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The pipe bends downward near the surface of the sea and in the opposite direction near the seabed during this so-called “S-Lay” operation. Pipe cross section ovalization during “Brazier” bending, elastic-plastic material behavior, possible local buckling of the pipe on the compression sides where bending occurs and the effect of external hydrostatic pressure must all be accounted for in an analysis of the pipe.
FROM:
Peng Xie (1) and Qian Yue (2)
(1) Engineering and Technology Department, COOEC Subsea Technology Co., LTD Shenzhen, Guangdong, China
(2) State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology Dalian, Liaoning, China
“Onboard monitoring system of overbend pipe during deepwater S-lay installation”, International Journal of Offshore and Polar Engineering, Vol. 27, No. 2, pp 216-221, June 2017
https://doi.org/10.17736/ijope.2017.jc667
ABSTRACT: In S-lay operations, the pipeline passes over the stinger and is laid on the seabed after welding and nondestructive tests. The high combined loadings of axial tension, bending moment, roller reaction force, and the pipelay vessel motion may result in plastic deformation in the pipeline, which is difficult to accurately quantify. A real-time onboard monitoring system is recommended to guarantee the safety of the pipelaying process in challenging projects that include very large strain in the pipeline. However, most of the current onboard monitoring systems focus on the submerged section and sagbend section of the pipeline. The overbend section is ignored because of the uncertainty resulting from the combined loadings and the dynamic process during the pipe passing over the stinger. The present paper proposes a novel online monitoring method based on the roller reaction force measurement, which can monitor the dynamic overbend pipe strain fluctuations in real time. Relevant analytical equations in the model are first derived, then a large-scale hybrid model test and numerical simulation are carried out to verify the proposed monitoring system.
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