Winding strain analysis for YBCO coated conductors
Winding strain analysis for YBCO coated conductors
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DOI：
10.1088/0953-2048/23/4/045017
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发表时间：
2010-04
影响因子：
3.6
通讯作者：
W. Markiewicz;C. Swenson
中科院分区：
文献类型：
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作者：
W. Markiewicz;C. Swenson
对螺线管线圈中 YBCO 涂层导体的绕组应变进行了分析。为薄饼和层绕线圈中出现的弯曲应变开发了表达式作为相关参数的函数。径向薄饼或螺旋层缠绕的弯曲应变直接来自薄梁的弯曲分析。在绕组中存在径向台阶的情况下（如接头处可能发生的那样），引入了该台阶的简单模型，并导出了相关弯曲应变的表达式。对于层绕，建议采用两种层端匝模式，以满足设计目标并避免径向构建干扰。导出了宽方向弯曲应变的表达式。对报告的 YBCO 临界电流应变容差进行审查，以量化弯曲应变的可接受极限。使用导出的表达式计算薄饼绕组和层绕组的各种配置的弯曲应变，并与测量的不可逆应变进行比较。在大缠绕直径时，弯曲应变通常较低，但在小直径时弯曲应变会增加并成为设计约束。接头的位置在层缠绕模式的端匝区域中被识别。根据绕组的直径和端匝可用的空间，接头的存在可以大大增加端匝的弯曲应变。
An analysis is made of the winding strains for YBCO coated conductors in solenoid coils. Expressions are developed for the bend strains that occur in pancake and layer wound coils as a function of the relevant parameters. The bend strain for the winding of radial pancakes or helical layers follows directly from the bending analysis of thin beams. In the case that there is a radial step in the windings, as might occur at a joint, a simple model for the step is introduced and an expression for the associated bend strain is derived. For layer winding, two patterns of layer end turn are suggested to meet the design objectives and to avoid radial build interference. Expressions for the wide direction bend strain are derived. The reported strain tolerance of the critical current of YBCO is reviewed to quantify acceptable limits for the bend strain. Bend strains are computed for various configurations of pancake winding and layer winding using the derived expressions and compared to the measured irreversible strain. At large winding diameters, bend strains are generally low but are shown to increase and become a design constraint at small diameters. Locations for joints are identified in the end turn regions of layer winding patterns. Depending on the diameter of the windings and the space available for the end turn, it is shown that the presence of a joint can greatly increase the bend strain of the end turn.