输电线路覆冰监测拉力传感器性能测试

为实现基于输电线路覆冰的光纤Bragg光栅拉力传感器的性能分析,设计了一个量程为50kN的拉力传感器对其进行校准实验。通过实验中解调仪的中心波长和实验拉力机产生的拉力值进行线性拟合,求出该光纤Bragg光栅传感器的静态性能指标参数。结果表明:光纤传感器的灵敏度为28. 9N/nm,线性度为0. 91%FS,迟滞误差为0. 54%FS,零点漂移小。     

基于光纤传感技术的输电杆塔倾斜传感器研究

针对输电杆塔的监测研究了一种基于光纤布拉格传感技术的倾角传感器,该传感器内固定有一根等强度悬臂梁,在悬臂梁两侧各粘有一个光纤布拉格光栅(FBG),在其自由端挂有一重物。当传感器倾斜时,重物带动等强度自由端重物产生挠度,使传感器的中心波长发生变化,通过监测中心波长来达到监测杆塔倾斜的目的。实验表明:该光纤布拉格光栅倾角传感器的灵敏度为0.317 2nm/°,线性度为1.030%FS,迟滞性误差为0.364%FS,具有零点漂移小的特点。     

专利摘要

200510010505.7埋入公路中的光纤光栅传感器及其封装方法本发明提供的是埋入公路中的光纤光栅传感器及其封装方法。它包括光纤布拉格光栅传感器,在光纤布拉各光栅传感器外有玻璃纤维板封装,光纤布拉格光栅的延长线上套有保护套管。将光纤布拉格光栅的延长线穿入保护套管中,使光纤布拉格光栅的延长线位于保护套管中,然后把光纤布拉格光栅和延长线熔接在一起,最     

适于高温压力管道表面应变监测的光纤光栅应变片技术研究

为监测高温压力管道表面应变的快速变化,在制作耐300℃高温光纤光栅基础上,设计了1种适于高温环境下压力管道表面应变检测的光纤布拉格光栅应变片,该光纤光栅应变片选用3只聚酰亚胺涂覆层光纤布拉格光栅和高温恒弹合金基底,经高温粘接工艺进行封装,适用于压力管道二维表面高温应变检测。采用等强度悬臂梁方法,对封装好的高温光纤光栅应变片进行了高温性能和应变性能实验测试,验证了高温光纤光栅应变片的工作性能,给出了高温管道光纤光栅应变片监测系统的技术方案。     

光纤光栅化学质量分数传感器在矿石加工中的应用

阐述了长周期光纤光栅(LPFG)和布拉格光纤光栅(FBG)化学质量分数传感器的结构与传感原理,分别研究了基于LPFG和FBG的传感器在化学溶液质量分数测量中消除温度敏感对传感影响的机理,并通过实验进行了验证.分析了两种化学质量分数传感器的灵敏度,其中本实验室研制的双布拉格光纤光栅(FBG)化学质量分数传感器通过测量布拉格光栅的双峰偏移间距来实现传感,其灵敏度可达到蔗糖溶液质量分数每1%的变化,反射波长移动0.096 nm.     

基于光纤Bragg光栅的管道压力在线监测

介绍了基于光纤Bragg光栅的管道压力测量方法.液压实验结果表明,沿环向粘贴在管道外壁的光纤Bragg光栅的实验灵敏度为188.1pm/MPa,非线性误差为4.89%Fs;沿轴向粘贴在管道外壁的光纤Bmgg光栅的实验灵敏度为26.7 pm/MPa,非线性误差为6.25%FS.传感器适用于设计压力低于10MPa的中低压管...     

