Influence of Repeated Tensile Stress on Determining the Critical Tensile Stress/Strain of Copper Reinforced Bi-2223/Ag Tapes

Critical stress/strain is an important parameter to describe the transport property of superconductors under mechanical stress. The critical stress/strain of specified superconductor should be gotten before the superconductor is applied to manufacture devices. Determination of the critical stress/strain of specified superconductor is related to the chosen reduction percentage of the critical current under monotonic mechanical stress. However, in practical applications, superconductor also withstands repetitive mechanical stresses. Therefore, the influence of repetitive mechanical stress on the critical current or N value should be considered when the critical stress/strain of the superconductor is determined. Therefore, in this paper, the electrical transport property of copper reinforced Bi-2223/Ag tapes under both monotonic and repetitive tensile stress was studied theoretically and experimentally. Based on analysis of the change of critical current and N value under monotonic and different repetitive tensile stresses, the critical stress and strain of this superconductor tape were proposed.