John Doyle
Ansys Employee

What you are describing is the very last step in the process of implimenting a customized user routine that is not available as a standard option.  If you are sure that you need a user routine to represent your material behavior, then you need to write the user programmable routine and link it into the standard code, before you can use it.

I would refer you to the MAPDL Programmer's Reference Manual available online for all these details.

Programmer's Reference (