Influence of Bolt Positions and Electrode Structure in Yoroi-Coil Structure on Stress Distribution in an HTS Coil Winding
Influence of Bolt Positions and Electrode Structure in Yoroi-Coil Structure on Stress Distribution in an HTS Coil Winding
复制标题
Yoroi-线圈结构中的螺栓位置和电极结构对高温超导线圈绕组应力分布的影响
DOI：
10.1109/tasc.2017.2780839
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
S. Awaji
中科院分区：
文献类型：
--
作者：
M. Kato ;D. Miyagi;M. Tsuda;S. Awaji
大的环向应力会导致高温超导线圈绕组输运性能的恶化。提出了一种称为“Yoroi线圈”的高强度煎饼线圈结构。yoro -coil结构预计将减少施加在绕组上的电磁力和绕组外部线圈框架的体积。在无螺栓、无电极的理想“Yoroi-coil”结构中，研究了Yoroi-coil对环向应力减小的影响。然而，在实际的“Yoroi-coil”结构中，有电极和螺栓用于固定框架和加强线圈的外板。本文采用三维有限元法（FEM）对实际的带有螺栓和电极的yoro -coil结构的HTS线圈绕组进行了数值研究。数值计算结果表明，缠绕过程中产生的周向应变和环向应力与锚杆位置有关。绕组，特别是电极周围的局部应力较大。为了不使绕组产生局部较大的应力，电极的机械强度非常重要。在电极上添加螺栓可以有效地抵消电极处的应力集中。然而，电极处螺栓的最佳数量在很大程度上取决于线圈冷却过程中的热收缩。
Large hoop stress causes the deterioration of the transport properties of an high-temperature superconducting (HTS) coil winding. A high-strength pancake coil structure called “Yoroi coil” has been suggested. Yoroi-coil structure is expected to decrease the electromagnetic force applied to the winding and the volume of the coil frame at the outside of the winding. The effect of Yoroi coil on the hoop stress reduction has been investigated in an ideal “Yoroi-coil” structure without bolts and electrodes. In a practical “Yoroi-coil” structure, however, there are electrodes and bolts for fixing frames and reinforcing outer plates to the coil. In this study, the effect of the stress reduction of an HTS coil winding using the practical “Yoroi-coil” structure with the bolts and the electrodes was numerically investigated by 3-D-finite element method (FEM) analysis. Numerical results showed that the circumferential strain and hoop stress generated in the winding depended on the bolt location. Local large stress was applied to the winding, especially around the electrode. In order not to apply the local large stress to the winding, the mechanical strength of the electrode was very important. Adding bolts to the electrode was effective as the counterplan of stress concentration at the electrode. The optimal number of bolts at the electrode, however, largely depended on the thermal contraction during the cooling process of the coil.