發(fā)布時(shí)間：2018-03-19 00:18

  本文選題：聲發(fā)射信號　切入點(diǎn)：有限元仿真　出處：《沈陽工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：石油儲(chǔ)罐的建設(shè)促進(jìn)了我國經(jīng)濟(jì)的快速發(fā)展，但同時(shí)也帶來潛在的危險(xiǎn)，儲(chǔ)存介質(zhì)具有高溫、高壓、高腐蝕性等特征，特別罐底容易發(fā)生因腐蝕而引起的破裂等損傷。聲發(fā)射檢測技術(shù)作為一種新型的無損檢測方法已經(jīng)廣泛應(yīng)用于儲(chǔ)罐罐底腐蝕檢測中。本文主要從罐底腐蝕機(jī)理，腐蝕產(chǎn)生的聲發(fā)射信號特征，如何根據(jù)腐蝕產(chǎn)生的聲發(fā)射信號判斷腐蝕進(jìn)程等幾個(gè)方面進(jìn)行研究。 本文介紹了聲發(fā)射信號的產(chǎn)生原理和罐底腐蝕機(jī)理。由于罐底長期承受來自油品和自身重量的壓力，同時(shí)由于底板和地基等變化而變形，造成罐底與雨水、露水或其他電解質(zhì)直接接觸發(fā)生電化學(xué)腐蝕。針對儲(chǔ)罐材料、所處環(huán)境及常見腐蝕類型，在此著重研究了鋼板的電偶腐蝕聲發(fā)射機(jī)理。 綜合分析電偶腐蝕機(jī)理和腐蝕產(chǎn)生聲發(fā)射信號的原理，結(jié)合電化學(xué)腐蝕動(dòng)力學(xué)理論，借助COMSOL有限元仿真軟件建立二維有限元模型。模擬了鋼板局部腐蝕缺陷的擴(kuò)展路徑和能量分布，直觀地描述了在腐蝕過程中交換電流密度，電偶腐蝕速度和電極電勢。由于影響電偶腐蝕的因素較復(fù)雜，本文針對比較重要的因素，即電偶腐蝕中電極材料的陰、陽極面積比進(jìn)行仿真研究。結(jié)果表明，電極電流在偶接處最大，所以金屬的溶解程度在該點(diǎn)最大；陽極交換電流的峰值位于偶接處，由于電極表面存在壓降，因此遠(yuǎn)離偶接處的陽極交換電流密度逐漸減小。隨著加載時(shí)間的推移，電偶腐蝕電極的各點(diǎn)處的交換電流密度并沒有明顯的變化；在相同條件下，陰極面積越大造成的電偶腐蝕現(xiàn)象越明顯，即單位時(shí)間內(nèi)電偶腐蝕速率越大，但是二者并不成線性關(guān)系。分析得到的不同的仿真結(jié)果，對比腐蝕原理驗(yàn)證建立的仿真模型的正確性，為實(shí)驗(yàn)提供理論依據(jù)。 根據(jù)課題需要使用PIC-2聲發(fā)射檢測系統(tǒng)對鋼板分別在空氣中，10%氯化鈉溶液中以及鋼板-鋁板在10%氯化鈉溶液中發(fā)生電偶腐蝕行為進(jìn)行長時(shí)間連續(xù)實(shí)時(shí)檢測。結(jié)果表明，單位時(shí)間內(nèi)腐蝕越嚴(yán)重的鋼板，產(chǎn)生的聲發(fā)射事件個(gè)數(shù)越多。通過腐蝕模擬實(shí)驗(yàn)數(shù)據(jù)與電偶腐蝕仿真結(jié)果相比，單位時(shí)間內(nèi)檢測到聲發(fā)射事件個(gè)數(shù)可以對電偶腐蝕速率進(jìn)行定性的判斷，，進(jìn)一步可根據(jù)量值變化推斷腐蝕趨勢。
[Abstract]:The construction of oil storage tanks has promoted the rapid economic development of our country, but at the same time, it also brings potential dangers. The storage medium has the characteristics of high temperature, high pressure, high corrosion and so on. As a new nondestructive testing method, acoustic emission (AE) detection technology has been widely used in tank bottom corrosion detection. In this paper, the corrosion mechanism of tank bottom is discussed. The characteristics of acoustic emission signals produced by corrosion and how to judge the corrosion process according to the acoustic emission signals produced by corrosion are studied. This paper introduces the generation principle of acoustic emission signal and the corrosion mechanism of tank bottom. The tank bottom and Rain Water are deformed because the bottom of the tank bears the pressure from oil and its own weight for a long time, at the same time, because of the change of bottom plate and foundation, etc. Electrochemical corrosion occurs in direct contact with dew water or other electrolytes. The acoustic emission mechanism of galvanic corrosion of steel plates is mainly studied in view of the environment and common corrosion types of tank materials. The mechanism of galvanic corrosion and the principle of acoustic emission signal generated by corrosion are analyzed synthetically, and combined with the theory of electrochemical corrosion kinetics, The two-dimensional finite element model is established by using the COMSOL finite element simulation software. The propagation path and energy distribution of the local corrosion defects of steel plate are simulated, and the exchange current density during the corrosion process is described intuitively. Due to the complexity of the factors affecting the galvanic corrosion, the anodic area ratio of the electrode material in the galvanic corrosion process is studied by simulation in this paper. The electrode current is the largest at the junction, so the dissolution degree of the metal is the largest at this point, and the peak value of the anode exchange current lies at the junction, because of the voltage drop on the electrode surface. As a result, the exchange current density of the anode away from the coupling site gradually decreases. With the loading time, the exchange current density at each point of the galvanic corrosion electrode does not change significantly; under the same conditions, The larger the cathode area, the more obvious the galvanic corrosion, that is, the larger the galvanic corrosion rate per unit time, but not the linear relationship between the two. Compare the corrosion principle to verify the correctness of the established simulation model, and provide a theoretical basis for the experiment. The galvanic corrosion behavior of steel plate in 10% NaCl solution in air and the galvanic corrosion behavior of steel plate and aluminum plate in 10% sodium chloride solution were detected by PIC-2 acoustic emission detection system for a long time. The results show that, The more seriously corroded the steel plate per unit time, the more acoustic emission events are generated. Compared with the simulation results of galvanic corrosion, the corrosion simulation data are compared with the results of galvanic corrosion simulation. The number of acoustic emission events per unit time can be used to judge the galvanic corrosion rate qualitatively, and the corrosion trend can be further inferred according to the quantity variation.
【學(xué)位授予單位】：沈陽工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TE988

