Disconnected Mode |
 
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Disconnected Mode |
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Results from the disconnected mode analysis are presented in the Comparing Tension along Riser figure (below) to the Drift-Off LFJ Angle figure. The Drift-Off LFJ Angle and Horizontal Motion along Riser figure (below) are from the static restart with current, and plot respectively horizontal displacement and von Mises stress. The displacement plot shows that the LMRP moves approximately 6.7 ft under the action of the 100-year current. The von Mises stresses are again acceptable.
Horizontal Motion along Riser
Static Von Mises Stress
The 'Static Von Mises Stress' figure compares timetraces of vessel pitch and the rotation below the UFJ from the time domain solution. The pitch varies between –7.5 degrees and +7.5 degrees, but the corresponding rotations below the UFJ are much less, varying between –2.5 degrees and about 0.5 degrees.
The remaining figures present results from the time and frequency domain dynamic analyses. The Vessel Pitch and Rotation below the UFJ to Comparing Tension along Riser figure plot respectively the distributions of horizontal motion, rotation, effective tension and von Mises stresss in the riser. (In postprocessing the time domain results, envelopes are generated over the last two wave periods). As with the connected mode analysis there is very good agreement between the time and frequency domain approaches. The large dynamic variation in effective tension (Comparing Rotations along Riser figure) due to the vessel heave is noteworthy. The von Mises stress distribution (Comparing Tension along Riser figure below) also shows a relatively large dynamic variation due to the tension variation.
Vessel Pitch and Rotation below the UFJ
Comparing Horizontal Motion along Riser
Comparing Rotations along Riser
Comparing Tension along Riser
