Indigenously developed bending strain setup for I-V characterization of superconducting tapes and wires

An indigenously developed bending strain setup to examine the effect of pure bending on critical current of superconducting tapes and strands has been presented in this paper. This set up is capable of applying various bending radius in situ at cryogenic temperature with rack and pinion gear mechanism. The bending strain applied on samples can be controlled externally by rotational input which is transferred in the form of bending radius during experiments. The working principle, design and optimization of this set up have been discussed. The performance and validation of this setup has been done on various HTS tapes and copper strands at 77 K in actual experimental facility. Effect of bending radius (15.5 mm - 48 mm) i.e. strains and ramp rate (2 A/s – 8 A/s) is observed on current capability of various HTS Tapes. It is observed that in uniform bending condition, degradation in current carrying capacity BSCCO and Di-BSCCO (∼ 30 %) is more as compare to YBCO (∼ 2.75 %) at 77 K. The effect of pure mechanical strain has been experimentally observed and presented.