[en] Single-grain GdBCO bulk superconductors have significant applications potential due to their ability to trap stable and large magnetic fields. The internal fracture of these bulk superconductors caused by Lorentz force and thermal load is a key issue in their practical applications. The aim of this work presented here is to investigate the mechanical behavior of the bulk superconductor during pulsed field magnetization. The H-formulation and heat transfer equation are used to obtain the electromagnetic force and thermal load in the bulk with and without defects. Numerical simulations show strong local enhancement of the electromagnetic load at the crack tips. Moreover, dynamic stress intensity factors at the crack tips are presented based on the two-dimensional state-based peridynamic theory. In addition, the crack propagation path is predicted. Finally, different dynamic crack problems are considered to discuss the influence of crack, void, inclusion, and hole on the mechanical stability of the bulk. Results show that defects increase the risk of damage of superconducting bulks. (paper)