameter of 8 mm compared to tape not affected by kinking. The SEM analysis showed delamination of the REBCO layer in the place of contact stress that was obviously responsible for I_c degradation of the outer tapes in double-layer configuration.