Dynamic                          


Home Up Introduction Design process Contact

 

 

The dynamic analysis is the most sophisticated way of analyzing a mooring system as most mechanisms and effects are now modeled.

There is no universal agreement on mooring line  damping à uncertainties in outcome.

The dynamic design is computationally intensive

The following equations derived by Goodman and Breslin (1976) model the mooring line dynamics:

 

Equations 1 to 5 provide the relationship between five unknowns  which can be solved for the relevant boundary conditions. There is no analytical solution and the problem can be simplified by solving for the static configuration and using this as a starting point for the dynamic analysis.

 

Generally the motions of the semi-submersible are calculated independently of the estimates for the line dynamics. (For deep water mutual interactions need to be taken into account!)

Mooring lines now modeled more accurately: not only mass of the lines (catenary equation) but also damping and inertial effects are taken into account.

Methodology:

Non-linear time domain solutions developed about initial, static position are used.

Mooring lines are modeled by decomposing them into lumped mass elements at the ends of line segments

Remarks:

bullet

Time steps must be small to include wave induced line oscillations

bullet

Runs must be long enough to incorporate the semi-submersibles drift oscillation period

bullet

Weather is multidirectional; several runs to model that.


 

       

                                                                     

 

 

 

Send mail to m.h.p.bijl@student.tudelft.nl with questions or comments about this web site.
Last modified: 10/16/06