Fiber optic smart structures

Fiber optic sensors can be embedded into composite material used for a wide variety of lightweight structures supporting aircraft, spacecraft, automobiles and boats. Their environmental ruggedness has also allowed them to be embedded in concrete structures including buildings, dams, and bridges. Most recently it has been proposed that the very long gauge lengths associated with fiber sensors could be used to monitor widely dispersed natural structures such as earthquake fault lines and volcanic motion. This paper will review the fiber optic sensors associated with smart structures and how they are being applied     

用于灵巧结构的光纤应变／应力传感器

文章对灵巧结构中几种主要类型的光纤传器作了介绍，分析和比较，并对其中两种最有应用前景的传感器－－光纤Ｆａｂｒｙ－Ｐｅｒｏｔ干涉仪和光纤Ｂｒａｇｇ光栅传感器进行了比较详细的介绍。     

光纤机敏结构评述

介绍了光纤机敏结构的概念，效益及应用。对光纤机敏结构中光纤传感器、执行器、人工神经网络三大关键技术的现状与发展作了简单评述。     

Fiber optic sensors focus on smart systems

Materials with structurally integrated fiber-optic sensors, the first step toward smart structures, which continuously monitor their own vibration, internal strain and deformation, temperature, and structural integrity are described. It is shown that the Fabry-Perot fiber-optic strain sensor has capabilities that far exceed those of conventional foil strain gauges, which holds the promise of responding to acoustic emission signals while simultaneously tracking the high loads likely to be encountered in practical structures such as aircraft wings. The same sensing system may be able to monitor the degree of cure during fabrication of thermoset composite structures. The fabrication and characterization of such all-fiber, intrinsic Fabry-Perot strain sensors are discussed. Passive and active homodyne signal recovery techniques used in the fiber-optic sensor systems are also described     

一种光纤智能结构的载荷及损伤监测

提出一种新型的光纤智能结构监控系统,主要由光源组、光学系统、光电传感器、监控主机组成.分析了系统的工作原理,研究了基于此种新型光纤智能结构承载与损伤位置判别的方法,并进行了相应实验,得出相应的实验数据,并作出光纤网络输出光强与加载量的变化曲线图.经实验分析与讨论,实验数据与理论分析能较好地符合,结果表明这种新型光纤智能结构监控系统对结构的承载及损伤位置的判别方法具有快速、准确和可靠的优点,为特殊光纤智能结构的进一步应用提供了新途径.     

Vibration control of smart structures using an array of Fiber Bragg Grating sensors

Optical strain gauges, such as Fiber Bragg Grating (FBG) sensors, are widely used to monitor the health of structures and their state of deformation. This paper proposes exploiting the measurements of these sensors as feedback for active vibration control applications. The advantages of this solution are the possibility of monitoring a large number of sensors (to approximate distributed measurements) and of embedding them in carbon fiber structures with negligible load effects. Experimental tests confirm that smart structures with embedded FBG sensors can be profitably designed to suppress vibrations.     

光纤传声器概述

对光纤传声器的研究现状进行了总结.首先分别对强度型、光纤光栅型和F-P干涉型光纤传声器展开论述,通过对产品的技术现状对比,得出各类型光纤传声器的优劣势.之后对新型光学传声器进行了介绍,指出虽然新型光学传声器具有体积小、功耗低、成本低等优势,然而其主要针对特殊应用领域.最后阐述了作者在强度型光纤传声器方面的研究成果,为光纤传声器的进一步研究奠定了基础.     

光纤微振动传感器

利用光纤共振原理设计和实现了一种光纤微振动传感器。光纤微振动传感器主要有两种结构形式；带电的微振动传感器和不带电的微振动传感器，以适应不同环境的在线检测。     

Fiber optic microcellular radio

A distributed antenna system consisting of optical fiber connected canisters is proposed to replace or supplement the base station antennas required for cell splitting of growing cellular mobile radio systems. The end-to-end linear transmission of RF signal voltage can be maintained over the wide dynamic range of mobile radio. The technical feasibility of multiplexed subcarrier transmission using available lightwave components has been verified by signal-to-noise ratio and intermodulation distortion measurements. Measurements of a two-way audio link over both simulated and real radio paths have demonstrated the compatibility of a prototype lightwave transceiver, designed for the canister, with the existing base station and mobile equipment     

智能结构中的少模光纤传感器

介绍了在智能结构中具有广泛应用前景的光模光纤传感器，对其原理，组成和性能进行了评述，并讨论了一些存在的问题和今后的研究方向。     

光纤传感器及其应用

基于光纤的传感技术具有许多先天优势,使得它们在广泛的工业传感应用中具有很强的吸引力。本文采用从光纤传感器的基本结构、工作原理、分类及特点进行分析的方法,得出光纤传感器比传统的机电式传感器更适合在分布式传感和耐恶劣环境下可靠工作的结论。由于其起源于电信业,所以基于光纤的传感器可很容易集成到大规模光网络和通信系统中。     

