Continuing our series of posts on upcoming developments for version 10.2, we consider a couple of enhancements to the support and constraint objects.
OrcaFlex objects can be connected to each other, so that the connected objects move together. In addition, certain types of connections can be released at defined points in the simulation. For example, line, link and winch connections can all be configured to release at the beginning of a specified stage in the simulation. Version 10.2 introduces the same capability for supports and constraints.
The new functionality is quite straightforward to use. For supports there is a new data item named release at start of stage. Once released, the supports are no longer active in the model and apply no forces or moments to supported lines. As is the case for other objects, if the release stage is set to ‘~’ then the supports will not be released.
For constraint objects the functionality is similar. There is a new data item named release at start of stage. Once released, the out-frame is disconnected from the in-frame, and the out-frame moves as though all six DOFs are free. Again, if the release stage is set to ‘~’, then the out-frame is not disconnected. Any slave objects of the constraint will remain connected to the out-frame after it has been released.
Some objects in OrcaFlex can be slave objects, but their connections cannot be released during the simulation, for instance buoy objects. Constraints can be used as a means to effect release of such objects. For instance, you can connect a constraint as a slave of a vessel, and fix the constraint’s DOFs. In turn, connect a buoy as a slave of the constraint. The buoy is, in effect, rigidly connected to the vessel, via the constraint. If you release the constraint during the simulation, this has the effect of releasing the buoy, and it will move independently from the vessel.