弹性体结构光纤光栅应变传感器的设计与性能研究

为提高光纤光栅传感器的精度和长期使用稳定度,在分析其应变响应机理和研究现状的基础上,设计基于应变弹性体封装的光纤光栅应变传感器,封装材料采用305不锈钢。力学传递原理和Ansys力学分析结果都表明:该传感器能够有效地通过弹性结构将应变传递到光纤光栅上。利用激光切割技术制作不锈钢光纤光栅传感器封装壳体,在-2 000~2 000με的测量范围内,实验测得其应变灵敏度为1.21pm/με、线性度达0.999 6、检测精度不大于1με、稳定度不大于±3με。     

基于FBG传感器的碳纤维复合材料内部热应变监测

将光纤布拉格光栅(Fiber Bragg Grating,简称"FBG")传感器分别埋入单向板和平纹机织层压复合材料中,采用Sm125型光纤光栅解调仪测试两种复合材料在20~100℃温度范围内的内部热应变,分析单向板和平纹机织层压复合材料在仅受温度作用下内部热应变变化特征。结果表明,FBG传感器可以准确测量复合材料内部热应变变化;单向板和平纹机织层压复合材料的内部热应变均随温度升高而增大;织物结构影响复合材料内部热应变,且同一温度点,平纹机织层压复合材料内部热应变较单向板大。     

基于FBG的复合材料内固化过程应力和温度监测

阐述了玻璃纤维增强塑料管道内加热固化系统结构,采用光纤布拉格光栅传感器检测原理,设计了内固化过程应力和温度监测系统,重点解决了光纤光栅的交叉敏感和芯模旋转问题,监测分析了玻璃纤维增强塑料板固化过程的内部应力和温度变化历程,实践证明,该监测系统实时性高,数据检测精确.     

光纤光栅传感器设计及解调仪研发

针对油气井测试监测技术需求与应用,结合现有光纤及光栅传感技术,研制油气井高温高压光纤光栅传感仪。探明飞秒激光刻写光栅的光谱特性差、制备重复率低等问题的内在机制,设计制备温度和压力可以同时测量的光纤光栅传感器件,解决油气井下高温、高压、强腐蚀性等苛刻工况对灵敏度、精度、稳定性造成的影响,为光纤传感器在油气井钻井、完井、测试等领域获得广泛应用奠定基础。通过仪器研制的原始创新,推动油气井油气井测试监测技术的发展,提高石油开采的效率。     

Measurement of low velocity and quasi‐static failure modes in PMMA

An investigation of the low velocity impact and quasi‐static failure of polymethylmethacrylate (PMMA) based on global and local strain measurements was conducted. Local strains were obtained from surface‐mounted fiber Bragg grating (FBG) sensors, and they were combined with global measurements from quasi‐static indentation and low‐velocity impact experiments to obtain detailed maps of how failure evolves. For both loading regimes, the interactions between the host PMMA specimens and the sensors played a crucial role in the evolution of residual strains. A mapping of the strains clearly shows that strains decrease radially, from high values near the point of impact to far‐field values. Sensors located in critical locations had the highest residual strains prior to PMMA fracture. Furthermore, it was determined that strain transfer to the sensor is strongly influenced by the bonding conditions at the specimen's surface. Because of the debonding of the sensor and the frictional effects associated with the bonding agent, compressive residual strains occurred on the rear‐surface. Hence, a detailed understanding of how strain evolves due to sensor–host interactions and catastrophic fracture can be obtained, which can potentially be used to mitigate damage in PMMA for a range of strain rates. POLYM. COMPOS., 28:381–391, 2007. © 2007 Society of Plastics Engineers     

基于真空镀膜技术的薄膜热传感器实验

采用真空蒸发镀膜技术设计制作了以云母为基片的薄膜热传感器,传感器包括一个用于热流测量的热电堆和一个用于温度测量的热电偶。综合测试发现：云母基片薄膜热传感器性能良好。封装后,薄膜热电偶的静态标定拟合直线相关系数均可以达到0.999。薄膜热流计的静态标定拟合直线的相关系数为0.99439,测头系数为8.78886 W/(m²?μV),灵敏度为0.11378 μV/(W/m²)。薄膜热电偶的动态响应时间是0.446 s且具有良好的复现性。随着加载热流的增大,薄膜热流计的动态响应时间变大,阶跃热流值为600 W/m²时响应时间为0.483 s。     

