基于三角滤波器的光纤光栅交叉敏感技术研究

光纤光栅传感器对温度、应变都具有敏感性。在作为应变传感器使用时,为了保证测量精度,利用FFP(fiber Fabry-Pérot)干涉仪反射谱的上升沿和下降沿设计了三角陷波器,实现了光纤光栅应变的单参数测量,有效地消除了温度的交叉敏感影响。该方法具有原理简单、易于实现等优点,在-20~70℃温度变化范围内,应变误差为±4×10-6,能够满足桥梁测量中对该参数的要求。     

光纤光栅传感技术在桥梁施工监控中的应用

为了满足桥梁顶推法施工监控的复杂要求,分析了光纤光栅传感器的结构和原理;研究了应变和温度交叉敏感以及波长解调等光纤Bragg光栅(FBG)传感技术应用中的关键问题.根据对桥墩受力变形的分析,结合实例设计了传感器参数.将虚拟仪器与FBG传感器相结合,可以利用虚拟仪器技术在信号采集、分析、存储和传输等方面的优势,实现光纤光栅解调与施工监控于一体,保证了施工安全和桥梁质量.     

基于LabVIEW的FBG温度传感器数据采集系统设计

针对光纤B ragg光栅(FBG)温度传感器实时监测过程中,对数据采集和处理的快速、准确的要求,提出了一种基于虚拟仪器技术的实时数据采集处理系统设计方案。该方案在首先考虑FBG温度传感器原理的基础上设计了数据采集处理系统,应用虚拟仪器软件LabVIEW语言编写程序,实现了对数据采集系统的控制与处理。对FBG温度传感器的实验测试表明:所设计的系统能够满足FBG传感器实时数据采集和处理的要求。     

N元光纤光栅传感器阵列解调信号的最低可见度分析

研究了非平衡光纤Mach-Zehnder干涉仪解调N元光纤光栅传感器阵列时的偏振衰落问题．运用邦加球和光纤偏振光传输理论，利用简化模型，通过详细的理论分析，得到优化控制下阵列传感信号最低可见度的下限表达式，并通过计算机仿真，验证了结果的正确性，并详细分析了仿真实验的结果．     

Thermal Properties Measurement of Micro-electromechanical System Sensors by Digital Moire Method

Abstract:  The thermal properties of a micro-electromechanical system sensor were analysed by a novel digital moiré method. A double-layer micro-cantilever sensor (60  μ m long, 10  μ m width and 2  μ m thick) was prepared by focused ion beam milling. A grating with frequency of 5000 lines mm⁻¹ was etched on the cantilever. The sensor was placed into a scanning electron microscope system with a high temperature device. The observation and recording of the thermal deformation of the grating were realised in real-time as the temperature rose from room temperature to 300 °C at intervals of 50 °C. Digital moiré was generated by interference of the deformed grating and a digital virtual grating. The thermal properties including strain distribution of the sensor and the linear expansion coefficient of polysilicon were accurately measured by the phase-shifted moiré patterns.     

Development of smart composite structures with small-diameter fiber Bragg grating sensors for damage detection: Quantitative evaluation of delamination length in CFRP laminates using Lamb wave sensing

The authors and Hitachi Cable, Ltd. have recently developed small-diameter optical fiber and its fiber Bragg grating (FBG) sensor for embedment inside a lamina of composite laminates without strength reduction. The outside diameters of the cladding and polyimide coating are 40 and 52 μm, respectively. First, a brief summary is presented for applications of small-diameter FBG sensors to damage monitoring in composite structures. Then, we propose a new damage detection system for quantitative evaluation of delamination length in CFRP laminates using Lamb wave sensing. In this system, a piezo-ceramic actuator generates Lamb waves in a CFRP laminate. After the waves propagate in the laminate, transmitted waves are received by an FBG sensor attached on or embedded in the laminate using a newly developed high-speed optical wavelength interrogation system. This system was applied to detect interlaminar delamination in CFRP cross-ply laminates. When the Lamb waves passed through the delamination, the amplitude decreased and a new wave mode appeared. These phenomena could be well simulated using a finite element analysis. From the changes in the amplitude ratio and the arrival time of the new mode depending on the delamination length, it was found that this system could evaluate the delamination length quantitatively. Furthermore, small-diameter FBG sensors were embedded in a double-lap type coupon specimen, and the debonding progress could be evaluated using the wavelet transform.     

一种高分辨力的光纤光栅悬臂梁动态解调技术

介绍了一种基于悬臂梁的匹配光栅测量和解调方案,在外界加速度作用下,一个光纤光栅受压,另一个光纤光栅受拉,使波长调谐的灵敏度增加了1倍。实验证明了该方法寓解调和温度补偿为一体的优越性,本解调方案的波长移动分辨力为0. 01pm,可实现高分辨力加速度测量。     

提高容栅位移传感器精度的有效方法

为解决环境温度变化、尺体导轨加工误差以及边缘效应等因素对容栅位移传感器测量精度的影响,提出了三极板结构、周期比较测量以及分段采用正余弦极板分段数据处理的方案。三极板结构中动极板仅起屏蔽作用,可以降低对尺体导轨加工精度的要求;周期比较测量在提高系统温度稳定性的同时,由于采用了全数字电路的实现方式能有效降低专用集成电路的设计、制作成本;交替使用正余弦极板的读数避开边缘效应的影响。理论分析和实验结果证明了该方案的可行性。     

基于光纤光栅温度传感技术的面板坝渗漏监测系统

对某些水库渗漏位置的检查一般采用放空水库的办法来进行,这对于严重缺水的工农业生产来说,是一种极大的浪费,采用的基于光纤光栅温度传感技术的面板坝渗漏监测系统对混凝土面板堆石坝面板渗漏能实时、在线、长期可靠监测。用于传感和信号传输的光缆可以埋置于面板底部或中性面上以及其他需要的位置,不会因机械施工而损伤,具有施工干扰小、抗电磁干扰等特点,试验表明:系统可有效检测大坝渗漏情况。     

光电二维自动检测系统的研究

本论文从下面几个方面对光电二维自动检测系统进行了全面的论述：系统的整体结构，系统的硬件设计和系统的软件设计。同时，我们还讨论了可编程器件CPLD的编程应用来简化电路的设计。上位机系统软件采用LABVIEW图形化编程环境，通过交互式图形化前面板来控制系统，并显示结果。