The cross-over mechanisms of integral buckle arrestors for offshore pipelines

• Published in: Applied ocean research 2017-09, Vol.67, p.236-247
• Main Authors: Yu, Jian-xing, Duan, Jing-hui, Sun, Zhen-zhou, Yu, Yang, Wu, Meng-ning
• Format: Article
• Language: English
• Subjects: Buckling propagation; Cross-over mechanisms; Deepwater; Finite element analysis; Integral buckle arrestor; Modes; Numerical analysis; Offshore; Offshore oil exploration & development; Pipelines; Pipes; Studies; Submarine pipelines; Submarines
• ISSN: 0141-1187; 1879-1549
• DOI: 10.1016/j.apor.2017.07.016

•A parametric study of experiments and FE models is made to explain a new experimental phenomenon.•The initial local ovality of downstream pipes highly impacts crossover modes.•The FE models are reliable to simulate the experimental process accurately.•Through physical experiments and numerical simulations, the switch point of two modes is calculated. Local buckling of submarine pipelines is unavoidable under extreme conditions and it can propagate along the pipeline. Thus, arrestors are installed in a periodic placement along the pipeline to limit the extent of catastrophic collapse between two adjacent arrestors. Generally, the integral buckle arrestors are crossed by two modes: the flattening mode and the flipping mode. This paper focuses on the cross-over mechanisms of arrestors by analyzing results from experiments and numerical simulations. Fifteen groups of full-scale and reduced-scale physical experiments are conducted to investigate the effect of local ovality of the downstream pipes on the arrestor performance. Furthermore, an extensive parametric study of cross-over modes of arrestors is performed by FE models to supplement the experimental results. It is found that the local ovality of the downstream pipes impacts the cross-over modes of integral buckle arrestors, which is more likely to deform by ovalization in the same sense as the local ovality. On the other hand, a new formula involving the major geometric and material characteristics of pipes and arrestors is proposed to estimate the flattening mode and the flipping mode of arrestors when the downstream pipes are intact. And the switch point of the two cross-over modes is 0.265.