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Multi Structure Floaters

This is a specific type of floaters that requires a beam model and a panel mesh associated to each beam of the model. Some background on this specific feature can be found in Substructures.

In order to introduce such floater in DeepLines, some files must be generated. A substructure is a beam element or a group of beam element of the floater.

  • A tdl file used to describe all the lines and connections representing the floater,
  • One panel mesh file par substructure,
  • One hydrodynamic database with hydrodynamic data per substructure.

Therefore, a mesher and a potential flow software are required. The procedure below is based on ISYMOST (mesher) and DIODORE (potential flow). The initial beam and panel mesh is created in ISYMOST and can be automatically exported to DeepLines (via .tdl and mesh files) and Diodore (input file .inp and mesh .msh). The general preocedure is is the following:

For connections, it is assumed to be rigid connection but a specific mesh is defined for the connection. Therefore for both beam and connections, the hydrostatic and dynamic is obtained from potential theory with the panel mesh of the floater and not by equivlent beam properties. See the example of mesh around a connection:

In the .inp file used as an input for Diodore, the reduction point must be defined.The .inp file contains also all the substructure definition.

The substructure (for instance CCn_1 above) will be present in the .tdl file generated by ISYMOSTand in the hydrodynamic databse generated by DIODORE. An example of the specific keywords required for substructures is (see also HDB files:

The .tdl file (see also Imported lines) contains the beam mesh and properties. Additional point loads (*ANCILLARY) can be added.

Each floater is then characterized by a number of data:

  • General data : these include the name of your floater, the reference in global frame and the initial heading with respect to the X-axis direction.

  • Drawing : display the floater in the 3D view window.

  • Motion : options for motion calculations.

  • Fairleads/Hang-off points : this defines fairleads and hang-off points linked to the floater which can be used to connect other model components. You may create as many fairleads and hang-off points as desired.