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bernd wrote: ping
HarryvL wrote: ping
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Moderator: bernd
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[mention]user-name[/mention]
bernd wrote: ping
HarryvL wrote: ping
thschrader wrote: ping
Yes, meshing is the fun part.
I feel tempted to disagree. Rather hot topic indeed
a friend of mine, did something interesting some time ago... I have to find out his suggestions
definitively yes!
He sent me some details, not the file, 2 years ago... I pinged him to know if he improved his method to have something to be usable...thschrader wrote: ↑Mon Jul 18, 2022 12:52 pm Impressive!
Maybe he can share the file?
Background/colorbar looks like FC...
Unfortunately I'm not confident in FEM, so I cannot reproduce it on a test file (which I don't have)The steps are:
- Make the layout
- Import the copper into FreeCad using ‘fcad_pcb’ https://github.com/realthunder/fcad_pcb
- It is smart to set the copper thickness to multiple of actual thickness as meshing thin layers is a PITA.
For 35um board I used 200um. You can account for this later lowering the copper thermal resistance and specific heat by the same ratio.
- Import only copper which will have some thermal effects (you can specify which nets you want to import)
- Import parts into FreeCad. If needed arrange and align them as needed
- For FEM analysis you have to prepare the model
- Select all the parts then Part Workbench/Split/Boolean Fragments
- In the data tab change Boolean fragments mode from Standard to CompSolid
- Select all then Part Workbench/Compound/Compound Filter
- Create FEM analysis
- Set the analysis to thermomechanical
- Add all the materials (copper, FR4). Add solids to specific materials.
- Add boundary conditions (initial temperature, heat dissipation through all surfaces, heat generation, …)
- Add mesh. This the weakest link. With Gmesh I could make a mesh for simple designs (without via’s) while with complex designs I had better luck with netgen. But Netgen generates big meshes even with Very Coarse settings.
- Write .inp file (this will take some time)
- Run the simulation (this will also take some time)
I had trouble with Calculix - it said some of the solids didn't have a material assigned.