Local and overall critical current and n-value of DyBCO coated conductor under applied tensile strain

Under applied strain/stress, extent of damage varies with location in a sample. Accordingly, overall critical current and n-value of a sample depend on extent of damage of local sections. The present work aimed to reveal the correlation of critical current and n-value of overall sample to those of local sections in DyBCO coated conductor. Critical current and n-value were measured for the voltage probe distances 45 and 15 mm, respectively, at 77 K in a self magnetic field. Both critical current and n-value beyond irreversible strain (approximate to 0.32%, corresponding to stress 320 MPa) decreased significantly with applied strain/stress. The reason for this was accounted for by the increase in crack size, accompanied by increase in shunting current. While the local critical current and n-value were different from section to section due to the difference in extent of damage, the relation of overall critical current and n-value to the local ones was described comprehensively by combining the Fang model with a voltage summation approach. (C) 2011 Elsevier B.V. All rights reserved.