warning message for boundary conditions.

[Mohamedsayed]

Hello there,

I got two warning messages, could anybody explain them to me, and whether or not they will affect the results.

first warning message:-

DEGREE OF FREEDOM 1 IS NOT ACTIVE ON NODE 3 INSTANCE solid-1, THIS BOUNDARY CONDITION IS IGNORED

My model is 3d, the element is C3D8R, i have constraint (tie) in the model to tie to regions.

Second warning message:-

OVERCONSTRAINT CHECKS: THERE ARE 23520 BOUNDARY CONDITIONS
SPECIFIED IN THIS MODEL. OVERCONSTRAINT CHECKS FOR BOUNDARY
CONDITIONS SPECIFIED ON SLAVE NODES OF RIGID BODIES, OF *TIE
OPTIONS, OR OF *COUPLING OPTIONS REQUIRE 9 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.

Thanks.

 

[burningDiesel]

The problem is you have 23520 boundary conditions.
Other than that, the warnings are not a problem and don't influence your result (the boundary conditions themselves ofcourse do).
The first warning speaks for itself, I can't really explain it better than you have put a BC on an inactive DOF. The reason it is inactive is because you did something to it (MPC or other constraint is most likely).

 

[Mohamedsayed]

My model is a 3D model, it like a box. i fixed the translational and the rotational degrees of freedom of the bottom of that box. I apply load on the top surface, so there is no constraint on the top surface, the other four vertical surfaces are constrained in the X and Y direction.

Other than that, i tied two parts of the model using tie constraint.

I need to understand what is the inactive Degree of freedom? what does it mean? i am sorry to ask that question again.
Also, the number 23520 represents the number of elements which has been constrained?

 

[IceBreakerSours]

As sdebock has pointed out, you may have assigned two different but inconsistent types of constraints on some nodes. If an .odb is generated, open it and visualize the overconstrained nodes; they should be available as warning nodes in the Create Display Group menu. On the other hand, you could open up the .dat file and look up the warning messages and make a list of these warning nodes and see them in CAE.

You will notice, as an example, some of the tied nodes may also be constrained due to the boundary condition(s).

By the way, if you are only using continuum elements (such as bricks), then nodes on these elements do *not* have rotational degrees of freedom.

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