Statistical analysis of the distribution of critical current and the correlation ofn value to the critical current of bent Bi2223 composite tape

Abstract

Distributions of local and overall critical currents and correlation ofn value to the critical current of bent Bi2223 composite tape were studied from thestatistical viewpoint. The data of the local and overall transport critical currents andn valuesof the Bi2223 composite tape specimens were collected experimentally for a wide range of bendingstrain (0–1.1%) by using the specimens, designed so as to characterize the local and overall critical currents andn values. The measured local and overall critical currents were analyzed with various types ofWeibull distribution function. Which of the Weibull distribution functions is suitable forthe description of the distribution of local and overall critical currents at eachbending strain, and also how much the Weibull parameter values characterizingthe distribution vary with bending strain, were revealed. Then we attempted toreproduce the overall critical current distribution and correlation of the overalln valueto the overall critical current from the distribution of local critical currents and the correlation of the localn valueto the local critical current by a Monte Carlo simulation. The measured average values of critical currentand n value at each bending strain and the correlation ofn value to critical current were reproduced well by the present simulation, while thedistribution of critical current values was reproduced fairly well but not fully. The reasonfor this is discussed.