层状磁电装置的性能优化及构型设计

发布时间：2017-12-28 04:17

本文关键词：层状磁电装置的性能优化及构型设计　出处：《兰州大学》2016年硕士论文　论文类型：学位论文

【摘要】：磁电效应是介质受磁场作用产生电极化,或受电场作用产生磁极化的物理现象。近年来,由磁致伸缩材料和压电材料组成的层状复合磁电效应装置因为极其显著的磁电特性,逐渐引起了人们的注意,并被不断应用于智能电子器件领域。目前,该领域的研究主要集中在提高装置的磁电转换效率。现已表明,影响转换效率的因素主要包括:材料参数、外部磁场大小和驱动磁场频率,然而鲜有研究从理论角度解释磁场方向和外部环境温度对磁电转换效率的影响。为此,本论文从磁场角度、环境温度和结构构型入手,建立了磁电效应多场耦合模型,优化了层状磁电装置性能,同时提出了U型磁电装置。具体内容包括:首先,本论文基于弹性力学法,建立了的考虑磁场角度的层状磁电效应模型,并对不同磁场角度下的磁电效应进行了理论预测,其预测结果与现有实验吻合较好。结果表明,磁场角度对磁电转化效率影响显著。当交流磁场沿层状磁电装置长度方向时,存在一个最优的直流磁场角度可以使得装置获得最大的磁电响应,直流磁场值越大,最优角度越大。当交流磁场置于宽度方向时,无论直流磁场为何值,最优的磁场角度总是在0o。但与前者不同,后者获得最大磁电系数对应的最优磁场却随着磁场角度的增加而逐渐减小。同时本文也发现,装置在共振频率的磁电转换效率大致为低频下的100倍,且转换效率随磁场角度的变化规律保持不变。本论文结果表明,在实际生产设计中,最好的磁电器件设计方案是直流磁场保持与交流磁场共线。这样既可以获得最大的磁电系数,又不至于施加一个过大的直流磁场。其次,本论文基于等效电路法,建立了考虑环境温度影响的功能梯度型层状自偏磁电效应模型。利用该模型得到的压磁系数随直流磁场的变化规律与现有的实验结果保持一致。其预测结果显示,在较低的预应力作用下(大约?50MPa),磁电转换效率随着温度升高而减弱,而在较大的预应力作用下,则会随着温度升高而增强,但整体而言,较低的工作温度和较小的预应力更有利于功能梯度型自偏磁电装置的磁电转换。最后,本论文从结构构型设计角度出发,提出了U型磁电装置,并首次建立了该构型的理论模型。结果表明,磁致伸缩材料越长,压电材料越短,越有利于U型装置的磁电效应。同时,实验结果显示,当共振频率为91kHz时,装置获得1.3V/cmOe的最大磁电转换效率,而在低频磁电系数也可达到0.225V/cmOe。总之,本论文从磁场角度、环境温度和结构构型入手,完善和发展了磁电效应多场耦合模型,并提出了U型磁电装置。本文的理论分析、数值仿真以及实验工作丰富和发展了多场耦合磁电效应理论,同时也对层状磁电装置的技术改进和实际应用具有一定的指导意义。
[Abstract]:The magnetoelectric effect is the physical phenomenon that the medium is polarized by the action of the magnetic field or by the action of the electric field. In recent years, the magnetostrictive material composed of magnetostrictive materials and piezoelectric materials has attracted much attention due to its remarkable magnetoelectric properties, and has been applied in the field of intelligent electronic devices. At present, the research in this field is mainly focused on improving the efficiency of the magnetoelectric conversion of the device. It has been shown that the factors that affect the conversion efficiency include material parameters, external magnetic field size and driving magnetic field frequency. However, few studies have explained theoretically the influence of magnetic field direction and external ambient temperature on the efficiency of magnetoelectric conversion. For this reason, starting from magnetic field angle, environment temperature and structure configuration, this paper establishes a multi field coupling model of magnetoelectric effect, optimizes the performance of the layered magnetoelectric device, and puts forward the U type magnetoelectric device. The main contents are as follows: first, based on the elastic mechanics method, a layered magnetoelectric effect model considering magnetic field angle is established, and the magnetoelectric effect under different magnetic field angles is theoretically predicted. The prediction results are in good agreement with the existing experiments. The results show that the magnetic field angle has a significant influence on the efficiency of the magnetoelectric conversion. When the AC magnetic field is along the length of the layered magnetoelectric device, there is an optimal DC magnetic field angle, which can make the device get the largest magnetoelectric response. The larger the DC magnetic field is, the larger the optimal angle is. When the AC magnetic field is placed in the direction of width, the optimal angle of magnetic field is always at 0o regardless of the value of the DC magnetic field. But different from the former, the optimal magnetic field corresponding to the maximum magnetoelectric coefficient decreases with the increase of the angle of the magnetic field. At the same time, it is also found that the efficiency of magnetoelectric conversion at resonance frequency is about 100 times lower than that at low frequency, and the conversion efficiency keeps unchanged with the variation of magnetic field angle. The results of this paper show that in the actual production design, the best design of the magnetoelectric device is the co - line between the DC magnetic field and the AC magnetic field. In this way, the maximum magnetoelectric coefficient can be obtained, and a large DC magnetic field is not applied. Secondly, based on the equivalent circuit method, a functionally graded self biased magnetoelectric effect model with the influence of ambient temperature is established. The variation of the piezomagnetic coefficient with the DC magnetic field is consistent with the existing experimental results. The forecast results show that in the prestressed low (about 50MPa?), magnetoelectric conversion efficiency decreases with the increase of temperature, and the prestressing force is large, it will be enhanced with the increase of temperature, but on the whole, lower working temperature and smaller pre stress is more conducive to the function gradient type magnetoelectric conversion partial electric device. Finally, from the perspective of structural configuration design, the U magnetoelectric device is proposed, and the theoretical model of the configuration is established for the first time. The results show that the longer the magnetostrictive material is, the shorter the piezoelectric material is, the more it is beneficial to the magnetoelectric effect of the U type device. Meanwhile, the experimental results show that when the resonant frequency is 91kHz, the maximum magnetoelectric conversion efficiency of 1.3V/cmOe is achieved, while the low frequency magnetoelectric coefficient can also reach 0.225V/cmOe. In a word, starting with the magnetic field angle, ambient temperature and structure configuration, the multi field coupling model of the magnetoelectric effect is perfected and developed, and the U type magnetoelectric device is put forward. The theoretical analysis, numerical simulation and experimental work in this paper enrich and develop the theory of multi field coupled magnetoelectric effect, and also have some guiding significance for the improvement and practical application of the layered magnetoelectric device.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB33

【相似文献】