Warning messages for boundary conditions

[Sara.......]

Hi!
I am doing a time history analysis in Abaqus in a dynamic implicit step, but I have the following warning:

OVERCONSTRAINT CHECKS: THERE ARE 12618 BOUNDARY CONDITIONS SPECIFIED IN THIS MODEL. OVERCONSTRAINT CHECKS FOR BOUNDARY CONDITIONS SPECIFIED ON SECONDARY NODES OF RIGID BODIES, OF *TIE OPTIONS, OR OF *COUPLING OPTIONS REQUIRE 5 MB OF MEMORY. IF THIS IS A PROBLEM, PLEASE TURN OFF OVERCONSTRAINT CHECKS USING *CONSTRAINT CONTROLS, NO CHECKS or INCREASE THE MEMORY USED BY THE PRE-PROCESSOR.

I use C3D8R elements and Tie constraints (but not at base node). At the base, I apply fixed boundary conditions for U2, UR1, UR2 and UR3, while in directions 1 and 3, I apply different accelerograms.

Do you know why there are these warnings?


Thanks.

 

[FEA way]

It doesn’t sound like something that you should worry about unless there are other warnings indicating problems (e.g. with overconstraints) and you’ve noticed some undesirable behavior of the analysis or suspicious results.

 

[Sara.......]

I have some overconstraints because the geometry is complex and sometimes there are three or more walls tied together.
I also notice that in the .dat file I have these warnings:

DEGREE OF FREEDOM 6 IS NOT ACTIVE ON NODE 6485 INSTANCE Muro 27 - THIS BOUNDARY CONDITION IS IGNORED

For each node also the dof 4 and 5 are not active. This is due to the type of element I use?

 

[FEA way]

If you are using solid elements and you applied BCs on DOFs 4-6 then it's normal because the nodes of those elements don't have rotational DOFs.

Check the results carefully and if you don't notice anything suspicious then there shouldn't be anything to worry about.

 

[Sara.......]

Thanks a lot!