Toscano Rita G., Mantovano Luciano O., Amenta Pablo M., Charreau Roberto F., Johnson Daniel H., Assanelli Andrea P., Dvorkin Eduardo N. Collapse arrestors for deepwater pipelines Cross-over mechanisms

Computers & Structures, Volume 86, Issues 7–8, April 2008. — p. 728–743.Using finite element models it is possible to determine the cross-over ex- ternal pressure of different pipeline arrestor designs. In this paper these fi- nite element models are discussed and validated by comparing their results with experimental determinations. The flipping and flattening cross-over mechanisms, that were previously described in the literature, are consid- ered in the experimental validation of the numerical models.In this paper we focus on the analysis of the collapse and post-collapse behavior of pipelines reinforced with buckle arrestors: we develop finite element models to analyze the collapse, collapse propagation and cross-over pressures of reinforced pipes and we present an experimental validation of the models. In particular we consider the case of welded integral arrestors. Two different integral buckle arrestor cross-over mechanisms were identified in the literature: flattening and flipping. The occurrence of either cross-over mechanism is determined by the geometry of the pipes and of the arrestors [8]. In the second section of this paper we describe our experimental facilities and the laboratory tests that we performed to determine, for different pipe - arrestor geometries, the collapse, propagation and cross-over pressures. In the third section we describe the finite element models that we developed to simulate the collapse tests and in the fourth section we compare the experimental and finite element results in order to validate the last ones. Few experimental results are available in the literature for the cross-over of integral ring buckle arrestors under external pressure, on large diameter car- bon steel pipes [8]-[14]. Therefore, this paper adds to the available technical literature in a range where more information can be useful.