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Shape optimization leading to singular matrix in BEM
Posted 10 dic 2024, 14:35 CET Acoustics & Vibrations, Optimization Version 6.3 2 Replies
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Hi,
I'm trying out shape optimization for acoustics and it seems to work nicely in FEM. Building the same models with BEM however, I get the "singular matrix" error after adding the shape optimization stuff in.
To counteract the possible underconstriction, I tried adding in stuff like another free shape domain on the outside of the free shape boundary, roller/symmetry for the boundary on the symmetry plane and fixed edge around the free shape domain but those didn't help. Also checked the material assignment ten times. I went through pretty much all the settings though I hardly understand a fraction of them, lol
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Hi Tuukka
There is a warning under the Compile Equations feature saying that the domain is not meshed. This is the immediate reason for the singular matrix, i.e. there is no volume mesh for the Free Shape Domain. You can avoid the need for a volume mesh by using a Free Shape Shell feature, but adjoint sensitivity is not supported for BEM in COMSOL 6.3 (latest version in time of writing), so you will have to try and solve your problem using FEM.
Best regards,
Kristian E. Jensen
Technical Product Manager, Optimization
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Thanks, things make sense now! Are there any plans for the implementation (or workarounds)? Seems like quite a bit of "wasted" potential