兰州大学机构库 >土木工程与力学学院
第二类超导材料力学变形下 磁通与涡旋特性分析
Alternative TitleAnalysis of Magnetic Flux and Vortex Characteristics of Type-II Superconducting Materials under Mechanical Deformation
冯青
Thesis Advisor王省哲
2015-05-28
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword第二类超导材料 力学变形 非线性耦合TDGL方程 数值分析 磁通与涡旋特性
Abstract本文采用time-dependent Ginzburg-Landau (TDGL)理论研究了第二类超导材料力学变形下的磁学性能。基于混合变分原理,获得第二类超导材料考虑变形影响的控制方程与边界条件;运用有限元数值计算模型分析了第二类超导材料的磁通与涡旋特性。首先,针对半无限大超导结构运用有限元数值方法求解非线性耦合TDGL方程,讨论了线弹性变形与磁场对序参量 、总能量的影响。结果表明:预应变与外加磁场对可变形超导材料的超导特性与能量均有较为显著的影响。其次,针对磁场中受约束情形的可变形无限长超导材料开展数值研究,考虑TDGL方程与弹性变形场的耦合,讨论能量与总能量密度的变化规律,给出耦合系数对序参量、磁矢势、应变与能量影响结果。研究表明:在可变形超导材料中,超导冷凝态与晶格变形之间的相互作用不可忽略;序参量随外加均匀磁场的增强而减小,应变随磁场的增强而增大;耦合效应对序参量、磁矢势和系统能量密度均有一定影响。最后,开展带孔超导二维薄板结构磁通涡旋动力学研究,给出超导薄板变形与孔洞附近应力集中对超导特性与涡旋动力学行为影响。结果表明:预应力和超导材料内部的应力集中对涡旋分布、涡旋动态与序参量有重要影响;椭圆孔长短半轴比的变化不仅影响涡旋数目而且影响涡旋的稳态构型。
Other AbstractIn this study,the time-dependent Ginzburg-Landau (TDGL) theory is used for investigating superconducting magnetic properties of type-II superconducting materials under mechanical deformation.By means of the manipulation of the mixed,all governing equations and boundary conditions of type-II superconducting materials under mechanical deformation are derived.A finite element simulation approach was further developed to analyze the problem related to magnetic flux and vortex characteristics and behavior of type-II superconducting materials.Firstly,the finite element numerical approach for a half-plane superconductor is performed to capture the order parameter dependence on the elastic deformation and applied magnetic field by solving the time-dependent Ginzburg-Landau (TDGL) equations.At the same time,the effects of the elastic deformation and applied magnetic field on the total energy are discussed.The results show that the pre-strains and applied magnetic fields have a significant impact on the property and energy of deformable superconducting materials.Then the nonlinear and coupled TDGL equations and elastic field governing equation are solved for a deformable infinite superconductor with restriction at edges.The effects of applied magnetic fields on the all different kinds of energies and the total energy density are discussed in detail.Meanwhile the effects of the coupling parameter on the order parameter,the magnetic potential,the strain and the energy are also revealed.The results showed that the deformation caused by the interaction of the superconducting condensate with deformations of the crystal lattice cannot be ignored in the deformable superconducting materials.The order parameter decreases with applied magnetic field increasing,but the strain have the opponent variation.The coupling effect has a certain influence on the order parameter,the strain,and total energy of superconducting materials.Finally,the magnetic flux vortex dynamics in a two-dimensional superconducting thin plate with a hole have been demonstrated numerically,the effect of deformation and stress concentration on the superconducting properties and the vortex dynamical behavior are revealed.The results showed that the pre-strain has a remarkable influence on the flux vortex distribution and the vortex dynamics.The axle of the ellipse holes effect not only the number of vortices but also the steady configuration of vortex.
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/226588
Collection土木工程与力学学院
Recommended Citation
GB/T 7714
冯青. 第二类超导材料力学变形下 磁通与涡旋特性分析[D]. 兰州. 兰州大学,2015.
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