Abstract:

In the gradient DC magnetic field, the order of the magnetic force for the shield made from soft magnetic material was estimated. The magnetic force on a cuboid shield made from pure iron was studied by the finite element analysis (FEA) and experimental test. The preliminary results show that for a cuboid shield with inner dimension of 100mm×100mm×150mm and thickness of 20mm, placed within a DC magnetic field of about 0.2 T with average gradient 0.03T?m?1, its magnetic force is about 184N, close to its own gravity force. The analysis and test results show the magnetic force increases together with the field strength. The analysis results deviate from the experiment by about 21% under 0.2T field. Therefore, considering proper margins, FEA is an effective and reliable method to estimate the magnetic force exerted on shield by a gradient DC field.

Key words: Magnetic force, Finite element analysis, Magnetic shield

摘要：

在有梯度的静磁场中，对由软磁材料制作的磁屏蔽罩所受的静磁力的量级进行了评估。使用有限元分析和实验测试的方法研究了纯铁方形屏蔽罩在梯度静磁场中的受力情况，结果表明：把内腔尺寸100mm×100mm×150mm、罩体厚度为20mm的方形屏蔽罩放置在强度约为0.2T、梯度为0.03T?m?1的磁场中，其所受的静磁力约为184N，与其自身重力相当；静磁力随磁场强度的升高而增大；有限元分析与实验测试结果的偏差在0.2T背景磁场下约为21%。因此，在考虑一定余量的情况下，使用有限元计算评估屏蔽罩在静磁场中的受力情况是一种有效和比较可靠的方法。

关键词: 磁屏蔽罩, 磁力, 有限元分析