Numerical analyses of underwater pipe sections under falling objects

Abstract

Underwater and land pipelines are generally modelled under the environmental loads. In addition to these mentioned loads, pipelines are subjected to destructive sudden loads due to accidental drops, ship anchors, rock falls, trawlers fishing and military attacks. In this study, numeric analysis of the same pipe section has been carried out according to the sudden loads caused by falling objects both underwater and on land. Abaqus finite elements analysis software is used in the analysis. While the interaction of pipe-falling object is modelled in the analysis of the pipeline on land, the interaction of pipe-falling object-water is modelled in the underwater pipeline. Bidirectional fluid-structure interaction (FSI) analysis is utilized in the water-pipe-falling object interaction modelling. A fully nonlinear free surface simulation is performed by Coupled Eulerian Lagrangian (CEL) technique in the FSI analysis. Impact parameters such as accelerations, velocities, displacements and impact forces, are determined for both land and underwater pipe sections at the end. Thus, while determining the effect of water on the impact behaviour, the free surface movement of the water in the course of impact is also obtained.