Fracture behaviors induced by electromagnetic force in a long cylindrical superconductor

Abstract

In the present work, the crack problem of a long cylindrical superconductor with a center crack is investigated. The Bean and Kim model of critical state are considered, and the stress intensity factors are calculated for zero-field cooling (ZFC) and field cooling (FC) magnetization processes, respectively. Based on the finite element method, the variation laws of the stress intensity factors for different magnetic field are obtained first. As the applied field decreases, the stress intensity factors increase quickly first, and then decrease gradually after they reach a peak value. Subsequently, for every length of the crack, the maximum of the stress intensity factor is calculated. Numerical results obtained show that, the FC activation process has more significant influence on the stress intensity factors than the ZFC activation process. Finally, the results obtained from Bean model and Kim model are compared. When the dimensionless parameter p is lesser, the results in two different critical state models are equal almost. Generally speaking, all of the results are useful for understanding the critical state model and the fracture mechanism of high-temperature superconductors.