| Nb3Sn股线的多级螺旋结构及力学性能分析 |
| Alternative Title | The multi-helical structure and mechanical property analysis of the Nb3Sn strand
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| 董帅 |
| Thesis Advisor | 周又和
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| 2015-05-28
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| Degree Grantor | 兰州大学
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| Place of Conferral | 兰州
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| Degree Name | 硕士
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| Keyword | Nb3Sn 股线
多级螺旋结构
等效模量
接触
力学性能
有限元
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| Abstract | 作为超导磁体的核心组成部分，管内超导电缆(CICC)的超导性能对整个磁体系统的运行有着重要影响。在托卡马克装置中，纵场和中心场线圈采用了Nb3Sn超导股线复合而成的电缆。而Nb3Sn材料的超导性能对其自身的应变高度敏感。因此对Nb3Sn超导股线及其组成的电缆进行力学性能方面的研究有助于日后对超导磁体的设计优化和性能评估。得到了一级子缆(三元组)轴向受拉时内部股线的应变张量矩阵，讨论了轴向应变对股线变形后螺旋参数的影响;给出了各级子缆等效模量的变化。针对二级子缆内部的股线，讨论了螺旋参数对中心线曲率、挠率的影响；给出了一级子缆弯曲时股线分布力与自身弧长的关系，并与轴向拉伸情况进行了对比；给出了螺距变化时股线间挤压产生的径向变形。研究了四级子缆受轴向拉伸载荷作用时内部的接触情况,给出了两种类型股线在不同子缆间接触力作用下时临界电流密度的变化。利用了comsol软件对内锡法制备的股线进行了有限元建模，考察了不同螺旋结构下股线受拉时整体以及内部的应力应变，讨论了螺距的变化对二级螺旋结构股线的力学性能影响；建立了各级子缆的等效模型，对子缆受拉伸载荷作用进行了数值模拟，得到了各级子缆的应力-应变曲线并与理论结果进行了对比。 |
| Other Abstract | As a core part of the superconducting magnets, the superconducting properties of the cable-in-conduit conductor (CICC) plays an important role during the operating of the magnet system. In the tokamak device, the longitudinal field and center field coils adopted the superconducting cable which are composited by the Nb3Sn strands. The superconducting properties of the Nb3Sn are highly sensitive to strain which determines the overall performance of the superconductor cables when working in low temperature and high magnetic field. Therefore, the study of the mechanical properties of the Nb3Sn strand and CICC will contribute to the design optimization and performance evaluation of the superconducting magnet in the future. A theoretical model is proposed based on the thin rod theory to analyze the changing of the equivalent moduli of the sub-cables during axial stretching. After that, the expressions of the center line of the strand in second-stage sub-cable was derived according to the differential geometry theory and the effects of the related parameters to the curvature and torsion of the center line was discussed. Based on this, the distributed forces of the strand when the first-stage sub-cable flexed are derived and calculated. The compressional strain between the strand has also been given. In reality, the internal contact of the sub-cable is complicated, in this paper we study the contact situation in the four-stage sub-cable when the cable subjected to axial tension. We shows the critical current density reduction of two types strand when suffer different contact forces in order to highlight the effect of the contact force on the superconducting properties of the strand. Finally we establish the finite element model of the internal-thin-process strand by using the comsol software and examines the stress and strain of the strand globally and locally. We also discuss the effects of the change of the first-stage pitch length to the mechanical properties of the second-stage helical strands. At last, we establish the equivalent model of the sub-cable at each stage. |
| URL | 查看原文
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| Language | 中文
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| Document Type | 学位论文
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| Identifier | https://ir.lzu.edu.cn/handle/262010/226747
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| Collection | 土木工程与力学学院
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Recommended Citation
GB/T 7714 |
董帅. Nb3Sn股线的多级螺旋结构及力学性能分析[D]. 兰州. 兰州大学,2015.
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