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  本文選題：異種金屬焊接接頭 + 彈塑性��； 參考：《西安科技大學(xué)》2017年碩士論文

【摘要】：核電安全端異種金屬焊接接頭受焊接工藝、材料微觀組織結(jié)構(gòu)、幾何不連續(xù)性和力學(xué)性能不均勻性的影響,其焊縫區(qū)域的裂紋擴展行為存在不確定性和不規(guī)律性。為了給異種金屬焊接接頭的安全評價提供一定幫助,本文以安全端異種金屬焊接接頭為研究對象,利用有限元軟件ABAQUS中的擴展有限元模塊,根據(jù)結(jié)構(gòu)的材料力學(xué)性能、受力狀況及設(shè)定的斷裂判據(jù)確定裂紋的啟裂位置及擴展行為,分析了異種金屬焊接接頭擴展裂紋尖端力學(xué)場的分布規(guī)律和裂紋擴展路徑的特點。完成的主要工作如下:(1)利用有限元軟件ABAQUS中的擴展有限元模塊,建立了彈塑性條件下異種金屬焊接接頭材料的裂紋擴展有限元模型,實現(xiàn)了均質(zhì)材料模型和異種金屬焊接接頭材料模型的裂紋擴展,提出了擴展有限元法和彈塑性斷裂力學(xué)相結(jié)合的裂紋擴展研究方法;(2)通過建立異種金屬焊接接頭四種材料的均質(zhì)模型,分析了不同材料在裂紋擴展過程中的裂尖力學(xué)場分布規(guī)律和裂紋擴展路徑特征,得到了材料抗拉強度、彈性模量和屈服強度變化對擴展裂紋尖端力學(xué)場及裂紋擴展路徑的影響規(guī)律,為研究異種金屬焊接接頭材料模型的裂紋擴展行為提供參照基準;(3)通過建立異種金屬焊接接頭材料的裂紋擴展有限元模型,分析了低碳鋼A508和316L不銹鍘中擴展裂紋尖端的力學(xué)場分布規(guī)律和裂紋擴展路徑特征,得到了抗拉強度、彈性模量和屈服強度失配對擴展裂紋尖端力學(xué)場及裂紋擴展路徑的影響規(guī)律。本文提出的基于擴展有限元在彈塑性條件下的異種金屬焊接接頭裂紋擴展行為研究方法,為確保核電焊接接頭在高溫高壓水環(huán)境下的安全運行具有重要意義。
[Abstract]:Under the influence of welding process, microstructure, geometric discontinuity and non-uniformity of mechanical properties, the crack propagation behavior in the weld zone is uncertain and irregular. In order to provide some help for the safety evaluation of dissimilar metal welded joints, this paper takes the safety end dissimilar metal welded joints as the research object, and makes use of the expanded finite element module in the finite element software ABAQUS, according to the mechanical properties of the materials of the structure. The stress condition and fracture criterion are used to determine the crack initiation position and propagation behavior. The distribution of mechanical field at the crack tip and the characteristics of crack propagation path of dissimilar metal welded joints are analyzed. The main work is as follows: (1) using the expanded finite element module in the finite element software ABAQUS, the crack propagation finite element model of dissimilar metal welded joint under elastoplastic condition is established. The crack propagation of homogeneous material model and dissimilar metal welded joint material model is realized. In this paper, a new method of crack propagation is presented, which combines the extended finite element method and elastic-plastic fracture mechanics. The homogenization model of four kinds of materials for dissimilar metal welded joints is established. The crack tip mechanical field distribution and crack propagation path characteristics of different materials during crack propagation are analyzed, and the tensile strength of the materials is obtained. The influence of the variation of elastic modulus and yield strength on the mechanical field and crack propagation path of propagating crack tip. In order to study the crack growth behavior of dissimilar metal welded joint material model, the finite element model of crack growth of dissimilar metal welded joint material is established. The mechanical field distribution law and crack propagation path characteristics of propagating crack tip in low carbon steel A508 and 316L stainless guillotine are analyzed, and the tensile strength is obtained. The effects of elastic modulus and yield strength on the crack tip mechanical field and crack propagation path are investigated. In this paper, an extended finite element method for studying the crack propagation behavior of dissimilar metal welded joints under elastoplastic conditions is proposed, which is of great significance to ensure the safe operation of nuclear power welded joints under high temperature and high pressure water conditions.
【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】：2017
【分類號】：TG407

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本文編號：1912288