Inertia Releif is activated via PARAM, INREL. Setting this to -2 requests automatic inertia relief (no SUPORT entries needed). A setting of -1 is manual (user specifies SUPORT dof).
See the User's Guide and the Quick Reference Guide for more details.
If using param inrel -1, how do I specify SUPORT entries within the NX interface though (specifically, NX10)?
I can turn on the checkbox for "inertia relief", edit the parameters to include inrel -1, but the software doesn't do a very clear job in telling the user how to add these entries in. I tried to do it manually by specifying key-in text under solution-->bulk data-->DOF sets --> user defined text, or dropping it into the .dat file at runtime, but neither of these options neemes to work.
On the Solution dialog, toggling on the Inertia Relief (INREL) checkbox will cause PARAM, INREL, -2 to be written to the input deck. This requests automatic inertia relief.
To define manual inertia relief, leave this toggle off. On the Solution Bulk Data tab: