时变电磁场中电磁材料所受斥力和吸力的分析

Attractive and Repulsive Forces of Electromagnetic Materials in Time-Varying Electromagnetic Fields

电磁材料在时变电磁场中所受的电磁力可分为斥力分量和吸力分量,这两种力的分量可由洛仑兹力和开尔文力表达式导出。在正弦稳态场中,斥力分量和吸力分量均含有直流分量和交流分量,两个直流分量相互削弱;在理想情况下,两个分量完全抵消,电磁材料所受的平均合力为零。此现象可用于减小时变电磁场中电磁材料的受力与振动。通过理论分析和数值计算,比较了频率、材料磁导率和电导率对电磁物质所受吸力和斥力的影响;模拟计算了铁磁材料与良导体材料叠层板的受力,给出了一定频率下使平均合力为零的叠层板的厚度比例情况。

The electromagnetic force of electromagnetic materials owns the attractive and the repulsive components, which can respectively be introduced from the Lorentz force and the Kelvin force formula. In the harmonic fields, the attractive and the repulsive components both own the DC and the AC components, which can cancel out with each other to reduce the total force. The contributions or influences of the frequency, the magnetic permeability and the electric conductivity of the material to the attractive and the repulsive force in time-varying fields are analyzed and simulated by the numerical simulations of FEM. The electromagnetic forces of ferromagnetic material sheet with another conductor sheet together are also simulated. The result shows that the total time average electromagnetic force could be reduced greatly in some cases, which is useful to reduce the vibration of the materials.