Stress analysis of the subsea dynamic riser baseprocess piping

Abstract

Thesubsea dynamic riser base (SDRB) is an important piece of equipment for the floating production platform mooring system. One end is connected to the rigid pipeline, carrying a rigid pipeline thermal expansion load and the other end is connected to a flexible riser, carrying the dynamic load of the flexible riser, so its function is a transition connection between the flexible riser and the rigid pipeline which fixes the flexible riser on the seabed. On the other hand, as a typical subsea product, the design will satisfy the requirements of the standards for subsea products. By studying the stress analysisphilosophy of the topside piping and subsea pipeline, a physical model and procedure for piping stress analysis of the SDRB have been established. The conditions of the adverse design load have been considered, and a combination of the static load from the rigid pipeline and the dynamic load flexibility has also been optimized. And a comparative analysis between the AMSE, DNV and API standards for piping stress with the checking rules has been done. Because the SDRB belongs to the subsea pipeline terminal product, the use of DNV standards to check its process piping stress is recommended. Finally, the process piping stress of the SDRB has been calculated, and the results show that the jacket pipe and the carrier pipe stress of the SDRB process piping satisfy the DNV standards as a whole.The bulkhead cannot be accurately simulated by the AutoPIPE software which uses the FEA software ANSYS in the detailed analysis, but the checking results will still meet the requirements of the DNV standards.

Keywords

subsea product design / subsea dynamic riser base(SDRB) / process piping stress analysis / flexible riser / rigid pipeline

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