【作者】 阳昌海；

【导师】 文玉梅；

【作者基本信息】 重庆大学 ， 光学工程， 2008， 硕士

【摘要】 磁电复合材料因其显著的磁电效应受到越来越多的关注。磁电复合材料可以用于磁电换能器,如磁场传感器等。研究发现磁电复合材料的磁电效应和偏置磁场密切相关。本文应用超磁致伸缩材料的非线性本构模型和层合材料的等效电路相结合的方法,分析了偏置磁场对磁电复合材料谐振磁电效应的影响,并进行了实验验证。本文主要工作如下:对比了超磁致伸缩材料的四种宏观唯象模型,发现Z-L模型能够很好的模拟超磁致伸缩材料的非线性特性。根据Z-L模型推导了超磁致伸缩材料的动态杨氏弹性模量、动态压磁系数和动态磁导率与外加磁场的关系。根据压电方程、压磁方程和动力学方程,运用等效电路法得到了超磁致伸缩/弹性/压电层合材料的等效电路。由于在层合材料的振动过程中,机械损耗是不可忽略的,则应用复参数法引入机械损耗,得到可以应用于层合材料谐振状态的包含损耗的等效电路,进而获得了层合材料的谐振频率方程和谐振磁电电压转换系数。把超磁致伸缩材料动态杨氏弹性模量和动态压磁系数代入谐振频率方程和谐振磁电电压转换系数中,得到谐振磁电效应和偏置磁场的关系。分析表明,偏置磁场通过影响超磁致伸缩材料的动态杨氏弹性模量而改变材料的谐振频率;偏置磁场通过影响超磁致伸缩材料的动态压磁系数和动态杨氏弹性模量而改变谐振磁电电压转换系数。制作了Terfenol-D/铍青铜/PZT-5H实验样片,在不同偏置磁场下进行了实验。通过理论和实验对比分析得到如下结论:①随着偏置磁场的增大,层合材料的谐振频率先逐渐减小后逐渐增大;②随着偏置磁场的增大,层合材料的谐振磁电电压转换系数先逐渐增大后逐渐减小;③存在最佳偏置磁场使层合材料的谐振磁电电压转换系数最大。更多还原

【Abstract】 Magnetoelectric (ME) composite materials have received increasing attention because of its remarkable ME effect. ME composite materials can be used for magnetoelectric transducers, such as magnetic field sensors. The researches show that the ME effect in ME composite materials is closely related to bias magnetic fields. By combining nonlinear constitutive model for giant magnetostrictive material (GMM) with equivalent circuit of laminated materials, this paper analyzes the influence of bias magnetic field on the resonant ME effect of composite material, and compares the theoretical values with experimental results. The main work is as follows:Comparison is made on four kinds of macroscopic phenomenological models for GMM. It is found that the Z-L model is more accurate than other models in simulating nonlinear characteristics of GMM. Dynamic Young’s modulus, dynamic piezomagnetic coefficient and dynamic permeability of GMM are derived based on the nonlinear constitutive model for GMM.Based on the piezoelectric, piezomagnetic and dynamic equations, the equivalent circuit of magnetostrictive/elastic/piezoelectric laminate composite is obtained. Because the mechanical loss can not be neglected in the vibration process of the laminate composite, it is necessary to consider it in the equivalent circuit with the introduction of complex parameters. Such equivalent circuit with loss can be used to characterize the laminate composite at resonant frequency. We derive the resonant frequency equation and the ME voltage coefficient expression of the laminate composite.The dynamic Young’s modulus and the dynamic piezomagnetic coefficient are substituted in the resonance frequency equation and the ME voltage coefficient expression. Thus the relationship between ME effect and bias magnetic fields can be obtained. It is shown that the bias magnetic field changes the resonant frequency by affecting the dynamic Young’s modulus of GMM; the bias magnetic field changes the resonant ME voltage coefficient by affecting both the dynamic Young’s modulus and the dynamic piezomagnetic coefficient of GMM.Terfenol-D/beryllium bronze /PZT-5H sample is made. And its magnetoelectric performance is measured under different bias magnetic fields. By comparing the theoretical analysis with experimental results, it is showed that:①The resonant frequency of the composite firstly decreases, then increases as the bias magnetic field increases;②The resonant ME voltage coefficient of the composite increases firstly, then decreases as the bias magnetic field increases;③There is an optimal bias magnetic field at which the resonant ME voltage coefficient reaches its maximum.更多还原