I am testing whether native "ELAS_HYPER" in Code_Aster can be used for thermal shrinkage of rubber. This is to simulate the rubber part shrinkage after molding. I used Code-Aster 18.0.12 modified on 2026-04-03 version.
My initial idea was to:
- define "ELAS_HYPER" for the hyperelastic law,
- add "ELAS=_F(ALPHA=...)" to provide thermal expansion,
- pass temperature evolution through "AFFE_VARC(NOM_VARC='TEMP', EVOL=...)".
But Code_Aster stops in "DEFI_MATERIAU" with:
“At most one argument of ('ELAS', ..., 'ELAS_HYPER', ...) can be defined.”
So it appears I cannot combine "ELAS" and "ELAS_HYPER" in the same material just to add "ALPHA".
Does this mean native "ELAS_HYPER" has no supported path for thermal strain coupling in this workflow? If so, is MFront the recommended route for thermo-hyperelastic rubber shrinkage? Any test cases? I checked the forum for previous posts, couldn't find one.
If I use only ELAS, the simulation direction is correct, but the values are off depending on the geometry of the product, compared to validated results. ANSYS does this very precisely.
