Collapse failure of textured subsea pipeline under external pressure; numerical and parametric study

The concept of pseudo-cylindrical concave polyhedral (PCCP) shell is adopted for subsea pipeline applications and termed as textured pipe. In this study, the collapse responses of proposed textured pipelines subjected to external pressure are studied experimentally and numerically and are compared to those of the conventional pipes. First, hyperbaric chamber test results of 3D-printed textured and conventional pipes are presented. The experimental results showed that the textured concept can provide a significant delay in collapse failure compared to the corresponding conventional pipe. Also, the average collapse pressure of textured pipes was found to be 80% greater than the conventional pipe, with same D/t ratio. By using the validated FE model, different collapse responses with practical range of D/t ratio between 13 and 50 are discussed, and a compre-hensive parametric study is conducted. Finally, a new collapse pressure formula including the geometric and material parameters and the ovality is presented to predict the collapse pressure of the textured pipe. The study showed that the collapse pressure of the textured pipe is much less sensitive to initial ovality compared to corresponding conventional pipe and a textured pipe with alpha <= 45 and 5 <= N <= 8, can offer an optimum resilience to external pressure.

Automated summary

The study introduced the concept of textured pipes for subsea pipeline applications and compared their collapse responses to conventional pipes under external pressure. Results showed that textured pipes have a significantly delayed collapse failure and higher collapse pressure compared to conventional pipes. By conducting experimental and numerical research, it was found that textured pipes exhibit greater resistance to external pressure and higher collapse pressure, making them a more resilient option for subsea pipeline applications.