光纤激光非双盲声隐身传感技术研究

With the rapid development of science and technology, the accuracy of the detection of acoustic field is required much and much higher. Non destructive acoustic field measurement is a difficult and urgent problem in the field of acoustic detection. Acoustic metamaterials can arbitrarily control the acoustic field, which provides a possible way to the nondestructive detection of acoustic filed. Optical fiber acoustic sensors attract extensive attention worldwide in the acoustic sensing field due to their high sensitivity, small volume, and being placed inside the body and easy networking. This project proposed the acoustic stealth sensing technology based on sound metamaterials and fiber lasers, the research contents include: Firstly, we will study and optimize the structure of the acoustic metamaterials in detail theoretically by using finite element method, and we will study the modulation characteristics of acoustic metamaterials on the sound field to achieve the acoustic stealth for the embedded object. Secondly, we will make fiber laser acoustic sensors with high sensitivity and narrow line-width and develop the acoustic sensing signal demodulation system with high precision based on passive homodyne phase detection technology. Thirdly, we will develop the experiment on the fiber laser acoustic stealth sensing based on acoustic metamaterials and measure the sound field distribution inside the material by fiber laser sensors. The biggest bright spot of this project is that we can not only realize the acoustic stealth for the embedded element by the acoustic metamaterials, but also detect the external sound field information by the embedded fiber lasers to achieve anti-detection for the external objects, which realizes non-double blind acoustic stealth sensing.

随着科技的飞速发展，人们对声场探测的精确度要求越来越高，非破坏性声场测量技术是声检测领域的难点和亟待解决的问题。声学超材料因其能对声场进行任意调控，为非破坏声场检测提供了可能的途径。光纤声传感器由于灵敏度高、体积小、能植入材料内部并易于组网等众多突出优点，在声检测领域受到了世界各国的广泛关注。本项目提出基于声学超材料的光纤激光非双盲声隐身传感技术，具体研究内容包括：采用有限元法对声学超常材料的结构进行理论仿真和优化，通过研究其对声场的调控特性来实现声隐身功能。研制高灵敏度、超窄线宽的光纤激光声传感器，用于声场无损检测。开展光纤激光声隐身传感实验研究，验证声学超材料内部放置物体的声隐身效果。该项目的创新点是：一方面利用声学超常材料对声场调控特性，可实现隐身物对外界的声隐身；另一方面利用光纤激光声传感器对外部声场的无损检测，可实现对外界的“反潜”，从而可以实现非双盲声隐身传感。

光纤激光传感器因其具有超窄的带宽、超高的灵敏度和信噪比，在水声传感、声麦克、超声检测以及加速度测量等领域得到了广泛的应用。声学超材料因为具有自然界常规材料所不具备的很多奇异特性，近些年被人们广泛研究。本项目在国家青年科学基金项目的资助下，完成了基于声学超常材料的光纤激光非双盲省隐身传感技术研究工作，利用声学超材料对声波的调制特性，将目标物放置于超材料内部实现对外部环境的“声隐身”，利用内部埋置的光纤声传感器探测外部的声场，从而实现了“反潜”。在理论上设计了适用任意尺寸隐身目标物的声学超材料结构，根据理论仿真优化结果，制作了两种具有声隐身功能和内部声场增强效果的声学超材料。研制了高精度、窄线宽的光纤激光声传感器以及信号解调装置，并将光纤激光声传感器埋置于声学超材料的内部，开展了水下声隐身传感验证性实验。利用BK声学传感器测试了声学超材料的入射声场，利用激光声学传感器测试了46.55kHz和50.7kHz的超声信号，实验表明声传感器具有良好的声学响应。研究了光纤多纵模激光器的传感特性，采用波分-频分混合复用技术，搭建了大规模光纤激光器传感网络，该系统理论上可以复用的传感器个数最多可达725个。研究了影响系统传感单元复用数目的主要因素，包括传感测量范围、泵浦光源的功率、系统中光纤器件的功率限制等。实验搭建了16路光纤激光传感阵列系统，进行了温度应变传感应用研究。研制了偏振型光纤激光传感技术，发展了偏振型光纤激光器温度和应变同时测量技术以及光纤双折侧测量技术。这种大规模的光纤激光传感阵列技术，在结构健康监测、水声测量、航空航天等领域具有很好的应用潜力。本项目共发表学术论文11篇，其中SCI论文7篇，出版学术著作1本，授权发明专利一项，申请专利一项，获得黑龙江省科技技术发明二等奖一项。在项目执行期间，培养博士后1名，博士研究生2人，硕士研究生3人。