Anyone facing issues when using a combination of UEPACTIVATIONVOL and UMATHT subroutine? When checking standard parameter definition (density, conductivity, spec. heat) via the input file vs UMATHT subroutine, the simulation results are similar. But when adding the UEPACTIVATIONVOL subroutine in the simulation, it looks that the sequence of nodal temperature calculation changes and therefore creates negative temperatures and weird convergence. Time/mesh reduction does not change the behaviour.

Abaqus ​​​​​​​