Abstract Controlled lateral buckling is triggered by distributed buoyancy section at predesigned sites to release the axial force induced by high temperature and high pressure in subsea pipelines. Due to the larger diameter and smaller submerged weight of distributed buoyancy section, compared to the normal pipe section, imperfections are more easily introduced at the location of distributed buoyancy section. In this study, an analytical model is proposed to simulate lateral buckling triggered by a distributed buoyancy section for an imperfect subsea pipeline, which is validated by test data. Semi-analytical solutions are derived. First, snap-through buckling behaviour is discussed. Then the influence of initial imperfections on buckled configurations, post-buckling behaviour, displacement amplitude and maximum stress is discussed in detail. The results show that there is no snap-through phenomenon for large amplitude of initial imperfections, which appears only when the amplitude of imperfection is small enough. The displacement amplitude increases with the amplitude of initial imperfections, and it first increases and then decreases with wavelength of initial imperfection. Compared to a perfect pipeline, the maximum stress amplifies for relative small wavelength of initial imperfections. Therefore, a large enough wavelength of initial imperfection should be introduced.

中文翻译：

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分布式浮力截面引发海底管道横向热屈曲缺陷研究

摘要 受控侧向屈曲是由预先设计好的位置分布的浮力段触发，以释放海底管道高温高压引起的轴向力。由于分布式浮力段的直径较大，水下重量较小，与普通管段相比，分布浮力段位置更容易引入缺陷。在这项研究中，提出了一种分析模型来模拟由分布式浮力部分触发的不完善海底管道的横向屈曲，并通过测试数据进行验证。推导出半解析解。首先，讨论快速屈曲行为。然后详细讨论了初始缺陷对屈曲构型、屈曲后行为、位移幅度和最大应力的影响。结果表明，对于较大的初始缺陷幅度，不存在快速穿透现象，只有在缺陷幅度足够小时才会出现这种现象。位移幅值随初始缺陷的幅值而增加，随初始缺陷的波长先增大后减小。与完美的管道相比，最大应力会因初始缺陷的相对较小波长而放大。因此，应引入足够大的初始缺陷波长。它随着初始缺陷的波长先增大后减小。与完美的管道相比，最大应力会因初始缺陷的相对较小波长而放大。因此，应引入足够大的初始缺陷波长。它随着初始缺陷的波长先增大后减小。与完美的管道相比，最大应力会因初始缺陷的相对较小波长而放大。因此，应引入足够大的初始缺陷波长。