mooring failure

[sby147]

Dear experts, hello. I am a floating wind turbine floating body engineer. May I ask how to use the mooring failure function on the existing 3.5.3fast version? Can I directly modify the moordyn.dat file and use openfast.exe to run it, or do I need to modify the source code? I also referred to the topic of "Tendon failure in FAST modeling" in the NREL Forum, but did not get any inspiration. Can you provide some guidance if you want to modify the source code?

Best wishes
sby147

[jjonkman]

Dear @sby147,

The ability for the user to support mooring line or tendon failure through the MoorDyn input file was added in the release of OpenFAST v4.0; see the following pull request for details: OpenFAST/openfast#2214. So, the easiest way to invoke that event would be to upgrade from OpenFAST 3.5 to OpenFAST v4.0.

Best regards,

[sby147]

Dear jjonkman,

Thank you very much for your suggestion. I have updated my OpenFast to the latest 4.0.5 version and completed the setting of mooring cable break conditions, achieving ideal results. How should I set up the simulation of dynamic power cable movement now? How can devices such as bends, J-shaped pipes, and buoyancy blocks for power cables be coupled and used in the mood without requiring the addition of servo control functions?

Best regards,

[RyanDavies19]

Hi @sby147,

Dynamic cables in MoorDyn are simulated as line objects with non-zero bending stiffness. This paper lays out the approach: https://asmedigitalcollection.asme.org/OMAE/proceedings/IOWTC2021/84768/V001T01A011/1107730

Typically for buoyancy we distribute the properties along the cable in the buoyant section rather than simulate the individual buoyancy modules. However, for improved hydrodynamic effects it is possible to add rod objects in-line with the cable that act as these buoyancy modules.