RAM Advanse: Error message for a non-existent member

[imsengr]

I have been getting a very unusual error in the analysis of the latest revision of my structure, a tall, wide but slim structure. This is how it read:

"Error: Instability Found @ Node Rigid end J for member 521 (2.55, 6.04, 1.22) @ DOF UZ. Check the Element End Releases or Any Boundary Conditions Defined at the Node. Analysis cancelled."

When I tried to locate member 521, I find that there is *NO* such member! and got a warning that, "Member 521 does not exist. Unable to select it."

Has any one of us come across this error message before? I would think that it is unusual for RAM to find a problem with a member that does not exist. Why is RAM Advanse advising me of instability with a member that apparently does not exist?

Thanks in advance for all your advice and suggestions.

 

[UcfSE]

Try calling tech support. Thoroughly check your model.

 

[imsengr]

Thanks, UcfSE. I have checked with Tech support and was told I that even though the member where the error was showing did not exist on my physical model, it apparently does exist in tht FEM model that RAM generates for the analysis. RAM apparently internally segments all my members and meshes my shells in finite elements for the analysis. I can actually see which member RAM is referring to by selecting the Finite Element model in View from the top menu.

Now, I've got another problem, different from the one above. In running the p-delta analysis for my model, I am getting numerous, "Iterative analysis for (load combination) failed." errors referring to my various load combinations. (Note: This error doesn't appear when I am running it for first order analysis, and not the p-delta analysis, though. Why the difference, and can I just accept the first order analysis as sufficient?)

Now what is RAM trying to tell me? Can anyone of you suggest what is the best way to debug my model to see where it is failing? Thanks in advance.

 

[goncho]

Hi,
P-delta is an iterative non-linear analysis then in some load cases probably do not converge, you can change the parameters in the analysis form,like increse iteration number or iteration steps or decrese the tolerance the parameters by default are:
Number of steps= 1
Number of Iteration= 10
Tolerance = 1.0e-5

then you can chane those parameteros to:

Number of steps= 2
Number of Iteration= 100
Tolerance = 1.0e-3

try this, please