Fiber-Optic Polarization Pressure Sensor

The highly sensitive polarization pressure sensor is based on single-mode fiber-optic waveguides. The measured sensitivity has been found experimentally to be 13·10_–2 dB·Pa_–1·m_–1. A /4 phase plate was used as an optical decoupler in the sensor.     

Wavelength Detection of Coherence-Multiplexed Fiber-Optic Sensors Based on Long-Period Grating Pairs

Multiplexed fiber-optic sensors based on long-period grating pairs (LPGPs) are presented. With a low-coherence reflectometry, the spectral responses of the specially configured LPGP sensors are precisely quantified from the corresponding sub-reflectograms through a fast Fourier transformation (FFT). By monitoring the wavelength shift of the LPGP sensors, temperature is measured experimentally, and good performance is obtained     

智能化光纤压力传感器

介绍了一种根据光纤弯曲损耗原理，以中空螺旋形光纤环作为压力传感元件，用８０９８单片机进行控制和数据处理的智能化光纤压力传感器。其测压范围可通过选用不同刚度的弹性元件加以扩大或缩小，测压准确度为０．５％，重复性、非线性误差均小于０．５％。     

一种新型光纤电流传感器的设计

本文提出了一种新型的高压电流光纤传感器 ,该系统由具有相位压缩原理的Sagnac干涉仪光路构成 ,与通常的干涉仪相比该系统的动态测量范围扩大数百倍 ,而且系统不受外界缓变量的影响 ,系统采用相位切换技术使干涉仪保持在正交干涉状态     

Multiplexed Fiber-Optic Pressure and Temperature Sensor System for Down-Hole Measurement

A fiber Fabry–Perot (F-P) interferometer and a fiber Bragg grating (FBG) based pressure and temperature multiplexing sensor system is presented. This system is designed for high-temperature oil well down-hole permanent monitoring of pressure and temperature. Connecting a FBG temperature sensor and a F-P pressure sensor in series in the sensor head, the sensor system combines the advantages of simple structure of FBG for temperature sensing and high accuracy and low-temperature cross-sensitivity of F-P pressure sensor. Experimental results showed that the temperature measurement accuracy of 0.5$;^{circ}$C and the long-term drift of the air gap of the F-P pressure sensor at 300$;^{circ}$C is less than 0.1% within 300 h time span. This indicates that a long-term pressure measured accuracy of 0.03 MPa has been achieved in pressure gauge range of 0–30 MPa and in temperature variation range between 18 $;^{circ}$C to 300 $;^{circ}$C.      

A Fiber-Optic pH Sensor for Microbioreactors

Technical Physics Letters - A fiber-optic sensor for microbioreactors has been developed and manufactured that records pH changes in the range from 6.5 to 9 with an accuracy of ±0.2 for small...     

基于FBG温度解耦的光纤法布里-珀罗 高温压力传感器

本文提出了一种基于光纤布拉格光栅(FBG)温度解耦方法的光纤法珀(FP)压力传感器,该传感器采用低温共烧陶瓷(LTCC)技术实现批量化制作.通过在膜片式压力传感器的基础上集成光纤布拉格光栅(FBG),实现温度、压力双参数测量;提出温度解耦方法,对传感器进行温度补偿及压力测量结果的修正.实验结果表明,在20～300℃的温度范围内, FBG温度传感器的灵敏度为0.012 nm/℃,在160 kPa的压力范围内,压力测量灵敏度约为0.1μm/kPa, 3次重复实验的重复性误差和非线性误差分别约为5.6%和1.3%,温度系数为0.018μm/℃,压力灵敏度随温度变化为0.283 nm/(kPa·℃),同时,采用温度解耦方法,得到压力计算值与真实值最大偏差小于2.5 kPa.     

A Recirculation Fiber-Optic Temperature Sensor

Methods of increasing the accuracy of measurements made with recirculation fiber-optic temperature sensors are considered. It is shown that such data-measuring systems, while possessing all the advantages of amplitude sensors (simplicity, reliability, cheapness, etc.), have high sensitivity and, as regards their metrological characteristics, at the present time can be as good as the most accurate interferometric-type phase fiber-optic sensors.     

