Flux-Pinning-Induced Stress Behaviors in a Long Rectangular Superconducting Slab With a Central Rectangular Hole

In this paper, the rectangular hole problem is investigated for a long high-temperature superconducting slab under electromagnetic forces. The effects of rectangular hole on the magnetic flux density distribution in the slab are considered in either the Bean model or the Kim critical state model in the case of the descending field both for the zero-field cooling (ZFC) and the field cooling (FC) magnetization processes. Based on the finite element method, both the corresponding stress concentration factors near the corners and the distributions of nonzero principle stress along the hole edge are numerically calculated and discussed. Numerical results obtained show that the ZFC activation process has more significant influence on the stress concentration factors than the FC activation process. For every activation process, the peak values of stress concentration factors in the Bean model are larger than the corresponding ones in the Kim model. In addition, in the Kim model, the peak values of stress concentration factors generally decrease with the increasing of the introduced dimensionless parameter p. Additionally, the stress concentration factors usually increase with the increasing of the ratio of length and width of the hole. The present study should be helpful to the design and application of high-temperature superconductors.