Effects of the UOE/UOC pipe manufacturing processes on pipe collapse pressure
Effects of the UOE/UOC pipe manufacturing processes on pipe collapse pressure
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DOI：
10.1016/j.ijmecsci.2006.10.001
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发表时间：
2007-05-01
影响因子：
7.3
通讯作者：
Yun, H. D.
中科院分区：
文献类型：
--
作者：
Herynk, M. D.;Kyriakides, S.;Yun, H. D.
海上应用中使用的大直径管道通常通过 UOE 工艺由冷成型板制造。将板沿其边缘卷曲，形成 U 形，然后在两个半圆形模具之间压制成 O 形。管道被焊接封闭，然后沿周向扩张以获得高度圆形的形状。塌陷实验表明，这些步骤，尤其是最终的膨胀，会降低管道的机械性能，并导致其塌陷压力降低 30% 以上。在本研究中，使用二维有限元模型对 UOE 成形过程进行了数值模拟。该模型可以评估每个成型步骤的压制参数对管道最终几何形状和机械性能的影响。最后一步是模拟外部压力下的管道塌陷，以量化成形变量对其性能的影响。这些变量的例子包括成形模具的半径、所选模具的位移、O 形步骤中的压缩应变、膨胀应变等。我们对这个问题进行了广泛的参数研究，通过这些研究，建立了优化工艺以改善塌陷性能的方法。例如，我们发现最佳塌陷压力需要在管道形状（椭圆度）和材料降解之间进行权衡。一般来说，O 应变的增加和膨胀应变的减少会提高塌陷压力。用压缩代替膨胀不仅可以缓解 UOE 塌陷压力下降，而且可以显着提高塌陷性能。 (c) 2006 Elsevier Ltd. 保留所有权利。
Large-diameter pipes used in offshore applications are commonly manufactured by cold-forming plates through the UOE process. The plate is crimped along its edges, formed into a U-shape and then pressed into an O-shape between two semicircular dies. The pipe is welded closed and then circumferentially expanded to obtain a highly circular shape. Collapse experiments have demonstrated that these steps, especially the final exparsion, degrade the mechanical properties of the pipe and result in a reduction in its collapse pressure upwards of 30%. In this study the UOE forming process has been modeled numerically using a 2-D finite element model. The model can assess the effects of press parameters of each forming step on the final geometry and mechanical properties of the pipe. The final step involves simulation of pipe collapse under external pressure in order to quantify the effect of the forming variables on its performance. Examples of these variables are the radii of the forming dies, the chosen displacements of the dies, the compression strain in the O-step, the expansion strain, etc. An extensive parametric study of the problem has been conducted, through which ways of optimizing the process for improved collapse performance have been established. For example, it was found that optimum collapse pressure requires a tradeoff between pipe shape (ovality) and material degradation. Generally, increase in the O-strain and decrease in the expansion strain improve the collapse pressure. Substituting the expansion with compression can not only alleviate the UOE collapse pressure degradation but can result in significant increases in collapse performance. (c) 2006 Elsevier Ltd. All rights reserved.