Effect of axial tensile strain on self-field loss of Bi2223/Ag tapes

Abstract

The effect of axial tensile strain on self-field loss of Bi2223/Ag tape is studied. The axial irreversible tensile strain limit ( ε irr) is about 0.35%. When the applied axial strain is less than ε irr, the self-field loss curve with certain axial tensile strain is almost coincided with the curve of no axial tensile strain. When the applied axial strain is larger than ε irr, the self-field loss increases sharply. These experimental results can be explained by the relation between the loss and I c: when ε< ε irr, with the increase of ε the I c has little decrease, so loss has little increase; when ε> ε irr, the large strain causes the superconducting filaments delaminating from the silver matrix and the superconducting filament begins to disconnect, such structural damage causes a localized depression of critical current and gives rise to flux flow and ohmic loss contribution. Experimental results were compared with the Norris equation on the self-field loss, and the loss of no axial tensile strain has good agreement with the Norris elliptical geometry equation.