新型光纤压力传感器

研究了一种新型的光纤压力传感器,并基于理论模型作了相应的优化设计,该传感器由光纤环和Ｃ形弹簧管复合而成、并配有完善的处理电路及微机测控系统,实用性强。     

一种可同时测量温度和压力的新型SAW传感器

针对汽车轮胎压力监测系统（TPMS）的典型应用,提出了一种基于声表面波（SAW）的新型传感器.这用SAW延迟线理论,温度和压力对于传感器的影响能够通过射频回波信号的变化反映出来.通过在数据处理中引入权重因子,实现对于温度和压力的准确测量.在一定压力（0-200 kPa）和温度（20-100℃）范围内的测试结果表明,该传感器能够同时准确测量温度和压力.SAW传感器对温度的测量精度可以达到0.05℃,对压力的测量精度可以达到7.2 kPa.在对于可靠性和耐久性具有特殊要求的汽车轮胎压力监测等领域,该传感器简单的结构和无线无源的测量方式,进一步提高了其实用性和推广价值.     

A Novel RFID-Based Strain Sensor for Wireless Structural Health Monitoring

Conventional tools for deformation measurement are widely used for structural health monitoring—i.e. strain gauges and fiber optic sensors—due to their relative low cost and efficiency. However, these techniques still present some drawbacks particularly in limited access locations, since their usage requires some sort of cabling or battery-driven electronics. Thus, in a few situations there may be room for new technologies for deformation monitoring of structures. One of the options are passive radio frequency identification (RFID)-based sensors. In synthesis, like conventional methods, these sensors are attached to the surface a test-piece, but are then remotely interrogated and powered by a transmitter. The solidarity of the sensor to the underlying material means that the detected signal is modified in a way that can be correlated to sample strain in a given direction. This paper encompasses the project of a wireless deformation sensor based on an inverted-F antenna focusing on its miniaturization and performance optimization. For this purpose, such an antenna was designed with the help of finite element modelling tools for operation on a 2.0 mm-thick aluminium sheet, and then experimentally validated through static loading tests. Finally, even though sensors of this kind are still in early developments, results show that RFID sensors represents a promising method for remote deformation assessment in components.     

Fiber-Optic Sensor for Web Velocity Measurement

The design and development of a new fiber-optic sensor for measuring the velocity of a continuous material (also called a web) in material processing systems is described. The development of the proposed sensor is based on the dual beam laser Doppler velocimetry technique and the unique properties of different types of optical fibers. The developed sensor is capable of measuring the true web transport velocity as opposed to the existing methods which infer web transport velocity based on the roller angular speed. Since the sensor design utilizes fibers, signal processing can be performed away from the measurement area, and as a result the sensor can be used in harsh environments within the web processing line. The proposed sensor has been constructed and experiments have been conducted on an experimental web platform. The performance of the sensor is evaluated for a range of web velocities and different web materials. Sensor design, its construction, and a representative sample of the results are presented and discussed.     

Real-Time Structural Health Monitoring Using a Novel Fiber-Optic Accelerometer System

This paper presents a novel fiber-optic accelerometer system to monitor civil engineering structures in real time and a successful application of the novel sensor system for damage detection of the concrete slab structure. This sensor system integrates the Moireacute fringe phenomenon with fiber optics to achieve accurate and reliable measurements. A signal processing unit implements unique algorithms to further enhance the resolution and increase the dynamic bandwidth of the sensors. The sensor system is immune to electromagnetic (EM) interference, making it suitable for difficult applications in such environments involving strong EM fields, electrical spark-induced explosion risks, and cabling problems, prohibiting the use of conventional electromagnetic accelerometers. Especially, this paper presents a unique real-time signal processing algorithm and applications to real-time damage assessment, demonstrating the uniquely high performance of the Moireacute fringe fiber-optic sensor system     

