Fracture analysis of bulk superconductors under electromagnetic force

Bulk high-temperature superconductors exhibit priority magnetic properties compared to the conventional permanent magnets. Single-grain bulk GdBaCuO superconductors have significant application potential due to higher critical current density Jc and trapped fields. However, bulk superconductors are subject to larger Lorentz forces under high magnetic fields and their performance is limited by damage to the materials. In this paper, a finite element model based on the H-formulation is used to solve for the electromagnetic force in bulk GdBCO containing defects or inclusions under application of a pulsed field. Strong local electromagnetic force enhancement is observed at the crack tip. A bond-based peridynamic (PD) approach is proposed for analysis of the dynamic mechanical behavior and brittle damage of the sample. Crack initiation and propagation paths can be predicted using PD theory. PD is thus shown to be a suitable method for dynamic fracture problem analysis. As a further demonstration of the proposed model's capabilities, the bulk fracture process is simulated. The effect of voids, cross cracks and multiple inclusions are presented. Results show that mechanical stability can be enhanced by the presence of silver particles.