Structural Features of Twisted Stacked-Tape Cables With High Lorentz Loads Using Finite Element Analysis

Abstract

Structural support features for a twisted stacked-tape cable (TSTC) were evaluated through finite element analysis (FEA) to evaluate the mechanical performance of a TSTC surrounded with a rigid copper core and exposed to transverse compression. Annealing of the copper core can occur during the manufacturing process; so, the stress accumulation of the stack was studied as a function of yield strength of the copper, and the results suggested that a lower yield strength copper would result in higher stress accumulation in the tape stack. To ensure adequate support for the cable, two possible solutions were presented: increasing the core diameter or adding a stainless-steel jacket outside the core containing the stack of tapes. Both options resulted in similar reduction in the maximum stress of the tapes. The mechanical stability of a conductor can also be affected by the thickness of the tapes used in the cable. For the same cable dimensions, higher current densities can be obtained using thinner tapes, which however could jeopardize the mechanical integrity of the support. Different tape architectures, varying substrate, and copper stabilizer thicknesses were also studied. Results suggested that for the same amount of current carried by each tape, thinner tapes will experience higher stress. Finally, a full-scale twisted model was developed. A more complex and time-consuming twisted model provides results that are very similar to the simpler untwisted configuration used in this work, justifying its utilization.