Crack Problem for Thin Superconducting Strip in a Perpendicular Magnetic Field

In this paper, we investigate fracture behavior for the superconducting strip with a central crack by means of the finite-element method. The crack is assumed to be small enough such that the perturbations of the crack on the shielding current and the magnetic field are negligible. The Bean model where j_c is field independent is adopted. We consider two cases, i.e., superconducting film with and without substrate. The stress intensity factors in the thin strip for the decreasing field are obtained. Compared with the case without substrate, the effect of the substrate on the stress intensity factor depends on the applied field B_a.