Buckle propagation is a relevant design criterion for deepwater offshore pipelines. Imposed by external impact or local bending, e.g. during laying, a local buckle can be initiated, thereby decreasing the collapse strength of the pipeline. As a result of the high ambient external pressure, the buckle can start to propagate. Several design criteria for buckle propagation exist. This paper compares different design criteria with numerical results to obtain an impression of the levels of conservatism applied in the various codes. In most design cases, it is not suitable to avoid buckle propagation by using an increased wall thickness over the entire pipeline. Therefore, buckle arrestors are installed to stop the propagation. The common technical solution is to install sections of thicker pipeline, which requires that the buckle arrestor wall thickness and the length of the buckle arrestor have to be determined during design. A distinction is drawn between short and long buckle arrestors. Both cases are considered here. The design of the buckle arrestor can be carried out by using well-known criteria, such as the criteria developed by Kyriakides, Langner or Torselletti et al. These criteria are compared with experimental data. Numerical calculations are carried out and the results are compared with the design criteria. The validation of the numerical results with respect to experimental data shows acceptable deviations, especially if we take into consideration that several deviations are a consequence of unknown material dependences (concerning the nonlinear behaviour, statistical data, like mean or standard deviation); Missing measurement tolerances (very few papers about buckling measurements consider such essential aspects). In accordance with this experience, it seems generally possible to calculate and design buckle arrestors by means of finite element investigations. Taking into consideration the increased age of installed deep-water pipelines, it should be mentioned that little knowledge is available on buckling where corrosion flaws are involved
Comparison of numerical results and design criteria for buckle propagation and buckle arrestor design
Vergleich der numerischen Ergebnissen und Entwurfskriterien für die Beulenausbreitung und Entwurf eines Buckle-Arrestors
2006
11 Seiten, 14 Bilder, 7 Tabellen, 17 Quellen
Conference paper
English
On the arresting performance of welded-ring buckle arrestor for subsea pipelines
Taylor & Francis Verlag | 2020
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