\r余建星^{1, 2}，李修波^{1, 2}，谭玉娜^{1, 2}，金成行^{1, 2}，冯志强³，韩翔希³，符 妃\r³\r
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AuthorsHTML:\r余建星^{1, 2}，李修波^{1, 2}，谭玉娜^{1, 2}，金成行^{1, 2}，冯志强³，韩翔希³，符 妃\r³\r
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AuthorsListE:\rYu Jianxing^{1, 2}，Li Xiubo^{1, 2}，Tan Yuna^{1, 2}，Jin Chenghang^{1, 2}，Feng Zhiqiang³，Han Xiangxi³，Fu Fei\r³\r
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AuthorsHTMLE:\rYu Jianxing^{1, 2}，Li Xiubo^{1, 2}，Tan Yuna^{1, 2}，Jin Chenghang^{1, 2}，Feng Zhiqiang³，Han Xiangxi³，Fu Fei\r³\r
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Unit:\r1. 天津大学水利工程仿真与安全国家重点实验室，天津 300072；
2. 高新船舶与深海开发装备协同创新中心，上海 200240；
3. 钦州学院机械与船舶海洋工程学院，钦州 535011\r
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Unit_EngLish:\r1. State Kay Laboratory of Hydraulic Engineering Simulation and Safety，School of Civil Engineering，Tianjin University，Tianjin 300072，China；
2. Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration，Shanghai 200240，China；
3. Institute of Mechanical and Marine Engineering，Qinzhou University，Qinzhou 535011，China\r
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Abstract_Chinese:\r针对在役的海底管道遭受腐蚀疲劳损伤时其管道表面出现点蚀坑问题，应力强度因子成为衡量蚀坑向裂纹转变的临界条件之一．断裂力学的腐蚀疲劳寿命分析的基础是腐蚀疲劳裂纹扩展，裂纹的不稳定扩展又由应力强度因子来判别．因此，在腐蚀疲劳破坏中，将点蚀坑和应力强度因子结合起来研究变得尤为重要．基于应力集中是导致裂纹萌生的主导因素，建立了双参数蚀坑模型，合理地解释了腐蚀疲劳裂纹在蚀坑处萌生位置差异的现象．在管道内流体压力的作用下，管道外表面轴向I 型裂纹在环向应力的作用下成为最为危险的一种裂纹型式．基于线弹性断裂力学，利用ABAQUS 软件，在管道内压作用下，采用二维模型，对管道表面的轴向I 型蚀坑＋裂纹的应力强度因子展开了分析．结果显示，蚀坑对裂纹应力强度因子的取值产生明显影响，可显著降低裂纹扩展的门槛值．进一步采用三维模型，利用扩展有限元法，对影响轴向I 型蚀坑-裂纹应力强度因子的蚀坑参数开展了敏感性分析．结果显示，蚀坑参数的不同，对蚀坑-裂纹应力强度因子、裂纹形状因子的影响趋势各异．随着蚀坑参数深径比α、深度d 的增大，蚀坑-裂纹应力强度因子的取值也逐渐变大；蚀坑参数深径比α、深度d 对形状因子F 取值的影响存在一定的区间效应．\r
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Abstract_English:\rThis study is aimed to address the problem of pits occurring on the surface of an in-service submarine pipeline subjected to corrosion fatigue and the subsequent damage caused. The stress intensity factor is one of the critical conditions for measuring the transition from pit to crack. The basis for corrosion fatigue life analysis with regard to the fracture mechanics is corrosion fatigue crack propagation. The unstable propagation of the crack is determined by the stress intensity factor. Therefore，it is imperative to combine the pit and crack stress intensity factors in terms of research on corrosion fatigue damage. On the basis of the idea that stress concentration is the main factor leading to the emanation of cracks，a two-parameter pit model，which can reasonably explain the phenomenon that cracks emanate from different locations depending where the pit is established. Under the action of fluid pressure in the pipeline，the axial I-shaped crack becomes the most dangerous crack type hoop stress. According to the concept of linear fracture mechanics，the stress intensity factor of the pit with the axial I-shaped crack on the surface of the pipeline under the hoop stress by 2D model was analyzed using the ABAQUS software. The results indicated that the pit has a significant effect on the value of the crack stress intensity factor，which can significantly reduce the threshold of crack propagation. Sensitivity analysis of the pit parameters affecting the stress intensity factor of the axial I-shaped pit-crack in the 3D model was conducted using the extended finite element method. The results indicated that the influence of the pit parameters on the pit-crack stress intensity factor and crack shape factor has different trends. With the increase in the depth-diameter ratio α and depth d of the pit parameters，the value of the pit-crack stress intensity factor also increased. A certain interval effect on the influence of the depth-diameter ratio α and depth d on the value of the shape factor F was observed.\r
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Keyword_Chinese:双参数蚀坑；裂纹；海底管道；应力强度因子\r

Keywords_English:two-parameter pit；crack；submarine pipeline；stress intensity factor\r


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