考虑介电常数影响的GMA内部磁场特性分析

以Maxwell’s方程为基础，结合超磁致伸缩材料压磁方程，建立了考虑介电常数、预压应力等参数的超磁致伸缩材料内部磁场径向分布模型，并对其进行了理论分析和数值仿真.讨论了介电常数、预压应力、激励频率等参数对材料内部磁场分布及滞回特性的影响.结果表明，超磁致伸缩材料径向内部磁场分布具有明显的集肤效应和滞回特性；受电导率与介电常数共同影响，材料的磁场分布出现了双峰现象；沿磁致伸缩材料半径增大方向，外激励磁场与材料内部磁场的滞回特性逐渐减弱，磁场损耗随之降低；随着预压应力的增大，材料内部的集肤效应逐渐减小.

Inner Magnetic Field Characteristics of Giant Magnetostrictive Actuator Considering Permittivity Effects

Based on the Maxwell’s equation， the inner magnetic field radial distribution model of giant magnetostrictive actuator was built by combining with piezomagnetic equations， in which the permittivity， compressive prestress of the material were introduced. The theoretical analysis and numerical simulation of the model were done， and the influences of the material characteristic parameters on the material inner magnetic field and hysteresis characteristics were discussed. The results showed that the inner magnetic field radial distribution of giant magnetostrictive material (GMM) has obvious skin effect and hysteresis characteristics. Under the effects of conductivity and permittivity， the phenomenon of dual peak is found in magnetic field distribution of GMM. Along with the radius direction of GMM， the hysteresis characteristics between excitation magnetic field and inner magnetic field gradually become weak， and the magnetic loss decreases. The skin effect of GMM decreases with the increase of compressive prestress.