I noticed the Controlled pre-tension cable capability available in SubDyn, and I have the following question.
As far as I understood, it is possible to describe a change in cable length in function of time (only in the direction of cable shortening). First question: is there an example file on how this is implemented?
Second point: in theory, it should be possible to prescribe a reduction in length of the cable such that the pretension goes to zero, which would be the same as losing that pretension cable. Could this be implemented?
I suppose the eigenmodes/eigenfrequencies derived by SubDyn at the beginning depend on the pre-tension in the cables. SO, if I change the tension in the cable, should not these change?
These questions arise from the fact that I would like to simulate the IEC 61400-3-2 DLCs where there is a loss of a line (9.1, 10.1), but at the moment the only way I see is to:
A. Run the simulation with all the cables intact, up to the time t = T_loss
B. Copy the state at time t = T_loss of all the DOFs which can be specified in ElastoDyn.dat as INITIAL CONDITIONS
C. Run a separate simulation, removing the cable lost, and running the simulation (although I would not know how to say to OpenFAST how to resume from the wind speeds and wave elevatoin time histories at
time t = T_loss).
Maybe there is a better way?