Strategies for handling Warnings in Abaqus 2

[OptiEng]

Hello all,

I would like to ask some experienced engineers and abaqus users how they handle warnings during an analysis. I tend to get a few of them which ever analysis I run. Being quite new to abaqus I don't always understand the warnings. Any tips/advice on this?

Thanks

OptiEng

 

[rstupplebeen]

I'm afraid that it is probably more an experience thing than a list of things to check. I think all the definitive stuff has already been provided in the error and warning messages. Abaqus does create sets of nodes and elements that may be the culprits.

Calling tech support or posting here are probably your best bets.

The good news is once you develop the experience for your specific problem set is that you now have some serious job security.


Rob Stupplebeen

 

[OptiEng]

Thanks for your response. This has got to be the best, most professional, active forum on the internet for engineering (even for anything!). It has been very helpful. That is made possible by people like yourself helping the engineering community. I hope I can help others too.

For some warning messages, it must be due to my modelling techniques. I hope that with time I will become more accurate, effiecient and better at understanding the outputs.

I will keep working at it, keep checking out the abaqus manuals and if I still need input I will post.

Thanks again

OptiEng

 

[xerf]

Nowadays it is almost impossible to get a perfect warning free analysis.

 

[OptiEng]

(1) ***WARNING: ROTARY INERTIAS ABOUT GLOBAL AXIS-I AND GLOBAL AXIS-II MUST BE SPECIFIED WHEN USED WITH BEAM IN A PLANE

I don't understand this warning. I have a 2-D plane disc and have applied a rotary Interia about the z axis. I have not stated the inertias about x and y. I assume this is why I obtained the warning? Do I need to state an inertia about the x and y?

(2) ***WARNING: FINITE ROTATION BOUNDARY CONDITION SPECIFIED IN MULTISTEP THREE-DIMENSIONAL ANALYSIS. TYPE=VELOCITY SHOULD BE USED

A applied a rotation of 6 radians of disc about the z axis (centre point of disc), is this saying I should have applied a velocity instead?

(3) ***WARNING: DEGREE OF FREEDOM 6 IS NOT ACTIVE ON NODE 1 INSTANCE DISC_1-1 - THIS BOUNDARY CONDITION IS IGNORED

I warning mesage for every node in my model? I can't seem to get rid of it?

(4) WARNING: Boundary conditons are specified on inactive of 2817 nodes. The nodes have been identified in node set WarnNodeBCInactiveDof.

Again I can't seem to aviod this warning message, but unsure why? Also, where can I find "node set WarnNodeBCInactiveDof"?

(5) WARNING: There are 2 unconnected regions in the model

I didn't want any connected regions in my model so I can ignore this one.

(6) WARNING: The system has 1 negative eigenvalue.

According to the abaqus manuals this is instabiliy of the model, which would be caused by buckling.

Any input into these warnings would be much appreciated.

Thanks

OptiEng.

 

[OptiEng]

Really sorry for posting so many questions, but does anyone know how to find nodes (e.g. how I find node 5 in my model? rather than manually finding it?

Thanks

 

[rstupplebeen]

In the results look for the node sets folder. It probably shows up there. Sorry no time to help with the previous list.

It's good to see you helping other people out.

Rob Stupplebeen

 

[OptiEng]

Hi, do not worry about not responding to the warnings, it also me trying to work through the problem myself, by writing it down and thinking it through.

I am really glad I can start to help others too, I guess it shows how positive and useful this engineering community.

I still havent spotted the option for finding specific nodes, but I will keep working on it. Thanks.

OptiEng

 

[rstupplebeen]

Check out the attached picture.

Rob Stupplebeen