共查询到20条相似文献,搜索用时 859 毫秒
1.
2.
Fiber optic sensing technology is used extensively in several engineering fields, including smart structures, health and usage monitoring, non-destructive testing, minimum invasive sensing, safety monitoring, and other advanced measurement fields. A general optical fiber consists of a core, cladding, and coating layers. Many sensing principles require that the cladding or coating layer should be removed or modified. In addition, since different sensing systems are needed for different types of optical fibers, it is very important to find and sort out the suitable cladding or coating removal method for a particular fiber. This study focuses on finding the cladding and coating stripping methods for four recent specialty optical fibers, namely: hard polymer-clad fiber, graded-index plastic optical fiber, copper/carbon-coated optical fiber, and aluminum-coated optical fiber. Several methods, including novel laser stripping and conventional chemical and mechanical stripping, were tried to determine the most suitable and efficient technique. Microscopic investigation of the fiber surfaces was used to visually evaluate the mechanical reliability. Optical time domain reflectometric signals of the successful removal cases were investigated to further examine the optical reliability. Based on our results, we describe and summarize the successful and unsuccessful methods. 相似文献
3.
4.
光纤传感技术已广泛应用于航空航天、石油化工、电子电力、土木工程、生物医药等领域,其技术形式主要体现为分立式和分布式.分立式光纤传感技术利用光纤敏感器件作为传感器来感知被测参量的变化,光纤作为光信号的传输通道连接光纤传感器及后端的解调装置;分布式光纤传感系统基于光纤瑞利散射、拉曼散射或布里渊散射等光学效应,利用光纤本身作为传感器,可对沿途的光信号进行大范围、长距离传感.本文介绍了分立式与分布式光纤传感中主要关键技术的研究进展,并对未来的研究和发展方向进行了探讨. 相似文献
5.
基于光纤布拉格光栅传感器的光纤光栅智能夹层试验研究 总被引:18,自引:4,他引:14
传感元件与复合材料的一体化是智能结构研究的最终目标之一。设计一种具有自诊断功能的标准化、模块化光纤智能夹层系统,正是实现这种一体化最有潜力的技术途径。采用聚酰亚胺薄膜制作了基于光纤布拉格光栅(FBG)传感器的光纤光栅智能夹层,对智能夹层中光纤布拉格光栅传感器的应变、温度特性进行了标定试验,并建立了基于光纤布拉格光栅传感器光纤光栅智能夹层的应变、温度测量模型。试验表明,智能夹层内布拉格光栅波长偏移与应变、温度之间具有良好的线性关系。不过在温度测量时,必须考虑被埋人结构的热膨胀效应。利用光纤光栅智能夹层内光纤布拉格光栅传感器网络和先进信息处理技术,可以建立结构损伤主动、在线和实时监测系统。 相似文献
6.
机敏材料中竹节型光纤传感阵列及其信号处理 总被引:9,自引:1,他引:8
提出了一种新颖的,采用刻纹多模光纤组成的可用于机敏材料与结构的竹节形光纤传感阵列,并探索采用人工神经网络来处理其输出的并行分布式传感信号,由此和到材料的内应变,应力及损伤的大小及其位置等信息。 相似文献
7.
A novel structure in which a short optical fiber stub containing a weakly tilted Bragg grating is spliced to another slightly offset fiber. The total power reflected from this structure is independent of temperature and occurs in two well-defined wavelength bands, only one of which reflects a different amount of power as the fiber stub bends or vibrates. The smart sensing structure presents an extremely high sensitivity for microbending, and its frequency response has been tested to higher than 2 kHz so far in temperature-immune vibration measurements via cost-effective power detection. 相似文献
8.
准分布式光纤传感系统在土木工程、能源勘测、航空航天、国防、化工等领域一直发挥着不可替代的重要作用。以微波光子学为基础的准分布式光纤传感解调技术被广泛应用于光纤复用系统的快速、高精度的信号解调与传感器定位。与传统的光学波长解调方案相比,该技术大幅提高了系统的解调速率,弥补了传统解调方法在传感器定位方面的缺陷。本文主要介绍了近年来国内外在基于微波光子学的准分布式光纤传感解调领域的研究进展,从光纤光栅准分布式传感系统和光纤法布里-珀罗准分布式传感系统两方面入手,对比分析了现有的数种微波解调光纤准分布式系统的优缺点,并对基于微波光子学的准分布式光纤传感解调技术的未来发展方向进行了总结与展望。 相似文献
9.
光纤超声传感器通过检测光纤内传输光的强度、波长、相位、偏振态等参数感知超声波的相关信息.相比于传统的电类超声换能器,光纤超声传感器能够实现宽频带超声波信号的高灵敏探测,且其良好的抗干扰能力和复用性,可有效地提高超声波探测的可靠性和效率,在水下国防安全、生物成像、无损探伤、地震物理模型成像等领域具有巨大的应用潜力.目前,按照传感结构,光纤超声传感器可分为光纤强度调制型、光纤干涉型和光纤光栅型,并在不同方面发挥着各自的优势,均受到关注.本文主要综述了这几种传感器的传感机理、实现方法、发展现状,总结了光纤超声传感器的几个应用领域及面临的科学技术挑战,重点讨论了光纤超声传感器作为一种新技术应用于地震物理模型成像. 相似文献
10.
