本文關(guān)鍵詞： 納應(yīng)變測量 動態(tài)測量 分布式光纖傳感 相位敏感光時域反射計　出處：《哈爾濱工業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：近年來,隨著人們在生產(chǎn)、生活中安全意識的提高,對橋梁、隧道、路基等建筑物結(jié)構(gòu)健康監(jiān)測的需求日益增大。其中,應(yīng)變是一個相當(dāng)重要的監(jiān)測物理量,對于目前已有技術(shù)來說,應(yīng)變分辨率普遍在微應(yīng)變量級,難以滿足某些特殊應(yīng)用場合的需求,因此研究具有動態(tài)定量測量性能的納應(yīng)變傳感技術(shù)具有重要的研究價值與廣闊的應(yīng)用前景。本文研究的動態(tài)納應(yīng)變定量測量技術(shù)是基于相位敏感光時域反射技術(shù)(Φ-OTDR)實(shí)現(xiàn)的,具有高精度、長距離、分布式測量等優(yōu)勢,可響應(yīng)外界極微弱的應(yīng)力或溫度變化。本文具體研究內(nèi)容如下:首先,從光纖散射的基本理論出發(fā),詳細(xì)分析了傳統(tǒng)OTDR和Φ-OTDR的基本原理,通過建立理論模型,從散射光相位、強(qiáng)度兩方面詳細(xì)推導(dǎo)了Φ-OTDR的應(yīng)變傳感機(jī)制。其次,通過建立Φ-OTDR散射數(shù)學(xué)模型,對Φ-OTDR散射過程進(jìn)行了數(shù)學(xué)仿真,同時分別對散射光相位、強(qiáng)度與應(yīng)變的定量關(guān)系進(jìn)行了仿真實(shí)驗。仿真結(jié)果證明固定間隔下散射光相位差變化量與應(yīng)變量之間存在線性關(guān)系,散射光強(qiáng)度標(biāo)準(zhǔn)差與應(yīng)變量之間存在線性關(guān)系。最后,搭建了Φ-OTDR動態(tài)納應(yīng)變定量測量實(shí)驗裝置,通過外差探測和IQ解調(diào)對散射光的強(qiáng)度和相位信息進(jìn)行實(shí)時解調(diào)。實(shí)驗測定了散射光強(qiáng)度標(biāo)準(zhǔn)差與應(yīng)變定量關(guān)系,通過增大樣本數(shù)據(jù)長度減緩光纖各個位置處的應(yīng)變靈敏度不一致性,此種方法所能達(dá)到的系統(tǒng)應(yīng)變分辨率為6 nε。此外,本文提出通過測量固定間隔處的相位差來進(jìn)行應(yīng)變定量測量,這也是一種測量光纖應(yīng)變折射率系數(shù)的新方法。實(shí)驗測定所用的熊貓型保偏光纖折射率應(yīng)變系數(shù)為-0.375ε-1,系統(tǒng)應(yīng)變靈敏度為8.71 mrad/(nε·m),系統(tǒng)應(yīng)變分辨率為1 nε/2 nε,分別對應(yīng)5m/2.5 m空間分辨率。在此基礎(chǔ)上對系統(tǒng)動態(tài)測量性能進(jìn)行了研究,系統(tǒng)可響應(yīng)頻率為24 Hz,應(yīng)變幅度為50 nε的三角波應(yīng)變信號,同時也可響應(yīng)頻率為188Hz的光纖共振信號,證明系統(tǒng)具備動態(tài)納應(yīng)變定量測量的能力。
[Abstract]:In recent years, along with the people in the production, improve the safety awareness of life, on the bridge, tunnel, health monitoring roadbed structure increasing demand. Among them, strain monitoring is a very important physical quantity for the present technology, strain resolution common in micro strain level, difficult to meet some special applications application requirements, so research on nano strain sensing technology with dynamic quantitative measurement of performance has important research value and application prospect. This paper studies the wide dynamic strain measurement technology is a quantitative nano phase sensitive optical time domain reflectometry (-OTDR) based on the realization of the high precision, long distance, distributed mode and other advantages. Can be extremely weak response to external stress or temperature changes. The contents of this paper are as follows: firstly, starting from the basic theory of optical scattering, a detailed analysis of the traditional OTDR and -OTDR. The basic principle, by establishing the theoretical model, the light scattering phase, two aspects of strength are derived in detail with -OTDR strain sensing mechanism. Secondly, through the establishment of mathematical model of scattering phi -OTDR, Phi -OTDR scattering process by mathematical simulation, at the same time respectively on light scattering phase, the quantitative relationship between strength and strain experiments. The simulation results show that the linear relationship between the fixed interval under the light scattering phase variation and variable, the linear relationship between the scattering intensity and standard deviation should be variable. Finally, build the dynamic strain measurement with -OTDR nano experimental device, real-time demodulation intensity and phase information of the light scattering by heterodyne detection and IQ demodulation. The light scattering intensity of standard deviation and the quantitative relationship between the strain measured by strain increases the sensitivity of sample data length slow fiber at each location is not consistent, this Strain resolution method can reach 6 n. In addition, this paper presents the measurement of phase difference at fixed intervals for quantitative measurement of strain, which is a new method for measuring the refractive index of the optical fiber strain. Determination of the panda type polarization maintaining fiber strain coefficient is -0.375 ~ -1. Strain sensitivity is 8.71 mrad/ (n - M), strain resolution system is 1 N E /2 n e 5m/2.5 m, respectively. The spatial resolution on the basis of the research on the dynamic performance measurement system, response frequency is 24 Hz, the strain amplitude of triangular wave signal strain 50 N epsilon, at the same time can response frequency for optical fiber resonance signal 188Hz, proved that the system has the capability of dynamic strain that quantitative measurement of.

【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN253

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本文編號：1526966