Mehdi Saeed Kiasat - Department of Marine Technology, Amirkabir University of Technology
Hamze Arman - MSc Offshore Engineering, Iranian Classification Society

The application of filament-wound composite pipes for the marine transmission of natural gas is to be studied in thiswork. Pipelines resting on the seabed are subjected to the fluid loading resulted from waves and steady currents. Thenatural gas extracted from the South Pars reservoir is at a high pressure of 132 bars in the entrance of the pipeline. Onbottom lateral and vertical stability assessment of the pipeline is performed. Also, the spanning of the pipeline over an appreciable distance due to the lack of the contact between the pipeline and a rough seabed is taken into account in the finite element modeling. A laminated composite pipe is analyzed under the combination of the drag, lift and inertial fluid loads, internal and external pressures, and gravity. These loads are incrementally applied to the pipe in order to be able to study the progressive failure of the layers of the laminated pipe. Finally, the stacking sequence of the unidirectional plies for the pipe is optimized in order to safely carry all hydrodynamic environmental loads

Composite pipe, Natural gas transmission, On-bottom stability, Free-span analysis