On the arresting efficiency of CFRP-winding buckle arrestors for subsea pipelines

Abstract

Carbon fiber reinforced polymer (CFRP)-winding buckle arrestor, conceived as a new type of arresting device, is capable of locally enhancing the circumferential stiffness of pipes to provide an obstacle to a propagating buckle. This type of arrestor is composed of CFRP and adhesive layers, which are wrapped around the pipe for a number of turns. In the present study, collapse experiments were conducted on four groups of small-scale pipes in a hyperbaric chamber, and the effect of CFRP layer number, arrestor length, and CFRP sheet thickness on the crossover pressure was examined. The crossover mode of relatively thinner arrestor cases was found dominated by a flattening mode, whereas the collapse mode changed into a singly symmetric U-shape mode when the arrestor became thicker. A non-linear finite element (FE) model was developed to simulate the event of the CFRP-winding arrestor crossed by the propagating buckle, where a reasonable agreement was achieved between the experiments and numerical predictions. Then, parametric analyses were numerically performed, based on which an empirical formula was proposed for the crossover pressure of CFRP-winding arrestors exhibiting the flattening mode. In addition, comparative studies with the conventional arrestor further confirmed the viability of adopting the CFRP-winding arrestor.