On the collapse propagation of thick-walled dented submarine pipelines

Subsea pipelines are susceptible to structural instabilities. Particularly in deep waters, where pressures are very high, collapse is the most critical instability and can be rapidly propagated, damaging kilometers of the pipeline, with catastrophic impacts. In addition to high pressures, any damage that may occur due to impact, excessive bending, corrosion, and other causes during pipeline transport, installation and operation, can dramatically reduce the collapse and propagation pressure of the structure. Static buckling of pipelines under external pressure is a well-established subject in the literature and classical theories such as Timoshenko's provide reasonable estimates of the buckling threshold under some conditions. The accuracy of these predictions is particularly good for long, thin tubes, but when it comes to damaged thick-walled pipelines, there is a gap of knowledge and a lack of information regarding the post-buckling behavior of such pipes. Thus, this work aims to present a comprehensive study on the collapse propagation of thick-walled dented submarine pipelines based on experimental analysis, numerical models and a parametric study in order to cover several scenarios of interest.