Critical-Current Degeneration Dependence on Axial Strain of Bi-based Superconducting Multi-filamentary Composite Tapes

Abstract

Superconducting materials are always severely restricted in practical engineering applications due to their carryingcurrent degradation under mechanical loads. Based on Ekin's exponential model and Weibull's distribution function, we propose an empirical degradation model for describing the mechanical deformation influence on the critical-current of Bi-based superconducting multi-filamentary composite tapes under axial loading. The critical currents of superconducting tapes depending on the axial strain are investigated analytically. It is shown that the predictions by the developed degradation model agree with the experimental data, in the processes of axial mechanical loading and unloading on the samples. The effect of the critical tension and compression damage strains on the normalized critical currents is also discussed.

Stress, strain and electromechanical analyses of (RE)Ba2Cu3Oxconductors using three-dimensional/two-dimensional mixed-dimensional modeling: fabrication, cooling and tensile behavior

“…Furthermore, irreversible degradation of I c in both BSCCO-based (e.g. Bi-2212 and Bi-2223) and REBCO conductors has been studied using a statistical approach based upon the Weibull statistics [31,32,[42][43][44][45]. Here a critical current phenomenological model that combines the Ekin power-law formula and the Weibull distribution function with the REBCO conductor model is used to predict the electromechanical behavior of I c in REBCO conductors across the entire strain range.…”

“…Ignoring the linear deformation effect on the REBCO cross-section area, and assuming a uniform distribution of current on the REBCO layer, the normalized critical current A statistical approach based upon the Weibull distribution function has been used to characterize the effective area of undamaged superconducting region under deformation in BSCCO-based conductors [42][43][44][45], and the irreversible degradation of I c in both BSCCO-based and REBCO conductors [31,32]. The statistical ratio of undamaged superconducting cross-section area to the before-damaged superconducting cross-section area under uniaxial loadings, S S , Figure 13 compares the simulation result calculated by (24) against the experimental data taken from [8] for the applied strain dependence of (normalized) critical current.…”

Theory analysis of critical-current degeneration in bended superconducting tapes of multifilament composite Bi2223/Ag

“…The shape parameters c and t of Weibull's distribution function are usually constrained less than 6 [21]. In our study, they are assumed to be equal each other for simplicity, that is, c = t = 2, which gives good predictions coincident with experiment data for Bi-based superconductor composite tape under both tension and compression states [25]. The scaling parameters of Weibull's distribution function e c , e t are the fitting parameters based on tensional and compressive tests.…”

“…For a bent Bi2223-composite tape, ideally, one side of the neutral axis is stretched, and the other side is compressed. From the view of damage of fiber-reinforced composites, the ratio of the number of undamaged superconducting filaments to the total number of superconducting filaments under tension and compression conditions satisfies Weibull distribution, as follows [22][23][24][25]:…”

Mechanical and critical current characteristics of high-strength Bi 2 Sr 2 Ca 2 Cu 3 O 10+δ multi-filamentary tapes reinforced with thicker Ni-alloy laminations with various pre-tensions

“…Then, Gao et al combined the damage evolution model [33] with the Weibull-type damage distribution [34] and reproduced I L c (ε app ) measured by bending dies and changes in I L c and I UL c during loading-unloading cycles [35]. Gao et al also reported a model that involves the uniaxial strain dependence of J c and the Weibull-type damage evolution [36].…”