悬臂梁结构光纤光栅电流传感器的优化

针对电力系统对电流测量高精度的要求,设计了一种基于等强度悬臂梁结构的光纤光栅电流传感器。将两根光栅分别粘贴于等腰三角形结构的悬臂梁上下表面,末端永磁体材料振子置于两螺线圈中间。当螺线圈接通电流时,形成的磁场将会引起永磁体振子偏移,进而引起光栅中心波长的变化。采用差分方式建立电流大小与光栅波长变化之间的关系,在提高测量灵敏度的同时消除了温度对测量结果的影响。实验结果表明:在0~5A的范围内,利用光纤光栅波长变化可准确反演待测电流值,与理论计算值相比,误差小于1.2%。     

Assessment of thermoset cure‐induced strains by fiber bragg grating sensor

Composites based on thermosetting resin and reinforcement fibers present generally unwanted residual internal stresses inherent to their elaboration process. In this article, different curing experiments of thermosets (isothermal and anisothermal) were monitored using optical fiber Bragg grating (FBG) sensors and thermocouples, to assess the cure‐induced strains. A thermokinetic model evaluates the degree of conversion of the resin. At the onset of stress transfer to the optical fiber, the degree of conversion ranges between 0.63 and 0.68. During curing, the FBG deforms under chemical shrinkage with an amplitude widely lower than the expected chemical strain, showing that the FBG signal is not directly related to the actual chemical shrinkage. However, once the resin is cured, the FBG sensor provides directly the coefficient of thermal expansion of the resin, as function of temperature and degree of conversion, reached in the different experiments. POLYM. ENG. SCI., 54:1585–1594, 2014. © 2013 Society of Plastics Engineers     

Crack monitoring using multiple smart materials; fiber-optic sensors & piezo sensors

ABSTRACT

This article focuses on health monitoring of structures using multiple smart materials. In this research, two fiber-optic sensors, namely fiber Bragg grating (FBG) and fiber-optic polarimetric sensor (FOPS), are investigated for damage detection in the beam specimen. FBG is used for local strain measurement while FOPS is used for global strain measurement. Both FBG and FOPS show significant changes in the strain due to damages in the specimen. Also, at the center of the specimen, piezoelectric wafer active sensor (PWAS) is attached. The electromechanical admittance (EMA) signature of the specimen beam is recorded by PWAS. The changes in the amplitudes of the peaks obtained at various frequencies in this EMA signature are analyzed, and it is shown that the peak amplitudes respond differently to damages and to change in loading. Thus, multiple smart materials (FBG, FOPS, and PWAS) are used to get improved information on the health of the beam.     

Strain Profile Measurement for Structural Health Monitoring of Woven Carbon-fiber Reinforced Polymer Composite Bonded joints by Fiber Optic Sensing Using an Optical Backscatter Reflectometer

In order to monitor crack initiation and propagation under static and fatigue loading in adhesively bonded joints, strain profile measurement such as backface strain (BFS) is a very efficient technique. In single lap (SL) joints, crack initiation and propagation in the glue line can be monitored by detecting the negative peak of the strain profile. Therefore, the accuracy of the monitoring system greatly depends on detecting the strain profile correctly and accurately. Previously, an array of electrical strain gages as well as fiber Bragg grating (FBG) sensors had been used successfully to capture the profile of BFS of a SL joint by applying sensors on the backface of an adherend, near the overlap zone. In this work, the backface technique is improved by replacing an array of strain sensors by an ordinary optical fiber (without FBG sensors) connected to an optical backscatter reflectometer. The great advantage of this system over the more conventional arrays of FBG is that the entire length of the fiber can be used for sensing strains, and hence it provides a better spatial resolution. The experimental results are compared with finite element analyses, which were further validated by two-dimensional digital image correlation measurements.     

压力传感器在超低温下的校验装置设计与标定

设计了一套在超低温环境下对压力传感器进行测试和标定的校验装置,并且成功地在-253～-163℃、0～2MPa压力范围内对自行研制的超低温压力传感器进行了标定。     

光纤光栅机敏混凝土的研究

结合光纤光栅传感技术的优点,提出了一种新型光纤光栅机敏混凝土原理,并对该原理和特性进行了分析,阐明了实现光纤光栅机敏混凝土原理和系统的关键技术和方法,并通过原理性实验得以验证.光纤光栅机敏混凝土在结构的长期状态监测和损伤诊断方面具有良好的前景.