A model from Workbench Simulation 11.0 is brought into ANSYS Classic and it fails with a constraint equation error unless NSUBST,1,1,1 is used:

*** FATAL *** CP = 9.438 TIME= 18:35:24
A term of constraint equation 13 is not defined, most likely due to a
displacement constraint on this or an adjoining constraint equation.

The model has MPC contact, but the nodes are not restrained via the D command, and there are no constraint equations in the model (other than the internal ones from the MPC contact). It seems running a
nonlinear analysis causes the MPC contact to fail, but it works for a linear analysis. Is this a known error?

Yes, Defect 65275 was filed and corrected in the 12.0BETA UP20080229 build of ANSYS. Development noted the following about the error:

The error was due to the way we were storing the constraint equation numbers based on nbce (an internal variable). This variable was being reset in a manner that contradicted the code in the mpc184 routines under certain circumstances as this problem. An alternative storage scheme has been set up to correct this error.

Show Form
No comments yet. Be the first to add a comment!