轴对称高场超导磁体电磁应力有限元分析方法

核磁共振成像和核磁共振谱仪是高场超导磁体的主要应用领域.高场超导磁体通常具有较高的磁场和运行电流,在运行过程中超导线会产生较高的电磁应力,其临界特性将发生退化,影响磁体的稳定性.开展高场超导磁体的电磁应力精确分析显得尤为必要.本文发展了一种快速有效的有限元分析方法,第一步,为整个超导磁体系统建立平均有限元模型,采用传统的电磁-结构耦合方法求解电磁应力,获得最大应力位置;第二步,对最大应力所在的超导线圈建立详细有限元模型,采用单积分-结构分析方法精确求解每一组分中电磁应力.基于该模型研究了500 MHz NMR超导磁体的电磁应力.该分析方法也可以用于超导磁体冷却过程中的热应力分析.为高场超导磁体设计和建造提供有益的理论依据.

Finite Element Analysis Method for Electromagnetic Stress of Axisymmetric High Field Superconducting Magnet

Nuclear magnetic resonance Spectrometer and nuclear magnetic resonance imaging are the main applications of high field superconducting magnets. Because the high-field superconducting magnets usually have a high magnetic field and operating current, the superconducting wire will withstand higher electromagnetic stress during the operation. So that the critical characteristics of wire will be degraded, the stability of the magnet affected. It is necessary to carry out the precise analysis of the electromagnetic stress of the high field superconducting magnet. In this paper, a fast and effective finite element analysis method is developed. The first step is to establish the average finite element model for the whole superconducting magnet system. The traditional electromagnetic-structural coupling method is used to solve the electromagnetic stress and obtain the maximum stress position. In the second step, a detailed finite element model is established for the superconducting coil where the maximum stress is located. The single integral - structure analysis method is used to accurately solve the electromagnetic stress in each component. Based on this model, the electromagnetic stress of 500 MHz NMR superconducting magnet was studied. The analytical method can also be used for thermal stress analysis of superconducting magnets during cooling. Which can provide useful theoretical suggestions for the design and construction of high field superconducting magnets.