Abstract：Nb3Sn superconducting composite strands have wide applications high magnetic field engineering, their tensile strength is a key parameter to assure and access the safety of long-time service. Using the Curtin-Zhou model which is on the basis of the Weibull/Poisson statistics as well as the shear lag theory, the fragmentation of filament in composite strands can be well described, and an analytical model is proposed to obtain the statistic tensile strength and the failure probability. The computation results indicate that when the initial damage parameter is rising, the statistic tensile strength is dropping sharply; at the service temperature 4.2 K, when Weibull modulus is equal to 8, the tensile strength decays from 900MPa to about 480MPa, which coincides well with the experimental results; as the initial damage parameter is near 1, the normalized variance reaches to its maximum value. For Nb3Sn superconducting composite strands, the filament initial damage and Weibull modulus both have strong influence on their statistic tensile strength and failure probability.
2018, Vol. 39 