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 戴光,徐彥廷,李偉,張穎;聲發(fā)射技術(shù)的應(yīng)用與研究進(jìn)展[J];大慶石油學(xué)院學(xué)報(bào);2001年03期

2 莫乾賜;鐘釗琪;吳兆輝;黃健;;聲發(fā)射技術(shù)在廣西大型壓力容器檢驗(yàn)中的應(yīng)用前景[J];大眾科技;2009年01期

3 侯素霞;羅積軍;徐軍;馬進(jìn);;基于聲發(fā)射技術(shù)的壓力容器應(yīng)力腐蝕檢測研究[J];腐蝕科學(xué)與防護(hù)技術(shù);2006年03期

4 王忠濱;;儲(chǔ)罐底板腐蝕檢測技術(shù)對比試驗(yàn)研究[J];裝備制造技術(shù);2013年07期

5 徐火力;;聲發(fā)射技術(shù)在球罐全面檢驗(yàn)中的應(yīng)用[J];能源與環(huán)境;2009年06期

6 楊瑞峰;馬鐵華;;聲發(fā)射技術(shù)研究及應(yīng)用進(jìn)展[J];中北大學(xué)學(xué)報(bào)(自然科學(xué)版);2006年05期

7 覃雄;謝世波;;靜態(tài)壓力容器內(nèi)壁的腐蝕與保護(hù)[J];黑龍江科技信息;2011年01期

8 崔麗娜;;儲(chǔ)罐檢測中聲發(fā)射技術(shù)的應(yīng)用[J];石油和化工設(shè)備;2008年04期

9 宋欣;馮麗鋒;;提高化工機(jī)械設(shè)備防腐蝕能力探討[J];石油和化工設(shè)備;2011年04期

10 黃艷仙;周建敏;牛顯春;;Zn/A_3鋼在海水中電偶腐蝕的研究[J];化學(xué)工程師;2009年11期

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