光纤光栅传感器在CFRP冲击载荷监测中的应用研究

提出了一种用光纤光栅传感器监测CFRP结构冲击载荷的方法,构建了冲击监测系统。将FBG传感器粘贴于CFRP试件表面构成传感网络,针对不同冲击点,同一传感器监测的冲击响应信号进行分析,CFRP试件的一阶、二阶谐振频率为53 Hz、100 Hz,不同谐振频率对应的幅值随冲击点的改变而不同。冲击CFRP试件,对FBG传感网络感知的冲击响应信号进行小波包分解,获得各传感器的小波包能量谱图。结果表明传感器信号的第6阶小波包能量变化明显,能量大小与冲击点和传感器之间的距离及其夹角有关。研究结果将为CFRP结构的动态监测领域提供了实验参考。     

Distributed Fiber-Optic Sensor for Dynamic Strain Measurement

A novel Brillouin-based distributed sensing technique is presented that can obtain the strain profile of the entire sensing fiber with a single optical pulse. Experimentally obtained spectra show that this comb excited pump signal is capable of strain and temperature measurement in a dynamic system. The results show the expected sinusoidal strain profile for a 12 s periodic strain cycle applied to the test fiber. The strain distribution for the entire fiber was obtained in 256 mus , thereby demonstrating for the first time, the potential to measure dynamic strains up to 3.9 kHz with 12 m resolution. Increased acquisition speed comes at the expense of achievable spatial resolution.     

Fiber-Optic Magnetostriction Sensor for Free Oxygen Concentration

A simple design is suggested for a free oxygen sensor capable of recording free oxygen concentration at the level of about 10²² m^–3 with a predicted linear measurement range of four to five orders of magnitude.     

新型三线圈式滑油磨粒在线监测传感器

润滑油是以发动机为代表的机械设备的血液,其中携带了大量零部件的磨损颗粒.这些磨损颗粒反映了机械设备的运行状态,对其进行监测可以对发动机的早期故障进行预测,为发动机的维修与保养提供依据.为了实现滑油磨粒的实时在线监测,采用有限元分析方法对感应式滑油磨粒在线监测传感器进行了研究,以此为依据设计了一种以平面线圈作为感应线圈、螺线管为激励线圈的环绕微通道的新型三线圈式滑油磨粒在线监测传感器,并制作了原型器件,进行了滑油磨粒敏感能力测试.结果表明,该监测系统原型能够检测到100μm以下的铁磁性金属颗粒,且能同时检测到非铁磁性铜颗粒.     

High Sensitivity Fiber Bragg Grating Pressure Sensor Using Thin Metal Diaphragm

A high sensitivity pressure sensor design without a polymer transducer is demonstrated in this paper. The sensor uses a thin metal diaphragm as a pressure transducer instead of a polymer. The sensor is tested to a maximum pressure of 100 psi and has a sensitivity of 0.0115 nm/psi, which matches the calculated sensitivity of 0.0127 nm/psi. The sensor is provides accurate measurement of the pressure and shows good repeatability in its readings. The sensor is also tested at the flow loop of the University of Tulsa, and shows a good match with the pressure readings of the flow loop.     

新型分布式布喇格光纤光栅传感系统的研究

提出了一种新型分布式布喇格光纤光栅(FBG)传感系统.为了满足一个大型工程同时监测上百个不同位置的要求,将这一百个点分成若干组,每组构成一个小区域,每个小区域由四个波长相同的光栅组成,这样就满足了在一条光纤上刻一百个光栅的要求.当某点温度发生变化时,该区域的最高温度可测得;若此最高温度超过警戒温度,则系统发出报警信号,进而对这个小区域进行整体降温处理.在理论分析的基础上,对多组不同波长的光纤光栅进行了温控对比实验,在10～110℃的温度范围内,FBG的中心波长随温度变化呈良好的线性,线性度达到99.6%以上.实验表明该系统具有精度高、适用于分布式多点测量的特点.