考虑超磁致伸缩材料非均匀性的大功率电声换能器阻抗特性

The Impedance Characteristics of High Power Electroacoustic Transducer Considering the Inhomogeneity of Giant Magnetostrictive Material

为了辐射更高的声功率,大功率超磁致伸缩电声换能器常采用多根超磁致伸缩棒材组合的结构,从而辐射更高声功率。现有的阻抗分析方式一般将超磁致伸缩棒材视作均匀一致的个体进行计算,然而该材料所采用的定向凝固制备方法存在固有缺陷,导致材料性能一致性不高,因此将棒材性能均匀化处理的阻抗分析并不准确。该文首先利用有限元仿真展示四根棒材参数互异所带来的阻抗影响。在使用分布参数法进行阻抗分析的基础上,进一步考虑每个棒材不同位置参数的差异。然后将棒材按单位长度进行微分,探究棒材不同位置参数互异带来的影响,以相同参数所占微元进行积分求和,进而分析得到换能器整体的阻抗。通过与传统集总参数模型和实验数据的拟合效果进行对比,可知该文所提出阻抗分析方法更准确,对换能器的设计有重要的指导意义。

High-power giant magnetostrictive electroacoustic transducers usually adopt a structure composed of multiple giant magnetostrictive rods to radiate higher acoustic power.The current impedance analysis methods generally treat giant magnetostrictive bars as uniform individuals for calculation.However,the directional solidification method used in the preparation of the material has inherent defects,resulting in the uneven properties.Therefore,the traditional impedance analysis method is inaccurate.In this paper,the finite element simulation is used to demonstrate the impedance effect caused by parametric differences in four bars.Using the distributed parameter method,the difference of parameters in different positions is further considered.Then,the bars are differentiated by unit length,and the integral sum is carried out with the micro-elements occupied by the same parameters,and then the overall impedance of the transducer is analyzed.By comparing with the traditional lumped parameter model and experimental data,the impedance analysis method proposed in this paper is more accurate and has great significance for guiding the design of the transducer.