Numerical analysis of delamination behavior in an impregnated HTS Roebel cable during cooling

Abstract

The delamination failures of REBCO tapes inside impregnated HTS Roebel cables during cooling have been observed in existing experiments. In this work, the finite element analysis (FEA) based on the cohesive zone model (CZM) is applied to simulate the delamination failure within impregnated Roebel cable during cooling from 300 K to 4.2 K. The modified three-dimensional (3D) Roebel geometric model is adopted. Simplified calculation strategies are developed to reduce the modeling complexity and computational cost. As a result, delamination characteristics observed in previous experiments can be captured based on the numerical simulation. Parametric analyses indicate that the mismatch in thermal expansion between impregnating materials and REBCO tapes has a more severe impact on the delamination than the edge pre-crack during cooling. Meanwhile, the various levels of delamination damage among REBCO tapes are observed, and the effects of delamination strength on the numerical results are discussed.