Analysis of the correlation betweenn-value and critical current in bent multifilamentary Bi2223 composite tape based on a damage evolution model

The change in n-value and critical current with bending strain and the relation of n-value to critical current of bending-damaged Bi2223 composite tape were studied experimentally and analytically. The n-value of the bending-damaged Bi2223 filamentary composite tape decreased very slightly with increasing bending strain and with decreasing critical current, in comparison with that of tension-damaged tape. To describe the experimental result for bending-damaged tape, a damage evolution model was applied in which the steep tensile-strain variation in the thickness direction, the shape of the core into which the superconducting filaments are bundled and the damage strain parameters obtained from the analysis of the tensile stress?strain curve were incorporated. The measured change in n-value and critical current with bending strain and the relation of n-value to critical current under applied bending strain were described satisfactorily by the present approach.