【作者】 程磊；

【导师】 文玉梅；

【作者基本信息】 重庆大学 ， 仪器科学与技术， 2008， 硕士

【摘要】 磁电复合材料可以实现磁能与电能之间的相互转换,能够应用于磁场检测、微波泄漏监测、电磁场能量转换等领域。与颗粒混合结构相比层合结构具有更高的磁电电压转换系数,本课题组提出将片状磁致伸缩材料和压电材料复合到弹性基底上,构成一种采用弹性基底的三相磁电复合结构,相比磁致伸缩材料和压电材料层合的两相磁电复合结构,在谐振时该结构具用更高的磁电电压转换系数。针对这种三相复合结构,本文采用有限元方法,分析采用等截面弹性基底和采用尖楔形弹性基底的两种磁电复合结构的磁电特性。主要研究工作如下:1.应用有限元方法对压电问题的分析能力以及磁致伸缩-压电类比关系,分析采用基底复合结构的磁电效应。通过输入几何模型、选定单元类型、设置材料参数、划分网格、施加载荷和边界条件等步骤,建立了两种磁电复合结构的有限元分析模型。2.对两种采用弹性基底的磁电复合结构进行有限元分析,研究复合结构参数改变对结构磁电特性的影响,并在磁电转换电压系数最大化的前提下对结构进行了优化设计。对于采用等截面基底的复合结构,分析了压电材料长度、基底长度、基底材料机械品质因数以及复合结构整体宽度几个因素,对复合结构发生一阶纵向谐振时的磁电性能的影响;对于采用尖楔形基底的复合结构,分析了压电材料的粘贴位置、压电材料的长度、宽度以及基底长/宽比几个因素,对复合结构发生纵向谐振时的磁电性能的影响。对比两种结构在谐振时产生的磁电转换电压,验证采用尖楔形基底的复合结构聚能效果。并分析了由于弯曲谐振模态的存在,两种复合结构磁电转换电压随激励信号频率变化的曲线都存在多磁电转换电压峰值点的特性。3.制备了采用等截面弹性基底和尖楔形弹性基底的磁电复合结构器件,构建磁电效应实验系统,在实验系统上对器件的磁电电压转换系数进行实测。有限元分析结果与实验结果对比表明,有限元分析可以较准确地预测结构的谐振频率和磁电转换电压的变化趋势,得到的优化结构具有更高的磁电电压转换系数,可以为类似结构的设计和优化提供依据。更多还原

【Abstract】 Magnetoelectric composites can interconvert energies between magnetic field and electric field, and can be applied in magnetic field detection, microwave leak monitoring and electromagnetic field energy conversion. The laminate composites have higher magnetoelectric voltage coefficients than the particle composites. The magnetoelectric composite of three phases by bonding the laminated magnetostrictive and piezoelectric materials onto an elastic substrate has been proposed by our research group. Compared with the two-phase magnetostrictive-piezoelectric laminate composite, it has higher magnetoelectric voltage coefficient at resonance. In this paper, the magnetoelectric performances of two composites are studied by finite element analysis, one with constant section substrate and another with sharp wedge-shaped substrate. The main work is as follows:1. The finite element analysis model of magnetostrictive effect is established in a way analogy to that of piezoelectric effect for the finite element analysis of the magnetoelectric effect of the magnetoelectric composite with elastic substrate. The finite element models of these two kinds of magnetoelectric composites are established by inputting geometric model, selecting element types, meshing solid model, applying loads and applying boundary conditions.2. These two kinds of magnetoelectric composites are analyzed by finite element method. The influences of the composites’parameters’variation on the magnetoelectric characteristics of the composites are studied. The composites are optimized in terms of maximizing the magnetoelectric voltage coefficients. For the magnetoelectric composite with constant section substrate, the influences of the length of the piezoelectric material, the length of the substrate, the mechanical quality factor of the substrate, and the width of the composite on the magnetoelectric characteristics of the composites are studied, at first-order longitudinal resonance. For the magnetoelectric composite with sharp wedge-shaped substrate, the influences of the position, the length and the width of the piezoelectric material, and the bottom width of the substrate on the magnetoelectric characteristics of the composites are studied, at longitudinal resonance. Compared with the constant section substrate composite, the energy-concentrated effect of the sharp wedge-shaped substrate composite is validated. Because of the flexural resonance, these two kinds of composites’magnetoelectric voltages varying with the frequency of the driving signal both have multiple peaks.3. The devices of these two kinds of magnetoelectric composites are prepared. And the magnetoelectric response measure system is established. The magnetoelectric performances of the devices are measured. Compared with the experimental results, finite element analysis can predict the harmonic frequency and the variation of the magnetoelectric voltage of the composite exactly. The optimal composite has higher magnetoelectric voltage coefficient, which is optimized by finite element analysis. The finite element method provides guidance for designing and optimizing the similar composites.更多还原