ABSTRACT

Slender systems in which the length dominates over the other dimensions are an integral part of offshore systems. Modelling of such systems takes into account bending, sometimes torsional, and more rarely longitudinal deformations. The paper presents a new formulation of the segment method, in which the elongation of a slender link is considered; it is also possible to restrict analysis to one selected deformation while neglecting the others, which results in a very high computational efficiency. The models take into account the impact of the environment and the flows inside risers. Validation is carried out by comparing the simulation results with those presented by other researchers. The method is then applied in the solution of dynamic optimisation problems concerning the re-entry process, which includes disconnecting the riser from the wellhead and moving the platform with the riser. Due to consideration of sea currents, this task is a spatial problem.

摘要

长度超过其他尺寸的细长系统是海上系统的组成部分。这种系统的建模考虑了弯曲，有时是扭转，很少考虑纵向变形。本文提出了一种新的分段法公式，其中考虑了细长链节的伸长率；也可以将分析限制在一个选定的变形而忽略其他变形，这会产生非常高的计算效率。这些模型考虑了环境的影响和立管内的流量。通过将模拟结果与其他研究人员提供的结果进行比较来进行验证。然后将该方法应用于解决有关再入过程的动态优化问题，这包括将立管从井口断开，并用立管移动平台。由于考虑到海流，这项任务是一个空间问题。