深水钢悬链立管管土相互作用及疲劳分析

发布时间：2018-10-26 17:20

【摘要】：大量的研究以及工程实地调查表明,钢悬链立管触地区疲劳破坏较为严重,是影响立管设计的关键因素之一。在实际工程项目中,通常采用较保守方法,即将管土之间的相互作用用线性弹簧来模拟。更精确数值模拟需要建立一个可以更真实描述管土相互作用的非线性模型。本文应用ABAQUS显示动态分析对管土相互作用过程进行模拟,获得了与NGI实验结果一致的管土相互作用的骨架曲线以及单次循环位移下的力与位移的曲线,并讨论了土体粘聚力,摩擦角,立管外径以及立管壁厚对管土相互作用的影响。基于垂向数值管土相互作用曲线模型,及横向管土相互作用库伦摩擦模型,对非线性管土相互作用单元进行二次开发,建立了钢悬链立管的非线性动态分析整体模型,研究立管触地区的位形,受力情况以及疲劳寿命,并进行了参数影响规律分析。分析结果表明,粘聚力,摩擦角以及立管外径都对管土相互作用影响显著,随着这些参数的增加,立管相同位移下的受到的土体反力有所增加;触地区的埋深受土壤参数和立管设计参数的影响,平台的运动对触地区的位置以及范围有较大影响;土壤粘聚力、摩擦角以及立管外径的增大会导致疲劳损伤的增加,而立管壁厚的增加对立管的疲劳有利;平台的三个方向的运动中,垂荡对立管触地区的影响最大,此方向的循环位移导致立管触地区的疲劳损伤最严重,并且更容易导致触地区的扩大,增加大疲劳损伤的范围。
[Abstract]:A large number of researches and engineering investigations show that the fatigue damage of steel catenary risers is serious and is one of the key factors affecting the design of risers. In practical engineering projects, a conservative method is usually used, in which the interaction between pipe and soil is simulated by linear spring. More accurate numerical simulation needs to establish a nonlinear model which can describe the interaction between pipe and soil more realistically. In this paper, the tube-soil interaction process is simulated by using ABAQUS display dynamic analysis. The skeleton curve of pipe-soil interaction and the curve of force and displacement under single cyclic displacement are obtained, which are consistent with the results of NGI experiment, and the cohesive force of soil is discussed. The influence of friction angle, diameter of riser and wall thickness of riser on tube-soil interaction. Based on the vertical numerical pipe-soil interaction curve model and the transverse tube-soil interaction Coulomb friction model, the nonlinear dynamic analysis model of steel catenary riser is established by secondary development of nonlinear tube-soil interaction unit. The configuration, stress and fatigue life of the riser in the contact area are studied, and the influence of the parameters on the fatigue life is analyzed. The results show that the cohesive force, friction angle and the diameter of riser have a significant effect on the pipe-soil interaction. With the increase of these parameters, the soil reaction under the same displacement of riser increases. The embankment of the contact area is deeply influenced by the soil parameters and the design parameters of the riser, and the movement of the platform has a great influence on the location and range of the contact area. The increase of soil cohesion, friction angle and the outer diameter of riser will lead to the increase of fatigue damage, but the increase of wall thickness of the riser is beneficial to the fatigue of the pipe. In the motion of three directions of the platform, the pendulum has the greatest influence on the contact area of the pipe, and the cyclic displacement in this direction leads to the most serious fatigue damage in the contact area of the riser, and it is more likely to lead to the expansion of the contact area and increase the range of the large fatigue damage.
【学位授予单位】：哈尔滨工程大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P756.2

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