本文關(guān)鍵詞： 氫致鼓泡 應(yīng)力強度因子 J積分 剩余強度　出處：《重慶科技學(xué)院》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：氫致鼓泡缺陷是輸氣管道中較常見的一種管道缺陷,輸氣管道一旦出現(xiàn)氫致鼓泡缺陷而不及時處理,很容易造成管道失效,從而帶來經(jīng)濟損失和人員傷亡。鑒于此,本文建立氫致鼓泡裂紋的有限元模型,計算不同工況下氫致鼓泡裂紋的斷裂參量并判斷裂紋開裂擴展的趨勢;模擬氫致鼓泡裂紋的擴展狀態(tài),探索氫致鼓泡在管道內(nèi)擴展的一般規(guī)律;最后計算缺陷管道的剩余強度,以確保輸氣管道的安全運行。本課題的研究具有重要的工程實際意義及一定的理論價值。本文首先利用ABAQUS有限元軟件建立了氫致鼓泡管道的有限元模型;根據(jù)建立的有限元模型計算不同工況下的斷裂參量并得出了規(guī)律:隨著鼓泡裂紋的橢圓率(b/a)、內(nèi)壓(P)、氫壓(Pq)、裂紋長度(a)的增大,對應(yīng)的斷裂參量增大,同時裂紋擴展的可能性也增大;隨著鼓泡裂紋深度(h)的增加,對應(yīng)的斷裂參量減小,說明越靠近管道內(nèi)壁面的鼓泡越有擴展的危險。其次,通過對竹渠線管道鼓泡的擴展模擬驗證了有限元模型的正確性,通過對不同情況下鼓泡裂紋的擴展模擬發(fā)現(xiàn):在管道直徑、內(nèi)壓及裂紋初始直徑一定時,氫壓越大鼓泡高度和直徑就越大,且鼓泡高度、鼓泡直徑與氫壓的關(guān)系為二次拋物線函數(shù)關(guān)系。對兩個鼓泡的管道進行模擬發(fā)現(xiàn):當兩個鼓泡之間的距離小于半徑為5 mm的圓周范圍以內(nèi)時,必須考慮兩個鼓泡的相互作用,當兩個鼓泡之間相隔的距離大于半徑為60 mm的圓周范圍以外時,兩個鼓泡的相互作用比較微弱,可以只選取其中一個鼓泡進行模擬計算。在次,經(jīng)過計算得出了t=20℃、30℃、100℃、200℃ 時氫壓-總濃度的關(guān)系圖,也得出了DN=200、350、500、650、800 mm時氫壓-鼓泡高度、氫壓-鼓泡直徑的關(guān)系圖。根據(jù)管道中濃度計算出鼓泡處總氫濃度可以得出鼓泡處的氫壓強度值,由此可以根據(jù)趨勢圖查出此氫壓下的鼓泡高度及鼓泡直徑值,從而計算出該情況下的剩余強度。最后,運用有限元法對不同氫壓下氫致鼓泡管道的剩余強度進行了計算與評價,得出了不同氫壓下缺陷管道的剩余強度值。
[Abstract]:Hydrogen bubble defect is a common pipeline defect in gas transmission pipeline. Once hydrogen bubble defect occurs in gas pipeline without timely treatment, it is easy to cause pipeline failure, resulting in economic losses and casualties. In this paper, the finite element model of hydrogen-induced bubbling crack is established, the fracture parameters of hydrogen-induced bubbling crack under different working conditions are calculated and the tendency of crack crack propagation is judged, the propagation state of hydrogen-induced bubbling crack is simulated, To explore the general rules of hydrogen induced bubbling in the pipeline, and finally to calculate the residual strength of the defective pipe, In order to ensure the safe operation of gas transmission pipeline, the research of this subject has important practical significance and certain theoretical value. Firstly, the finite element model of hydrogen induced bubbling pipeline is established by using ABAQUS finite element software. According to the established finite element model, the fracture parameters under different working conditions are calculated and the rules are obtained: the corresponding fracture parameters increase with the increase of the ellipse ratio of bubbling crack (b / a), the internal pressure (P), the hydrogen pressure (PQ), and the crack length (a). At the same time, the possibility of crack growth is also increasing, and with the increase of bubble crack depth, the corresponding fracture parameters decrease, which indicates that the blistering near the inner surface of the pipe is more dangerous. Secondly, The correctness of the finite element model is verified by the simulation of the bubble propagation of the bamboo canal pipeline. The simulation of bubble crack propagation under different conditions shows that when the pipe diameter, internal pressure and the initial diameter of the crack are fixed, the results are as follows: (1) when the pipe diameter, internal pressure and initial diameter of the crack are fixed, The greater the hydrogen pressure, the bigger the bubble height and diameter, and the higher the bubble height, The relationship between bubble diameter and hydrogen pressure is a quadratic parabola function. It is found that the interaction of two bubbles must be considered when the distance between two bubbles is less than the circumference range of 5 mm radius. When the distance between two bubbles is larger than a radius of 60 mm, the interaction between the two bubbles is weak, only one of the bubbles can be selected for simulation. The relationship diagram of hydrogen pressure-total concentration at 30 鈩，

本文編號：1519062