Investigation of Frictional Force Applied to Strands Surrounded by Other Strands and Tribological Analysis of Contact Surface in CIC Conductor
Investigation of Frictional Force Applied to Strands Surrounded by Other Strands and Tribological Analysis of Contact Surface in CIC Conductor
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DOI：
10.1109/tasc.2013.2291820
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发表时间：
2014-06
影响因子：
1.8
通讯作者：
Tsuyoshi Yagai;H. Kudo;K. Hamano;K. Yoshida;Shinji Hamaguchi;K. Natsume;T. Obana
中科院分区：
文献类型：
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作者：
Tsuyoshi Yagai;H. Kudo;K. Hamano;K. Yoshida;Shinji Hamaguchi;K. Natsume;T. Obana
在苏丹试验设施，对环向场线圈性能的评估一直在进行。在均流温度显著下降后，在导体的破坏性研究期间观察到不可预测的股线屈曲。屈曲方向垂直于洛仑兹力（LF），并且导致这一点的机制是由于由于股线材料和不锈钢导管之间的热收缩差异而发生的热收缩。我们之前的研究基于二维弦模型，并证明如果假设接触交叉处的总滑动量为80 μm，则观察到的2 mm股线弯曲可能导致股线屈曲。为了验证这一假设，我们制作了一个装置，用于测量在与几百千牛顿/米的LF相当的收缩力下股线之间的摩擦力（剪切力）。由裸铜绞线包围的直径为0.89 mm的铬涂层绞线的结果表明，当收缩力减小到最大LF的十分之一时，热收缩力将足以克服静摩擦力。滑动运动的机理可分为两个过程：管道内壁的分离和由于LF逐渐减小而与其他股线逐渐分离。摩擦学分析表明，当施加剪切力时，真实的接触面积增加了10%;这一结果将有助于我们评估导线股之间的接触电阻。
At the SULTAN test facility, the assessment of the performance of toroidal field coils has been progressing. Unpredictable strand buckling was observed during the destructive investigation of the conductor after significant degradation of the current sharing temperature. The buckling direction was perpendicular to the Lorentz force (LF), and the mechanism causing this was due to the thermal shrinkage occurring because of the difference in the thermal contraction between the strand material and the stainless steel conduit. Our previous research was based on a two-dimensional string model and demonstrated that the observed 2 mm strand bending could have led to strand buckling if the total amount of slide at the contact crossover was assumed to be 80 μm. To verify this assumption, we fabricated a device for the measurement of the friction force (shear force) between strands under a constriction force comparable to the LF of several hundred of kilonewtons per meter. The results for a Cr-coated 0.89 mm diameter strand surrounded by bare Cu strands indicated that the thermal contraction force would be sufficient to overcome the static friction force when the contraction force is reduced to a tenth of the maximum LF. The mechanism of the slide motion could be divided into two processes: separation of the inner wall of the conduit and the gradual separation from other strands due to a gradual reduction of the LF. A tribological analysis revealed that the real contact area increases by 10% when the shear force is applied; this result would help us evaluate the contact resistance between strands of conductors.