Experimental and finite element study on lateral global buckling of pipe-in-pipe structure by active control method. (November 2019)

• Record Type: Journal Article
• Authors: Zhang, Zechao; Yu, Jinghai; Liu, Hongbo; Chen, Zhihua
• Is Part Of: Applied ocean research. Volume 92(2020)
• Publication Date: 2019-11
• Subjects: Sleeper method -- Initial imperfections -- pipe-in-pipe (PIP) structure -- Global buckling -- Active control method; Ocean engineering -- Periodicals; 620.416205
• DOI: 10.1016/j.apor.2019.101917
• Languages: English
• ISSNs: 0141-1187

Abstract

Highlights: On the basis of the experimental study on the global buckling of the sleeper–snake lay PIP system, the effects of different imperfection wavelengths and amplitudes on the global buckling of the PIP system were analyzed. A numerical analysis model of global buckling was established, and the influences of different parameters on global buckling response were investigated. The accuracy of the numerical model was verified through experiments. The calculation equation of the global critical horizontal lateral force of this type of PIP system was derived based on the experimental results and then verified. Abstract: Offshore oil and gas exploration are gradually heading toward the deep sea and even the ultra-deep sea. According, the working temperature and pressure intensity of subsea oil and gas pipelines have increased by a considerable degree. This situation is accompanied by the global buckling problem in deep sea pipelines, which has become increasingly common. Meanwhile, ordinary single-layer pipelines cannot last for a long time under harsh deep-sea working conditions. Thus, multilayer pipelines, such as the pipe-in-pipe (PIP) structure and bundled pipelines, have gradually become top choices. However, the global buckling mechanisms of these multilayer pipelines are more complicated than those of single-layer pipelines. The sleeper–snake lay pipeline, which is an active control method for global buckling, was used in this study. The change and development laws of global buckling in a PIP structure at different wavelengths and amplitudes were determined through an experimental study. A dynamic solution method that considers artificial damping was adopted to establish finite element global buckling models of a PIP structure with initial imperfections. The effects of various factors, such as pipeline laying shape, sleeper–pipe function, and seabed–pipe function, on global buckling were analyzed. By the result of finite element method analysis, the initial imperfection, and sleeper–pipeline friction were determined to be the key factors that influenced critical pipeline buckling force. Accordingly, a reference for the design of PIP structures is presented.