本文關(guān)鍵詞： 焊接接頭 力學(xué)性能不均勻性 蠕變 裂尖應(yīng)力應(yīng)變　出處：《西安科技大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：應(yīng)力腐蝕開裂(SCC)是核電一回路安全端異種金屬焊接接頭在服役過程中的一種重要失效形式,而SCC擴(kuò)展是裂尖微觀力學(xué)和電化學(xué)反應(yīng)交互作用下的氧化膜破裂與再生成過程。近年來的研究顯示,裂尖高應(yīng)力區(qū)的蠕變對SCC裂尖氧化膜的破裂有一定的影響。為了了解焊接接頭區(qū)高應(yīng)力條件下裂尖蠕變特性及其對SCC擴(kuò)展速率的影響,本文借助ABAQUS有限元分析軟件,詳細(xì)分析了焊接接頭SCC裂紋高應(yīng)力蠕變前后的裂尖力學(xué)場。主要完成的工作有:(1)以常用的核電焊接材料鎳基182合金為研究對象,借助ABAQUS有限元軟件及其重啟動功能,對低溫高應(yīng)力條件下裂尖蠕變過程進(jìn)行分析,得到了裂尖微觀力學(xué)場及相關(guān)力學(xué)參量隨蠕變時間推進(jìn)的變化規(guī)律。(2)以鎳基182合金-熱影響區(qū)-316L不銹鋼的異種金屬焊接接頭的簡化模型為研究對象,考慮材料力學(xué)性能不均勻性的影響,建立了焊接接頭的裂尖數(shù)值模擬分析模型,對蠕變前后裂尖力學(xué)場的分布變化規(guī)律和蠕變情況進(jìn)行分析;并對裂紋分別萌生于焊材區(qū)和熱影響區(qū)時的裂尖力學(xué)場進(jìn)行研究,得到初始裂紋位置對裂尖應(yīng)力應(yīng)變等參量的影響規(guī)律。(3)基于修正的氧化膜破裂預(yù)測模型(FA模型),對低溫高應(yīng)力蠕變主導(dǎo)下的應(yīng)力腐蝕裂紋尖端蠕變率及SCC裂紋擴(kuò)展速率進(jìn)行計算,得到了焊接接頭材料力學(xué)性能不均勻性對SCC裂紋擴(kuò)展速率的影響規(guī)律。
[Abstract]:Stress corrosion cracking (SCC) is an important failure form of safety end dissimilar metal welded joints in nuclear power plant. SCC expansion is a process of oxide film rupture and reformation under the interaction of micromechanics and electrochemical reaction of crack tip. In order to understand the creep characteristics of SCC crack tip under high stress condition and its influence on the SCC growth rate, this paper makes use of the ABAQUS finite element analysis software to study the creep behavior of the crack tip in the high stress zone of the crack tip and the rupture of the oxide film at the crack tip. The crack tip mechanical field before and after high stress creep of SCC crack in welded joint is analyzed in detail. The main work accomplished is: 1) taking the common nuclear power welding material nickel-based 182 alloy as the research object, with the help of ABAQUS finite element software and its restarting function, The creep process of crack tip under low temperature and high stress is analyzed. The micromechanical field of crack tip and the variation of relative mechanical parameters with creep time are obtained. The simplified model of dissimilar metal welded joints of Ni-based 182 alloy-heat affected zone stainless steel is studied. Considering the influence of non-uniformity of mechanical properties of materials, a numerical simulation analysis model of crack tip of welded joint is established, and the distribution of mechanical field and creep of crack tip before and after creep are analyzed. The mechanical field of crack tip is studied when the crack originates in the welding material area and the heat-affected zone, respectively. The influence of initial crack location on stress and strain of crack tip is obtained. (3) based on the modified oxide film fracture prediction model and FA model, the creep rate of stress corrosion crack tip and SCC crack expansion under low temperature and high stress creep are studied. The expansion rate is calculated, The effect of nonuniformity of mechanical properties of welded joints on SCC crack growth rate is obtained.
【學(xué)位授予單位】：西安科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TG407

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