复合Bi系超导多芯带材轴向荷载作用下的临界电流退化模型与分析

Critical Current Degradation Model and Analysis of Bi-Based Superconducting Multi-filamentary Composite Tape under Axial Load

超导材料由于在外部载荷作用下表现出的超导性能退化效应严重制约了其工程实际应用。基于脆性纤维金属基增强复合材料损伤理论,应用Weibull分布函数建立了轴向荷载作用下的复合多芯Bi系超导带材的力学变形对临界电流影响的退化模型。给出了轴向加载和卸载过程超导带材临界电流随轴向应变的变化关系;并对超导带材不同初始损伤以及预应变情形下的临界电流随轴向应变的变化关系和退化进行了理论预测,能够给出与实验结果吻合良好的轴向应变对临界电流的退化影响。

Superconducting materials are always severely restricted in practical engineering applications due to the degradation of superconductivity under external mechanical loads. Based on the damage theory of fragile fiber reinforced metal matrix composites and the Weibull distribution function, a degradation model to describe the mechanical deformation influence of the Bi-based superconducting multi-filamentary composite tape on its critical current under axial load was proposed. The critical currents of superconducting tape with the axial strain in the processes of axial loading and unloading were analyzed. The degradation of the critical current of superconducting tape under the conditions of different initial damages and pre-strains was predicted theoretically. It is shown that the theoretical model we developed can predict well the degradation of critical current of the Bi-based superconducting multi-filamentary composite tape with axial strain. The results are in good agreement with the experimental data. The present investigation will be helpful for superconducting composites in applications