Fiber optic polymer cure sensor

An in situ method is presented for monitoring the curing of polymeric compositions, including epoxy- and polymide-based composites. The sensor measures the difference between the refractive index of the cured and uncured composition, with the index increasing as polymerization proceeds. The method differs from all existing methods in that it relies on a self-referential differential measurement rather than on an absolute measurement, the sensor is totally independent of curing conditions and is sensitive to the extent of cure even at the latest stages. It can be used within the body of large composite structures undergoing curing in an autoclave, and it can indicate the end of cure without calibration of any kind     

Multifunction fiber optic sensing system for smart applications

The end of the twentieth century was witness to the merger of several technological disciplines that could eventually revolutionize engineering design philosophy and lead to the creation of intelligence within otherwise inanimate structures. This new technology will endow a structure with senses and the ability to react to its environment and change its state, shape and geometry. The key point for the practical realization of the so-called smart materials is the availability of robust and reliable structurally integrated sensors able to monitor the state of the structure. To this aim, a fiber optic multiparameter sensing system for process and structural health monitoring in concrete structures is presented. The reflectometric technique has been implemented for refractive-index measurements by using as transducer the fiber end/host interface. Results on the capability of the developed sensor to monitor the curing process of thermoset-based composites are presented. The integration with fiber Bragg gratings (FBGs) with the aim to perform temperature and strain measurements has been discussed. Two low-cost intensity-based demodulation techniques for FBGs interrogation have been developed and tested.     

Sensing and processing for smart structures

It has been only recently that research and development on smart structures has been identified as an interdisciplinary area of activity in its own right. One of the key functionalities required for a structure to be termed “smart” is an ability to sense. Recent developments in fiber optic sensing, noncontact sensor power/interrogation, and long gauge length sensors configured as matched filters will be critical to the successful development of the smart structures of the future. A formal definition of a smart structure is provided and sensing requirements and potential sensing alternatives are discussed. Some data processing options are then covered and near term application areas identified     

Fiber optic backbone boosts local-area networks

The evolving Fiber Distributed Data Interface (FDDI) for fiber optic networks, which greatly increases system capacity and flexibility, is discussed. The standard is described in terms of the ISO's Open Systems Interconnection (OSI) reference model. The initial FDDI standard defines four protocols: physical layer medium dependent, physical layer, media access control, and station management. Each of these is examined. Optical technology and the use of application-specific integrated circuits required by FDDI are discussed. Applications of FDDI and its future evolution are considered     

光纤陀螺技术及应用

简单回顾了光纤陀螺30年的技术研究和应用情况;介绍了光纤陀螺的基本原理,总结了光纤陀螺的特点和关键应用技术;以光纤陀螺在光电探测和卫星观测系统中的应用为主要背景,详细介绍了具有代表性的LN200系列光纤陀螺惯性系统的技术特点和应用情况;同时介绍了光纤陀螺在机载红外前视、红外天体观测平台和高精度对地观测卫星中的典型应用,为光纤陀螺在相关领域的应用提供了参考和依据。简单总结了我国光纤陀螺的发展和应用情况。经过30年的发展,光纤陀螺及相关技术已达到很高的水平,已成为惯性系统的主流和首选仪表。     

高分辨率光纤位移传感器

介绍了一种新型的光纤位移传感器，它基于全光纤法布里－珀罗干涉仪原理，采用了光反馈技术和共模抑制技术，有效地消除了环境的影响，趴有很高的测量稳定性，其分辨率高在１０＾－１０ｍ，可用二系统的状态监控和故障诊断及精密测量。     

Fiber optic LANs for the manufacturing environment

The physical layer requirements for local area networks (LANs) that satisfy the set of environmental requirements unique to factory automation applications are discussed. In many cases these requirements are best met with fiber-optic LANs compatible with the IEEE 802.3 (CSMA/CD) or 802.4 (token bus) network standards. Implementation of a passive fiber-optic star-coupler-based LAN is presented in terms of two simple fiber-optic system design rules. A number of applications of the passive star-coupler-technology LAN are briefly described to highlight the benefits of fiber optics as a data communication medium     

一种光纤温度传感器的研究

本文提出了一种可用于航空发动机进口温度测量的光纤传感系统，这种双光纤传感器是通过检测光偏振态的变化来测量温度特性的。以蓝宝石单晶片作为探头的敏感元件，可耐２０００℃以上的高温。并且利用蓝宝石晶体的双折射特性得到关于温度的信息，本文从物理模型和数学分析上证实了这种传感器的可行性，用光纤传感器代替传统的发动起进口温度测量系统,可以促进全权数字式电子探测系统再新一代航空发动机中的应用.