超导复合材料非线性力电行为及临界性能退化机理研究

Due to the outstanding electromagnetic properties, superconducting materials have shown a great potential for applications in the electricity, energy and transportation area. Superconducting materials always operate under extreme conditions like strong magnetic fields, extremely low temperatures and large transport current, and has strong nonlinear electromagnetic properties which are sensitive to the external fields, all of these made the safe, stable and reliable operation of superconducting materials key issues in the design and application of superconducting devices. Superconducting composite material subjected to magnetic field and external loads undergoes deformation, damage, microcracks and the accompanied reversible and irreversible degradation of superconducting critical properties, while the micro-mechanism for the irreversible degradation of superconducting critical properties is not clearly understood yet. This proposed project will study the electromechanical coupling behavior and the critical properties degradation of superconducting composite materials through theoretical modeling and numerical simulations. We will propose a theoretical model to characterize the effective electromechanical coupling properties of superconducting composite materials, discuss the influences of internal microstructures on the electromechanical properties and its coupling mechanism of superconductors, and develop a quantitative analysis method to simulate the deformation, damage, fracture and the performance degradation of superconducting composite materials under extreme conditions. Carrying out this project will make theoretical foundation on the performance prediction and evaluation, optimum design and large scale application of superconducting composite materials.

超导材料由于具有优异的电磁性能在电力、能源和交通等领域具有广阔的应用前景。由于常处于强磁场、极低温、大电流等极端环境，加上电磁性能的强非线性特征及其对外界环境的敏感性，使得超导材料的安全稳定运行成为当前超导器件与装置设计和应用过程中亟需解决的关键问题。在磁场及外加载荷作用下超导复合材料内部会发生变形、损伤和微裂纹以及临界性能的可逆和不可逆退化，其中临界性能不可逆退化的微观机理有待进一步的研究和揭示。本项目拟通过理论建模和定量数值分析对超导复合材料的力电行为及临界性能退化进行研究，建立表征超导复合材料宏观有效力电性能参数的理论模型，探讨变形和材料内部微结构对超导体力电性能及其耦合特性的影响规律，为极端环境下超导复合材料的变形、损伤和破坏与临界性能退化研究提供定量分析方法。通过本项目的研究为超导复合材料在服役环境下的性能预测与评估，结构优化设计和大规模工程应用提供理论基础。

超导材料由于其优异的电磁性能在能源、交通、国防以及大科学装置等领域具有广泛的应用前景。超导装置运行在极低温、强磁场等极端环境下，强磁场下超导体会承受巨大的电磁力以及热应力等，加之超导材料临界性能的环境敏感性，因此保持其结构和功能的安全性、可靠性和稳定性对于其工程应用至关重要。本项目针对典型超导材料在力-热-电-磁多物理场环境下的非线性力电性能展开研究，项目执行期间主要开展了以下几个方面的工作：（1）超导复合材料有效力电性能的理论建模与预测。基于复合材料细观力学理论并结合超导复合股线的结构特征，建立了表征和分析超导复合股线有效力电性能的多层级等效模型，给出了超导股线临界传输性能退化规律。（2）微结构对超导薄膜宏观电磁行为及磁热不稳定行为的影响研究。结合超导体的麦克斯韦电磁理论、热传导方程以及弹性力学理论，并引入表征材料损伤及断裂行为的相场断裂模型，建立了对超导材料在力-热-电-磁多物理场耦合环境下结构变形、损伤、破坏以及磁热稳定性等行为进行仿真分析的理论框架，给出了超导块材在极端载荷作用下的损伤和微裂纹等的演化行为。（3）超导材料微观磁通动力学行为及微结构损伤演化研究。基于Ginzburg-Landau理论，通过建立理论模型并利用有限元仿真分析，研究了超导材料在多物理场环境下的磁通动力学行为和微结构损伤演化等行为及其有效电磁性能。