Hello all,
I would like to set up a combined topology and free size optimization. Okay, here is what I would like to do in more detail:
My initial design space is a cylinder with a 3 mm thick wall.
First, I want to optimize my part with the objective to minimize compliance and the constraint of a maximum volume fraction of, let's say, 30%. Like this, I get the main directions of stress and I see where material has to be. Since the material is pretty thin in the first place, it only takes material away and if I compare the deformation of the original part with the optimized part, of course, I get higher deformation values for the optimized part because there is less material. Therefore, step two:
Now in this second step, I would like to take this optimized structure, turn it into a shell, increase the shell thickness T to 6 mm and perform a free size optimization with the objective of minimizing the volume and two displacement constraints. One for torsion and one for bending.
I'm imagining an optimized structure, where I have a thicker wall, where the material is really needed to fulfil my deformation constraints and maybe thinner walls, where the stresses are not as high.
I tried to use OSSmooth to turn the resulting part of step 1 into an IGES geometry and then use auto midsurface to turn it into a shell. However, auto midsurface does not recognize the part as a solid and therefore does nothing at all when I want to create the midsurface.
Just performing step 1 with a thicker wall also doesn't work, since the loads on the part are comparably small and I don't get reliable optimization results when I add even more material in the design space. To illustrate how small the loads are, I calculated by hand how much material I could theoretically remove before the material will enter a plastic deformation. I could remove 90%.
Thank you very much for your help!
Best,
Chris