白光干涉双环传感网络理论与实验研究 总被引:3,自引:0,他引:3
构造了一种基于双环形拓扑结构的白光干涉光纤传感网络.可用于智能结构中准分布应变或温度的测量。光纤传感网络基于空分多路复用技术(SDM).目的是增强带载能力.降低单点传感器的测量成本,并借助丁双端口问询技术.增强传感网络的抗毁坏能力。分析了环形网络结构的低相干多路复用原理.根据空分复用的光程匹配条件.推导了传感器干涉信号的强度特性。实验中对连接9个传感器的双环传感网络特征及其抗损坏特性进行了验证.并对实验结果进行了分析和讨论。 相似文献
11.
Haroldo T. Hattori Vitor M. Schneider Osni Lisba Rogrio M. Cazo 《Optics & Laser Technology》2001,33(5)
Raman and Brillouin effects have found special applications in distributed sensing for smart materials and structures. In these sensors, the fiber acts as a distributed sensor, sensing strain and temperature over a range of tens of kilometers and, at the same time, carries this information to the installation that will process them. In order to optimize the fiber to operate under the Brillouin and Raman regimes, a special elliptical fiber with small effective area has been designed, which will allow these sensors to cover longer distances and/or employ lower power lasers. 相似文献
12.
13.
SMS光纤结构是一种近年来新兴的光纤器件,该结构光纤具有结构简单、易于实现、成本低廉、灵敏度高和无温度应力交叉敏感等特性.在光纤传感技术领域是一种继光纤光栅之后的具有广泛发展前景的光纤器件.从理论上分析了SMS结构和SMS级联结构的光纤传感原理,并从实验上研究了SMS结构和级联SMS结构的温度传感特性.实验表明:对于SMS结构光纤传感器,随着温度的增加,特征波长移动量逐渐增加,向长波方向漂移了4.05 nm,其传感器的温度灵敏度为15.76 pm/℃;对于级联SMS结构的光纤传感器,级联后不改变原来SMS结构的中心波长的位置,两个SMS结构仍然是独立的,不相互影响.所以说将两个SMS结构串联是可行的,可以用于温度和应力的同时测量,也可以用于分布式光纤传感器. 相似文献
14.
In the present article, an improved genetic algorithm (GA) based optimal vibration control of smart fiber reinforced polymer (FRP) composite shell structures has been presented. Layered shell finite elements have been formulated and the formulation has been validated for coupled electromechanical analysis of curved smart FRP composite structures having piezoelectric sensors and actuators patches. An integer-coded GA-based open-loop procedure has been used for optimal placement of actuators for maximizing controllability index and a real-coded GA-based linear quadratic regulator (LQR) control scheme has been implemented for optimal control of the smart shell structures in order to maximize the closed-loop damping ratio while keeping actuators voltages within the limit of breakdown voltage. Results obtained from the present work show that this combined GA-based optimal actuators placement and GA-based LQR control scheme is far superior to conventional active vibration control using LQR schemes and simple placement of actuators reported in literatures. Results also show that the present improved GA-based combined optimal placement and LQR control scheme not only leads to increased closed-loop damping ratio but also shows a drastic reduction in input/actuation voltage compared to the already published results. 相似文献
15.
A two-loop-based low-coherence multiplexing fiber-optic sensor network is proposed and demonstrated. It greatly extends the multiplexing capacity of this kind of sensor. A practical implementation of this scheme uses a popular amplified spontaneous emission light source and standard single-mode fiber, which are commonly used in the communications industry. The sensor's two-loop topology is completely passive. Absolute length measurements can be obtained for each sensing fiber segment for use in measuring the quasi-distribution strain or temperature. For large-scale smart structures this technique not only extends the multiplexing potential but also provides a redundancy for the sensing system. This means that the two-loop sensor network can break down at several points and the sensing system will still work even if some of the embedded two-loop sensors have been destroyed. The robustness of the nine-sensor two-loop sensing network is investigated and discussed. 相似文献
16.
17.
在复合材料结构部件与蒙皮中埋入光纤传感器,对材料的各种物理状态进行监测,并随时对复合材料与结构中的各类损伤进行探测与预报,称为光纤灵巧结构与蒙皮,该技术受到各国政论与军方的高度重视,成为90年代材料与传感技术的一大观点,本文介绍灵巧结构一蒙皮光纤传感器的工作原理,应用等的研究进展。 相似文献
18.
19.
In the last decade,the functionally graded carbon nanotube reinforced composites(FG-CNTRCs)have attracted considerable interest due to their excellent mechanical properties,and the structures made of FG-CNTRCs have found broad potential applications in aerospace,civil and ocean engineering,automotive industry,and smart structures.Here we review the literature regarding the mechanical analysis of bulk CNTR nanocomposites and FG-CNTRC structures,aiming to provide a clear picture of the mechanical modeling and properties of FG-CNTRCs as well as their composite structures.The review is organized as follows:(1)a brief introduction to the functionally graded materials(FGM),CNTRCs and FG-CNTRCs;(2)a literature review of the mechanical modeling methodologies and properties of bulk CNTRCs;(3)a detailed discussion on the mechanical behaviors of FG-CNTRCs;and(4)conclusions together with a suggestion of future research trends. 相似文献