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Home > List of Keywords > *MOORLINE, file $path

*MOORLINE, file=$path\filename.dat

Data format:

One single line with 5 values

GR IDIOD NBZ IDRAW IOP

Status :

Conditionally required

Purpose :

To associate the group IGR with an existing mooring file containing the offset/tension law for an anchor line.

Details :

Parameter Description
$PATH\filename Definition of the mooring file to be
used.
IGR Identification number of a previously defined *RISER if IGR >0. If IGR<0, IGR is a apring element number, it is used for simple load excursion file without the line elements
IDIOD Identification number of the line in the mooring file
NBZ Number of drafts used in the mooring file, can be zero if provided in the mooring file
IDRAW Obsolete
IOP=0 Base option 0
For frequency domain analysis:
IOP=1 : The line modeled with elements is used to compute the static position and the file64 is used to compute the frequency domain response
IOP=2 : Same as previous but after the frequency domain is performed, the line quasi-static displacement is recomputed in frequency domain
IOP=3 : Same as previous but the line complete frequency domain response is recomputed.

For a selected line, the mooring file defines a database of the restoring force for various relative positions of the line ends. The line is assumed to be in a plane (X,Z)

The file structure is presented below :

  Number of mooring lines

  Iline1

  NB_X V1

  H1 abs(Fx_1)    abs(F_Total_1)

  H2 abs(Fx_2)    abs(F_Total_2)

  ... ... ...

  ... ... ...

  NB_X V2

  H1 abs(Fx_1)    abs(F_Total_1)

  H2 abs(Fx_2)    abs(F_Total_2)

  ... ... ...

Note

  1. The file is calculated once for all in a specific static analysis (see predefined results > mooring file). It can then be used as an input for the dynamic simulations.

  2. Several lines may be defined in a single file. They are identified by a specific number Iline1.

  3. All the nodes of a MOORLINE are not consider as a degree of freedom any more; Their positions are up-dated at each static or time step according to the top tension using the catenarys equation.

By doing so, the quasi-static evolution of the mooring lines can be visualized in the animation and the usual post-processing can be used. It must be noted however, that the assumptions (simple catenarys equation) used to update the node positions may induced local spikes in tension (purely numerical ).