SEMI-SUBMERSIBLE TOPOLOGY OPTIMISATION
In the quiet week between Christmas and New Year we spent a few afternoons investigating some structural optimisation tools and we thought we'd share some interesting results with you. We decided to look at a floating wind foundation concept for this, as there are approximately 35+ design concepts out there already. We also decided to keep things symmetrical, so the turbine is located at the centre of the foundation. We used the feature built into ANSYS to perform topology optimisation of a floating foundation, to optimise for minimal mass within some fixed constraints.
Taking a tri-floater design with three main buoyant volumes placed at 120deg.
The turbine is the DTU 10MW reference turbine to represent the next generation of turbines to be used in floating offshore wind
The load case was a simple arrangement to understand where material was needed to react the turbine thrust force (at rated power) and keep the unit afloat
The optimisation was set up with different minimum member dimensions (ticking over in the top left corner of the animation). At very small member dimensions the tool had a tendency to favour complex internal structures, something that could be 3D printed, but was not a realistically feasible solution at this scale in the real world. As member size increases you see the material tending toward more common engineering design practices for managing stress pathways with ribs appearing and finally more of a truss structure.
We have a number of in house optimisation codes, so it was interesting to see how this tool within ANSYS worked and produced results that could be interpreted by our engineers. It got us thinking about optimisation targets and integration of separate tools and ideologies in renewables design that aren't all tied into the final objective.
Do we have a solution? Maybe, just maybe... watch this space!