\r余建星^{1, 2}，李牧之^{1, 2}，余 杨^{1, 2}，韩梦雪^{1, 2}，李 杨^{1, 2}，于佳晖\r^{1, 2}\r
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AuthorsHTML:\r余建星^{1, 2}，李牧之^{1, 2}，余 杨^{1, 2}，韩梦雪^{1, 2}，李 杨^{1, 2}，于佳晖\r^{1, 2}\r
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AuthorsListE:\rYu Jianxing^{1, 2}，Li Muzhi^{1, 2}，Yu Yang^{1, 2}，Han Mengxue^{1, 2}，Li Yang^{1, 2}，Yu Jiahui\r^{1, 2}\r
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AuthorsHTMLE:\rYu Jianxing^{1, 2}，Li Muzhi^{1, 2}，Yu Yang^{1, 2}，Han Mengxue^{1, 2}，Li Yang^{1, 2}，Yu Jiahui\r^{1, 2}\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\r
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Unit_EngLish:\r1. State Key Laboratory of Hydraulic Engineering Simulation and Safety，Tianjin University，Tianjin 300072，China；
2. Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration，Shanghai 200240，China\r
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Abstract_Chinese:\r\r针对含初始椭圆度缺陷的海底管道在弯矩和水压联合作用下的屈曲破坏问题，基于薄壁假定，选择能够描述管道应变和曲率随位移变化的几何方程，采用流动理论建立应力增量与应变增量之间的关系，采用三角级数对位移函数进行离散，列出管道的初始椭圆度缺陷的形式，最终基于虚功原理建立了复杂载荷作用下管道的理论模型．通过控制轴向曲率和外部水压的增量及加载顺序，在\rMATLAB\r中对由虚功原理推导出的非线性方程组进行数值求解，从而得到管道在不同加载路径下的极限承载力．同时运用有限元计算软件，在合理控制了刚体位移和边界条件的基础上实现对弯矩和水压载荷的分步加载，得到了弯矩和水压联合作用下的管道有限元模型，计算管道的承载性能并与理论模型进行对比，验证了理论模型的准确性．之后，以管道缺陷截面在压溃瞬间的椭圆度为计算指标，采用有限元方法分别计算不同加载路径下的管道破坏形式，从而对弯矩和水压联合作用下的管道压溃破坏机理进行探究．研究结果表明：弯矩载荷对管道承压能力的削弱作用主要体现在弯矩对\rMises\r应力和截面椭圆度的增大两个方面，在弯矩载荷较小时，椭圆度的影响起主要作用；外压—弯矩加载路径下管道的承载性能较低的原因是缺陷截面在压溃瞬间的椭圆度较弯矩—外压加载路径大．\r\r
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Abstract_English:\r\rIn order to study the buckling collapse of subsea pipelines with an initial ovality imperfection under the combined action of bending moment and external pressure\r，\rbased on a thin-walled assumption\r，\rkinematical relationships describing the variation of strain and curvature of the pipeline with displacements were chosen\r．\rThe relationship between stress increment and strain increment was established by flow theory\r，\rthe displacement functions were discretized by trigonometric series\r．\rThe form of initial ovality defect of the pipeline was listed\r．\rFinally\r，\ra theoretical model of the pipeline under a complex load was established based on the principle of virtual work\r．\rBy controlling the increment of axial curvature\r，\rthe increment of external water pressure\r，\rand loading sequence\r，\rthe nonlinear equations derived from the principle of virtual work were solved numerically in MATLAB\r．\rThe ultimate bearing capacity of the pipeline under different loading paths was obtained\r．\rMeanwhile\r，\rfinite element software was used to simulate the pipeline model under reasonable control of rigid body displacement and boundary conditions\r．\rThe bending moment and external pressure were imposed step-by-step\r．\rResults of the bearing capacity of the pipeline were compared with the theoretical model\r，\rwhich verified the accuracy of the model\r．\rIn addition\r，\rtaking the ovality of the pipeline’s defective section at the collapsing instant as an index\r，\rthe failure modes of the pipeline under different loading paths were calculated by finite element method\r．\rThe collapsing failure mechanism of the pipeline under the combined action of bending moment and external pressure was explored\r．\rResults showed that the weakening effect of the moment load on the pressure bearing capacity of the pipeline is reflected in the increase of Mises stress and the ovality of the defective section\r．\rThe ovality plays a major role when the bending moment is small\r．\rThe reason for the low load-carrying capacity of the pipeline under a pressure-moment loading path is that the ovality of the defective section at the moment of collapse is larger than that of the moment-pressure loading path\r．\r\r
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Keyword_Chinese:海底管道；复杂载荷；虚功原理\r

Keywords_English:subsea pipeline；complex load；principle of virtual work\r


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