I am trying to run a simulation for the rolling of a solid disc. For the material definition, I want to use a UMAT subroutine. However, as soon as the Steady State Transport step begins, the run aborts with the following error in the message file.

***ERROR: USER SUBROUTINE UMAT_SST IS MISSING

How can I overcome this error? Any suggestions?

I have attached the .inp files and the sample UMAT file in a zip archive.

Thank You
Feby