A double cantilever beam model for fracture toughness analysis of superconductors

Due to their high current-carrying property, high-temperature superconductors such as multilayered superconducting cables have great potential applications in space solar power stations. The force induced by flux pinning may be very high and cause damage of superconductors. In this paper, the double cantilever beam (DCB) specimen for high-temperature superconductors is investigated and the energy release rate, mode I and mode II stress intensity factors are obtained in closed-form. For mode I crack, the energy release rate and stress intensity factor under magnetic field are found to be larger than those without magnetic field. However, mode II stress intensity factor is independent of applied magnetic field. In addition, mode I stress intensity factors with root effect are dependent of the ratio of length to thickness. This is contrary to the results without root part, which is independent of the ratio of length to thickness. The results are useful for determining fracture toughness of superconductor materials.