Home > Introduction > Tutorial > Analyses

Analyses

The analyses defined in this example include both quasi-static and dynamic analyses.

Quasi-static analysis

The quasi-static analysis named Static_Offset includes the Riser, FPSO, current and offset components.

The calculation parameters are used to set the type of analysis to be run and allocate contact properties where needed. The quasi-static analysis will be done in 5 steps over which the offset will be progressively applied.

Contact properties are set up from the Contact tab. There is a single contact to be handled in this analysis between the line and the seabed and therefore one row only for the contact parameters setting grid. The density of contact elements was chosen so that one contact element can be activated for each beam element laid on the seabed.

The predefined results tab includes several predefined results requests. These requests will be automatically loaded from the results files when opening the .DSS simulation results file with the GUI.

Dynamic analysis

In addition to all model components present in the previous quasi-static analysis, the dynamic analysis named Dynamic_Regular includes a regular wave component. The simulation period for the dynamic analysis is set to 5 times the regular wave period. Wave loads will be ramped from the start of the dynamic simulation until they reach full amplitude at the ramp time set by the user. This ramp time is generally taken equal to one wave period.

The last dynamic analysis named Dynamic_Irregular includes the same Model Components than the quasi-static analysis and an irregular wave. The irregular wave is modelled through a JONSWAP wave spectrum with 200 individual wave components. The minimum and maximum wave periods used in the irregular wave object must lie in the range of periods present in the set of motions RAO of the FPSO. The simulation is run over 300s and the maximum wave height requested is 1.86 times Hs.