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Mooring Lines
Hello, David，when performing the calculation, the clump weights are located along the touchdown portion of the mooring lines. However, in the software, it appears that the *ADDMASS* setting assigns the entire mass to the platform rather than to the mooring lines. How can this issue be resolved?
Hi Camelia,
the ADDMASS keyword cann add mass and inertia properties to a substructure joint:
For example: ADDMASS_5 10 1 2 3 4 5 6 adds a mass of 10kg at the joint with ID 5. The following numbers assign the rotational inertia in local joint coordinates: Ixx = 1, Iyy = 2, Izz = 3, Ixy = 4, Ixz = 5, Iyz = 6.
BR,
David
Hello David,
Thank you for your reply. We are aware of how to use the ADDMASS setting. However, I have noticed an issue: the added mass specified using ADDMASS is being counted as part of the Substructure mass, rather than as part of the Mooring mass. Could you please advise on how to resolve this issue?
Best regards,
Camelia
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Hi,
I understand your point now.
Indeed, the information dialog attributes all contributions from ADDMASS to the substructure mass. However, please note that the values shown in this dialog are only intended to provide an overview of the mass contributions – they are not used directly in the structural dynamics simulation. In the actual simulation, the additional mass assigned to the nodes is correctly applied, even if it is listed as part of the substructure in the overview.
To obtain a more accurate lumped mass distribution than shown in this overview, you can manually subtract these ADDMASS contributions from the substructure mass and reassign them to the mooring mass. Unfortunately, it is difficult to automatically determine whether a substructure joint should be classified as part of the mooring system or the substructure. As a result, all joint mass contributions are grouped under the total substructure mass in the overview.
Best regards,
David
