为提高超磁致伸缩致动器(GMA)的精度, 描述其在动态和准静态环境下的复杂磁滞行为, 设计了具有精密位移输出的GMA, 建立了包含磁滞及涡流损失的动态非线性多场耦合模型。首先, 采用模块化方法设计了GMA; 然后, 利用热力学理论和能量守恒定律, 建立了超磁致伸缩材料非线性多场耦合本构模型; 最后, 通过分析材料非线性本构行为与系统结构动态行为间的耦合过程, 提出了GMA的动态非线性多场耦合模型。实验分析了能量损失及预紧力对系统特性的影响规律。结果表明: 预紧力可改善系统输出特性且存在最佳预紧状态; 建立的模型能够较准确预测位移, 平均相对误差约为4.5%。另外, 随着频率增加, 异常和涡流能量损失以及磁滞量会增大, 磁滞行为源于磁畴不可逆运动过程中的能量损失。实验还显示: 对于精密GMA系统, 不能忽略高频涡流效应。建立的模型较准确地描述了动态及准静态环境下GMA的复杂磁滞行为, 由于考虑了材料本构行为耦合和系统动态行为耦合, 进一步提高了GMA系统的精度。

To improve the precision of a Giant Magnetostrictive Actuator (GMA) used in a precision machining field and to describe its complex hysteresis behavior under dynamic and quasi-static conditions, a GMA with an accurate displacement output was designed. By consideration of both the eddy current losses and hysteresis, a dynamic nonlinear model with multi-field coupling effects was also established. Relationships among energy loss, hysteresis and frequency and other working performance were studied. Firstly, the GMA was designed through the modular method. Then, based on the thermodynamic theory and energy conservation law, a nonlinear multi-field coupling constitutive model for giant magnetostrictive materials was established. Finally, a nonlinear multi-field coupling dynamic model for the GMA was proposed through analyzing the coupling process between the nonlinear constitutive behaviors of materials and the dynamic behavior of system structure. The effects of energy loss and pretightening force on the system characteristics were analyzed. The experiment results show that pretightening force improves the output characteristic of GMA and there is an optimal preloaded state. The model predicts the displacement accurately and the average relative error is about 4.5%. The hysteresis behavior is attributed to the energy losses generated in the irreversible motion process of domain. With the increase of frequency, the abnormal and eddy current energy losses and hysteresis increase. The eddy current effect can not be ignored when precision GMA is under a high frequency. The model describes the complex hysteresis behaviors of the GMA under dynamic and quasi-static conditions accurately. As the materials constitutive coupling and structures dynamic behavior coupling are considered, the precision of the GMA is improved greatly.