Riser-seabed interaction in the touchdown zone using fibre optic sensing in a geotechnical centrifuge
Fatigue damage of Steel Catenary Risers (SCRs) is typically greatest within the touchdown zone (TDZ), where cyclic interaction of the riser with the seabed results in complex changes of soil properties and potential changes in riser curvature, especially if a trench forms. This complex phenomenon...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Proceeding |
| Language: | en |
| Published: |
2022
|
| Subjects: | |
| Online Access: | http://ir.unimas.my/id/eprint/45977/1/Riser-seabed%20interaction%20in%20the%20touchdown%20zone%20-%20Copy.pdf http://ir.unimas.my/id/eprint/45977/ https://www.issmge.org/publications/publication/riser-seabed-interaction-in-the-touchdown-zone-using-fibre-optic-sensing-in-a-geotechnical-centrifuge |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Fatigue damage of Steel Catenary Risers (SCRs) is typically greatest within the touchdown zone (TDZ),
where cyclic interaction of the riser with the seabed results in complex changes of soil properties and potential changes
in riser curvature, especially if a trench forms. This complex phenomenon has prompted researchers to pursue
improved understanding of SCR behaviour in the TDZ, to enhance design life assessment and overall design. Past
studies have shown that modelling a section of the riser around the TDZ can satisfactorily capture touchdown behaviour.
However, the use of conventional strain gauges may result in unwanted stiffening of the model, while also limiting the
number of data points at which strain is measured. This paper presents centrifuge tests performed using a SCR model
instrumented with a novel fibre optic sensing system. The system comprises three Fibre Braggs Grating fibre strands
along the SCR model, separated circumferentially by 120º in cross section, with each strand measuring over 350 points
of strain. Realistic sea states were scaled and translated to the cut-off point on the riser above an elastic (dummy)
seabed, with surge, heave and sway motions simultaneously applied using three degrees of actuation. The riser-seabed
interaction along the TDZ was successfully captured, with experimental results validated against finite element
analyses. Following the success of this campaign, the model is now being used to explore response on clay seabed
samples, which will further advance understanding of SCR behaviour at the TDZ. |
|---|