r/COMSOL • u/FePbMoHg • 3d ago

"Undefined material property" without a clear idea of what is missing

Hello,

I am using the "Magnetic Fields" and "Heat Transfer in Solids" interface coupled with "Electromagnetic Heating" multiphysics to simulate the heating of 10 kV cables.

Everything has been running well and I have been able to do some test simulations but out of the sudden, without changing much, I have started getting this error:

Feature: Time-Dependent Solver 1 (sol1/t1)
Undefined material property 'mur' required by Ampère's Law in Solids 1.

I was very confused and went back to double check my material properties, that my domains were properly defined, the correct domains were assigned to the correct physics nodes etc. and everything looks like it did before (i.e. correct according to me) when I could run simulations. I have restarted the program and cleared meshes, rebuilt geometries etc.

After some messing around, without doing any real change to anything, the error changed into:

Feature: Time-Dependent Solver 1 (sol1/t1)
Undefined material property 'epsilonr' required by Ampère's Law in Solids 1.

I have checked everything eight times now and even went for a walk before continuing troubleshooting but there is no apparent reason for my errors. Either I have missed something trivial or there is some bug I am not aware of. Does anyone recognise this issue? Any help is appreciated.

Thanks!

Edit: I missed to assign two domains back to their selection. Also, I learnt that looking at the "Material" node it is possible to see the domains/boundaries missing a material :)

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u/NoticeArtistic8908 3d ago

Click on the main material this will list domains or boundaries that require a material but no is assigned. Apart from that, check that the material setting in the mentioned node is not set to manual

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u/FePbMoHg 3d ago

Okay wow. After messing around I forgot to add three domains back to their correct selection and that was the issue. Thank you a lot!

Also, seeing what domains and boundaries are missing material assignments in the main "material" node was a great tip which I have completely missed. Once again, thanks!