基于磁致伸缩复合材料的光纤激光磁场传感器研究

发布时间：2018-11-09 12:38

【摘要】：近年来,由于光纤磁场传感器的诸多性能优势,如抗电磁干扰能力强,重量轻,体积小以及带宽大等等,在研究中受到了越来越多的关注。一些物理现象,如法拉第效应、磁力等等,都可以用于制作光纤磁场传感器,这其中,最流行的莫过于基于磁致伸缩材料的光纤磁场传感器的研究。然而,磁致伸缩材料非常脆弱,在高频工作状态下会因低电阻率而产生较强的涡流效应。因此,本课题提出了一种磁致伸缩复合材料,以求性能上的提高。在本文中,我们设计了一种新型的微型光纤磁场传感器,通过将DBR光纤激光器嵌入环氧树脂与Terfenol-D粉末混合的磁致伸缩复合材料中而制得。DBR光纤光栅激光器是利用一个193nm准分子激光器,在掺铒光纤上分别刻写长度为6.5mm和5.5mm的光栅,光栅间距为5mm而制得。磁致伸缩复合材料是按照Terfenol-D粒子、E44环氧树脂和650聚酰胺固化剂体积比为1:10:10混合制备而成。当施加横向磁场时,磁场诱导磁致伸缩复合材料发生形变。磁场传感器的机械结构将形变转换成横向应力施加于嵌入的DBR光纤激光器上。然后,激光的双折射发生改变,最终表现为拍频信号的变化。通过鉴别拍频信号频率的变化,来测量施加的磁场强度。经测量,本文提出的磁场传感器的灵敏度可达10.5Hz/μT,磁场测量范围高达约0.3T。本论文的主要内容如下:首先,我们研究双偏振光纤激光器的制备。利用相位掩膜法及193nm准分子激光器,在掺饵光纤上直接刻写与模板波长相匹配的光纤光栅对,进而研制出了具有两个正交偏振态的单纵模DBR光纤光栅激光器,并通过退火处理提升了DBR光纤激光器的性能。其次,利用Terfenol-D粉末,环氧树脂E44及其固化剂,对磁致伸缩复合材料进行了制备,建立了树脂基磁致伸缩复合材料的受力模型,并进行了公式推导。对制备过程中的工艺与注意事项进行了简短的讨论。再次,实现了基于磁致伸缩复合材料的DBR光纤磁场传感器,根据光纤中的双折射效应,推导了光纤激光器的拍频漂移与待测磁场之间的关系,实验上实现了对磁场的测量,验证了相关的理论的准确性及实验模型的有效性。最后,对整篇论文进行了简要的总结与回顾,对基于磁致伸缩复合材料的光纤磁场传感器的应用领域与前景进行了展望。
[Abstract]:In recent years, more and more attention has been paid to the optical fiber magnetic field sensor due to its many performance advantages, such as strong anti-electromagnetic interference ability, light weight, small volume and large bandwidth. Some physical phenomena, such as Faraday effect, magnetic force and so on, can be used to fabricate optical fiber magnetic field sensors, among which, the most popular one is the study of optical fiber magnetic field sensors based on magnetostrictive materials. However, the magnetostrictive materials are very fragile and have strong eddy current effects due to low resistivity in high frequency working conditions. Therefore, a magnetostrictive composite is proposed to improve its properties. In this paper, we design a new kind of micro optical fiber magnetic field sensor. The DBR fiber laser is fabricated by embedding the DBR fiber laser into a magnetostrictive composite material mixed with epoxy resin and Terfenol-D powder. The DBR fiber grating laser is a 193nm excimer laser. The grating with length of 6.5mm and 5.5mm is written on erbium-doped fiber, and the grating spacing is 5mm. The magnetostrictive composites were prepared according to 1:10:10 volume ratio of Terfenol-D particles, E44 epoxy resin and 650 polyamide curing agent. When the transverse magnetic field is applied, the magnetic field induces the deformation of magnetostrictive composites. The mechanical structure of the magnetic field sensor converts the deformation to transverse stress applied to the embedded DBR fiber laser. Then, the birefringence of the laser changes, and finally the beat signal changes. The applied magnetic field intensity is measured by discriminating the frequency variation of the beat signal. The sensitivity of the proposed magnetic field sensor is as high as 10.5Hz/ 渭 T, and the magnetic field measurement range is about 0.3 T. The main contents of this thesis are as follows: firstly, we study the fabrication of dual polarization fiber laser. Using phase mask method and 193nm excimer laser, a pair of fiber Bragg gratings matching the template wavelength is written directly on the decoy fiber, and a single longitudinal mode DBR fiber grating laser with two orthogonal polarization states is developed. The performance of DBR fiber laser is improved by annealing. Secondly, using Terfenol-D powder, epoxy resin E44 and its curing agent, the magnetostrictive composite was prepared, the mechanical model of the resin matrix magnetostrictive composite was established, and the formula was deduced. The preparation process and points for attention were briefly discussed. Thirdly, the DBR fiber magnetic field sensor based on magnetostrictive composite material is realized. According to the birefringence effect in the fiber, the relationship between the beat frequency drift of fiber laser and the magnetic field to be measured is deduced, and the magnetic field is measured experimentally. The accuracy of the related theory and the validity of the experimental model are verified. Finally, the whole paper is briefly summarized and reviewed, and the application field and prospect of optical fiber magnetic field sensor based on magnetostrictive composite materials are prospected.
【学位授予单位】：暨南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33;TP212

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