Hi Sam,
We’re wrapping up a project where we’ve added the ability to model substructure flexibility and member-level loads to OpenFAST for floating offshore wind turbines. Included in these changes is the ability to enable the SubDyn module to model the structural flexibility of either the floating substructure (with the SubDyn-ElastoDyn coupling at the tower base), or the floating substructure and tower (with the SubDyn-ElastoDyn coupling at the tower top). And with these changes, SubDyn has also been upgraded to include pretensioned cable elements (in addition to beam elements previously available). These pretensioned cable elements can be used to model guyed towers, as long as both ends of the guy wire (pretensioned cable) attach to distinct parts of the SubDyn model. Please see the papers linked in the following forum topic for more information: Extending the dimensions of matrices related to equation of motion - #3 by Jason.Jonkman. We are still verifying and validating this new functionality, upon which these features will be released.
Best regards,