随着超导体俘获磁场和临界电流密度等性能的不断提升，超导材料在生物、医学和能源等领域有着巨大的应用潜力。由于超导材料的工作环境为低温和强磁场的极端条件，在设计及工作过程中的力学行为及稳定性已经成为超导磁体及结构安全运行的基础性问题。在强磁场作用下超导体内较大的洛伦兹力是限制发展高磁场超导磁体的主要原因之一。另一方面，超导体中力学变形与超导电性具有明显的耦合效应，力学应变会导致临界电流密度的显著退化。.本项目拟通过理论建模和定量分析对超导薄膜基底结构中的关键力学问题展开研究。建立超导薄膜基底结构中界面裂纹和内部裂纹问题的理论模型，探讨洛伦兹力和热应力共同作用下薄膜基底结构中裂纹的断裂行为，揭示影响裂纹扩展的主要因素；建立超导薄膜中临界电流密度与力学变形之间的表征关系，分析复杂变形和磁场对临界电流密度的影响。通过开展本项目的研究，为薄膜基底结构中力学行为的研究和相关超导结构的设计提供了理论基础。

With the development of the field-trapping and the critical current density in the superconductors, superconducting materials have a great potential for applications in biology, medicine and energy. Since the working condition for superconducting materials is extremely low temperature and high magnetic field, the mechanical behavior and instability have become a basic problem for safe operation of the superconducting magnet and structure. Large electromagnetic force restricts the advance of superconducting magnet with high magnetic field. On the other hand, the coupling behavior between the mechanical deformation and the superconductivity is obvious, and the strain will reduce the critical current density. .This proposed project will study the key mechanical problems in the superconducting film-substrate structure using theoretical modeling and quantitative analyzing. We will establish the theoretical models for the interface crack and internal crack problems, and investigate the fracture behavior under the electromagnetic force and thermal stress. Then, the key factor for the crack propagation can be found. In addition, the relationship between the critical current density and the mechanical deformation is established, and the effects of the complex deformation and the magnetic field on the critical current density are investigated. By carrying out this project, the results obtained will provide a theoretical foundation for the research of the mechanical behavior for the film-substrate structure and the design of the superconducting structure.