根据超磁致伸缩材料的弹性模量E随环境磁场与应力状态改变的特性,建立了考虑△E效应的磁致伸缩作动器动力学模型.不同于一般的参数振动和强迫振动,该模型的特点是同时存在参数激励和外激励.利用摄动法对该模型求解与分析,获得了作动器的参数振动频谱特性和共振频率.通过稳定性分析并考虑外激励的作用分析了此类结构在谐波与次谐波共振频率激励时的危险性,其中驱动电流频率为1/2固有频率时需考虑次谐波共振幅值是否会超出安全范围.所得结论可为磁致伸缩作动器及其智能结构的使用和设计提供参考.
Elastic modulus E of giant magnetostrictive materials changes with themagnetic field and the stress, which is known as the AE effect. This paper proposes a dynamic model of magnetostrictive actuator that takes into consideration the AE effect, The feature of the model is the existence of both parametric excitation and external excitation, which is different from ordinary parametric vibration or forced vibration. The perturbation method is applied to solve and analyze the model. The spectrum charateristics and resonance frequency of parameter vibration are obtained. The danger of such structures un- der excitation of sub-harmonic resonance is analyzed by means of stability analysis in combination with an analysis based on the stability theorem considering external excitation. The amplitude of sub-harmonic resonance is considered when the fre- quency of the driving current is equal to 1/2 inherent frequency of the actuator. The conclusions obtained can be used as ref- erence in the design of giant magnetostrictive actuators and smart structures with magnetostrictive materials.