【摘要】：近年來,管道泄漏事故的頻繁發(fā)生對管道泄漏監(jiān)測技術提出了新的要求,一是要提高定位精度;二是不遺漏小泄漏信號;三是要求投資少,具有經(jīng)濟性。這就需要詳細分析管道的受力狀況,確定應力容易集中受損的部位,合理布設傳感器,降低成本,提高監(jiān)測效率。本文主要是通過對長距離輸油管道易損部位的研究,解決光纖光柵傳感器的合理布設問題。利用ANSYS大型有限元分析軟件,通過編寫子程序,采用高斯移動熱源,模擬了管道焊縫的焊接和冷卻過程,研究發(fā)現(xiàn)焊件冷卻后在焊縫位置殘余應力達到最大。依據(jù)材料力學和彈塑性力學理論,建立了理想彎頭在內(nèi)壓載荷作用下的軸向應力和環(huán)向應力模型。運用ANSYS和FLUENT軟件分別對理想彎頭和橢圓彎頭在內(nèi)壓載荷和流體介質(zhì)載荷作用下的受力情況進行了分析,對比發(fā)現(xiàn),實際應用中彎頭的最大應力位置偏向于彎頭中性線處。推導出了變徑彎管和變徑直管在內(nèi)壓載荷作用下的軸向應力和環(huán)向應力數(shù)學模型。利用有限元分析軟件模擬了變徑直管和變徑彎管在內(nèi)壓載荷和流體介質(zhì)載荷作用下的受力情況,結(jié)果顯示變徑直管的最大應力位于大端口處,變徑彎管的最大應力位于大端內(nèi)拱的入口處,把實驗結(jié)果和理論推導的模型計算結(jié)果相比較,驗證了數(shù)學模型的準確性。在詳細分析光纖光柵傳感器對溫度和應變傳感機理的基礎上,將一種丁基橡膠合成的聚合物應用到光纖光柵碳氫化合物傳感探頭中,有效的解決了溫度—應變的“交叉敏感”問題。最后,將研究成果應用到傳感器在管道的布設中,使傳感器的布設更具敏感性和經(jīng)濟性,研究成果對實際監(jiān)測系統(tǒng)的建設具有指導作用。
[Abstract]:In recent years, the frequent occurrence of pipeline leakage accidents has put forward new requirements for pipeline leakage monitoring technology, one is to improve the positioning accuracy, the other is not to omit small leakage signals, and the third is to require less investment and be economical. It is necessary to analyze the stress condition of the pipeline in detail, determine the position where the stress is easily concentrated and damage, arrange the sensor reasonably, reduce the cost and improve the efficiency of monitoring. In this paper, the problem of the reasonable placement of fiber Bragg grating sensors is solved by studying the vulnerable position of long distance oil pipeline. The welding and cooling processes of pipe welds were simulated by using ANSYS software, by writing subroutine and using Gao Si moving heat source. It was found that the residual stress of welded parts reached maximum after cooling. Based on the theory of material mechanics and elastoplastic mechanics, the axial and circumferential stress models of ideal elbows under internal pressure are established. The internal pressure load and fluid medium load of ideal and elliptical elbows are analyzed by using ANSYS and FLUENT software respectively. It is found that the position of the maximum stress of the elbows deviates to the neutral line of the elbows in practical application. The mathematical models of axial stress and circumferential stress of curved pipe with variable diameter and straight pipe with variable diameter under internal pressure are derived. The finite element analysis software is used to simulate the stress of variable diameter straight pipe and variable diameter bend pipe under internal pressure and fluid medium load. The results show that the maximum stress of variable diameter straight pipe lies at the big port. The maximum stress of the curved pipe with variable diameter lies at the entrance of the inner arch of the large end. The accuracy of the mathematical model is verified by comparing the experimental results with the calculated results of the theoretical model. Based on the detailed analysis of temperature and strain sensing mechanism of fiber Bragg grating sensor, a kind of polymer synthesized by butyl rubber was applied to fiber grating hydrocarbon sensing probe. Effectively solves the temperature-strain "cross sensitivity" problem. Finally, the research results are applied to the sensor layout in the pipeline, which makes the sensor layout more sensitive and economical. The research results have a guiding role in the construction of the actual monitoring system.
【學位授予單位】：燕山大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TE973.6;TP212

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本文編號：2346022