Has anyone used the UMATHT subroutine in CalculiX before?


I want to add the internal energy generated as a result of reaction kinetics to the system by using the u (internal energy) variable in the umatht subroutine, but it says “not used” for the u variable. I think I need to make some edits in CalculiX codes to use this variable as in Abaqus, how can I do that?

I will be grateful if you could help me.

Screenshot from 2022-05-12 15-25-00

@Makkus Dear Makkus.

the heat transfer subroutine is significant for many System not only thermal problem.

This is to say, we must modify whole Finite Element processes,
such as element, solver(*coupled displacement-temperature), Stiffness matrix, and so on.

for my view, if the Calculix can support this UMATHT part like the UMAT,
the Calculix will bring a new change.


if you wanna modify whole source of Calculix, you can support the UMATHT.
if you cannot modify whole source of Calculix, just wait the Calculix team.

so do I.