摘 要

振动检测是表征机械装备健康状态与实现故障诊断的一项关键技术。机械装备通常工作于强电磁等恶劣环境，传统电类振动传感器测量精度易受恶劣环境的影响，还难以满足这种检测需求。光纤光栅（FBG）传感器具有抗电磁干扰、耐腐蚀、无源传感、易于实现分布式测量等优点，近年来已逐步应用于机械装备应变、温度等状态参量的监测。本论文通过发挥和运用光纤光栅强的环境适应性和轴向拉压感知特性，提出了一种基于复合柔性结构的三维FBG振动传感器。主要研究内容是：

（1）阐述了振动检测对机械装备的重要性，总结了多维FBG振动传感器的国内外研究现状，并根据振动信号向FBG应变转换方式的不同，将多维FBG振动传感器分为粘贴型、基于FBG轴向特性和基于FBG横向特性的多维振动传感器。

（2）介绍了光纤光栅传感基本原理，建立了光纤光栅振动传感基本模型，并确定了位移或加速度振动传感器设计时频率比的选取范围，为FBG振动传感器的设计提拱了基本指导模型。

（3）提出了基于空间正交配置的三对弹性体与悬置光纤光栅的三维光纤光栅振动传感器结构模型，推导确定了三维振动与光纤光栅中心波长的数学解析关系；基于三维空间正交布置的三对FBGs中心波长漂移的差分输出，实现了三维振动信号的同步解耦；理论分析了传感器的动静态传感特性，并通过仿真验证了理论模型的正确性。

（4）利用ANSYS平台的优化模块，研究了弹性体和质量块尺寸及其材料对传感器灵敏度的影响规律，确定了弹性体和质量快的最优尺寸以及对应材料的选取准则。仿真结果表明，优化后传感器各方向的灵敏度分别为7.19pm/g、5.95pm/g和6.51pm/g，分别比优化前提高了4.43倍、4.34倍和5.38倍；在频率为20-500Hz范围内，传感器具有良好的动态响应性能，且横向串扰误差小于0.41%。

关键词：光纤光栅；柔性结构；振动传感模型；三维振动测量

Abstract

Vibration measurement is an essential technology to signify the health state and diagnose faults of mechanical equipment. Such equipment is typically working in some harsh environments such strong magnetic field, but traditional electrical vibration sensors are difficult to achieve precise measurement under such harsh environments. Fiber Bragg grating (FBG) sensors possess some inherent advantages such as resistance of electromagnetic interference and corrosion, passive sensing, capability of distributed sensing, etc., which have been gradually applied for the state parameters (such as strain, temperature and so on) measurement of mechanical equipment. In this paper, a three-dimensional FBG vibration sensor based on the composite flexible structures is proposed by utilizing the strong environment adaptability and axial property of FBG. The main work is arranged as follows:

(1) The importance of vibration measurement for mechanical equipment is introduced, and the researches about multi-dimensional FBG vibration sensor at home and abroad is reviewed. Based on the difference of vibration-strain transferred way to FBG, three types of FBG-based multi-dimensional vibration sensors have been classified, which are pasted FBG-based, axial property of FBG-based and transverse property of FBG-based, respectively.

(2) The basic principles of FBG are introduced, and FBG-based vibration model are established, which can be a guidance for the design of FBG-based vibration sensors.

(3) A three-dimensional FBG vibration sensor based on three pairs of orthogonal elastomers and suspended FBGs is proposed, the relationship between the three-dimensional vibration and the central wavelength of FBGs is derived, and the synchronous decoupling of three-dimensional vibration signal is realized through the difference method of three pairs of orthogonally arranged FBGs’ center wavelength shift. Besides, the theoretical model of the dynamic and static characteristics of the proposed sensor is analyzed, which is also verified by simulation.

(4) The relationship of the size of elastomer and mass block and the sensor sensitivity liis analyzed by utilizing the optimization module of ANSYS. And the material of the sensor is determined, by comparing the sensitivity of the sensors made of different materials. The simulation results show that the sensitivity the optimized sensor along x-, y- and z-direction are 7.19pm/g, 5.95pm/g and 6.51pm/g, respectively, which are 4.43 times, 4.34 times and 5.38 times higher than the initial one, respectively. Besides, the sensor possesses good dynamic response in the range of 20-500Hz, and its cross-interference is less than 0.41%.

Key words：Fiber Bragg grating; Flexural structure; Vibration sensing model; Three-dimensional vibration measurement

目 录

第1章 绪论 1

1.1 研究背景与意义 1

1.2 国内外研究现状 1

1.2.1 粘贴型FBG多维振动传感器研究现状 2

1.2.2 基于FBG轴向特性的多维振动传感器研究现状 3

1.2.3 基于FBG横向特性的多维振动传感器研究现状 5

1.3 本论文主要工作 6

第2章 光纤光栅振动传感理论模型 7

2.1 FBG传感基本原理 7

2.2 光纤光栅振动传感模型 8

2.3 本章小结 10

第3章 三维光纤光栅振动传感器设计 11

3.1 设计思路 11

3.2 三维振动传感器理论模型 11

3.2.1 传感器灵敏度分析 12

3.2.2 传感器动态特性分析 14

3.3 传感器静态特性仿真分析 15

3.4 传感器动态特性仿真分析 19

3.5 本章小结 20

第4章 三维光纤光栅振动传感器灵敏度优化 21

4.1 基于ANSYS优化分析的传感器灵敏度优化 21

4.1.1 ANSYS优化设计基本概念 21

4.1.2 弹性体尺寸对灵敏度的影响 21

4.1.3 质量块对灵敏度的影响 24

4.1.4 传感器优化前后尺寸对比 24

4.2 传感器材料对灵敏度的影响 25

4.2.1 弹性体材料对灵敏度的影响 25

4.2.2 质量块材料对灵敏度的影响 26

4.3 传感器有限元仿真分析 26

4.4 传感器封装结构设计 28

4.5 本章小结 29

第5章 总结与展望 30

5.1 总结 30

5.2 展望 31

参考文献 32

本科学习期间的主要成果 34

致 谢 35

第1章 绪论

1.1 研究背景与意义

随着现代机械制造技术大型化、集成化、高速化和自动化的不断发展，许多大型机械装备常在高温、强电磁干扰等多场耦合的工况下运行，其运行状态存在多变性和耦合性，这些变化对机械装备状态监测提出了更高的要求^[1]。机械系统中重大机械装备发生故障，不仅会造成巨大的经济损失，而且会危及人身安全。因此，重大机械装备运行过程中的状态监测一直是国内外工程技术领域的一个热点话题，是保障机械装备的安全性和可靠性，减少国民经济损失的关键。

机械装备的损坏或故障等状态信息通常隐含于振动信号中，通过对振动信号进行监测即可掌握机械装备的实时运行状态信息，进而能够在设备发生故障之前预警，防止突发事故。因此振动信号是反映机械装备状态的关键物理量，在机械装备实时状态监测和故障诊断中的作用十分显著。