Abstract

Free span assessments of subsea pipelines are required to predict a pipeline free span's fatigue life under the influence of the vortex shedding phenomenon. Free span responses to vortex shedding are usually predicted by using a modal response technique. This paper gives details of a finite element development by Subsea 7 for free span assessments in both the frequency and time domains and demonstrates that, in the time domain, it is possible to capture beneficial effects such as a non-linear foundation stiffness, energy dissipation by friction and intermittent touch-down which would otherwise be lost.

Keywords:
frequency, time domain, span, energy dissipation, empty condition, dnv, offshore pipeline, dissipation, midstream oil & gas, calibration
Subjects:
Pipelines, Flowlines and Risers, Offshore pipelines
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2014. International Society of Offshore and Polar Engineers
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