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Not getting buckling shapes and mode factors

Hi,

 

We are using NX10 for static and buckling analysis. During the simulation of buckling analysis we are not getting the buckling mode shapes and buckling factors.

 

This problem is arising for some particular models only. We dont know the reason why it is showing like this. In the analysis results it is showing the stress results only.

 

Kindly help us in solving the solution.

7 REPLIES

Re: Not getting buckling shapes and mode factors

I guess you are only getting the static solution because in the range of frequencies requested there are no buckling modes. If you get negative values means that the load direction must be opossite to have buckling failure. I think f06 gives an "error" saying that no buckling modes are found in range of interest

Re: Not getting buckling shapes and mode factors

Thanks for your response. For this what can i do now?

 

Whether i have to increase the mode numbers or some other?

 

Re: Not getting buckling shapes and mode factors

I do not know anything about your model but you mentioned that your are getting the static solution, aren 't you?. And also in some models you are getting the buckling solution. That means that if the frecuency range of interest let's say is  from 0 to 5

- some models the buckling occurs in this interval

- in the other no

. In the analysis settings you must be able to modify this. Are you not getting some warning saying that no buckling modes were found in the specfified range. Simply that means that you need higher loads to produce buckling

 

Re: Not getting buckling shapes and mode factors

In my model i didnt set any frequency range. When i open the op2 file it is showing this error.

 

Finally, In the analysis settings if i change the no of desired modes to 50, will i get the buckling mode shapes and factors.

 

1.JPG

Re: Not getting buckling shapes and mode factors

Myabe It could help. But the buckling analysis is like modal analysis. You usually specficied the range and the number of modes. If you specfied just the number it should calculate but it could take long time until the 50 are found. 

 

what it is strange is that the f06 can not be opened becasue it is too large. Many singularities?

Re: Not getting buckling shapes and mode factors

 Karthikeyan_E,
 
I had a lot of problems with large F06 files, too.
Sometimes it depends on a really huge amount of grid point singularities if having solid elements. Every rotation degree of freedom is sigular and NX wants to tell you that and afterward it is suprresing the rotational DOFs.
 
In that special case you can switch off the "Grid Point singularity table" in Parameters with
PRGPST = NO

 

 

2017-05-29_091137.png

 

 

Additionally I use "Notepad++" for large Ascii files like F06.
 
Best wishes, Michael

 

 

 
 

Re: Not getting buckling shapes and mode factors

You are right Midi1791.