基于虚功原理的Galfenol悬臂梁建模与带载特性研究

研究了带载条件下Galfenol驱动器的磁机耦合建模方法,利用离散型能量均分模型(Discrete energy-averaged model)对Galfenol的磁滞非线性和饱和非线性进行建模,可以同时描述合金对于磁场和应力的依赖性。采用虚功原理将能量均分模型与驱动器的结构模型进行动力学耦合,研究了带载条件下驱动器的输出特性,并对不同Galfenol覆盖比时驱动器的驱动能力进行了研究,将计算结果与稀土超磁致伸缩材料(Terfenol-D)和压电陶瓷进行了对比。研究结果表明,驱动器的带载能力随着Galfenol悬臂梁材料覆盖比的增加而增加,材料内部承受的张力也随之增大;Galfenol合金良好的机械性能可以克服负载增加时所承受的张力的变化,解决其他智能材料易产生的失效问题。

Coupled Model and Characterization of Loaded Galfenol Beam Actuator Based on Virtual Work Principle

Galfenol is a magnetostrictive material which can be safely operated in tension, compression and shear. The coupled modeling framework of a loaded Galfenol actuator was studied. Field and stress dependent hysteresis and saturation were modeled with the discrete energy-averaged model. The dynamic model was developed by coupling the structural model with the energy-averaged model. Coupled governing equations were obtained by employing the virtual work principle and the model was discretized with Galerkin method. Simulation results showed that the proposed model had proper accuracy to predict the response of the beam actuator. In order to analyze the characteristics when the actuator was loaded with different forces, the output characterization of the loaded Galfenol actuator was studied by using different coverage ratios of the Galfenol cantilever. Calculation results were compared with Terfenol-D and the piezoelectric ceramics. It was shown that the load capacity and the internal tension of the actuator were increased by increasing the coverage ratio of the Galfenol cantilever. With a constant load, the actuator can no longer output positive displacement when the coverage ratio was relatively small. When Galfenol was loaded with tension, simulation results showed that the internal stress distribution exceeded the yield strength of both Terfenol-D and piezoelectric ceramics. The mechanical strength of Galfenol alloy ensured the material safety when the tension was changed due to the increase of the external loads.