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von Mises RMS Stress

Hi

 

Is there a way to suppress the calculation of the von Mises RMS stress (which I assume is the time consuming calculation) in the case control STRESS request?

My model takes too look and uses too much disk space in calculating random stresses so I would like to calculate a pseudo (max possible) von Mises RMS stress using the other RMS stress components (X, Y and XY) in FEMAP.

Even if I ask for STRESS(SHEAR)=ALL or STRESS (MAXS)=ALL, the von Mises RMS stress is calculated by default for a random analysis.

 

Thanks

4 REPLIES

Re: von Mises RMS Stress

System cell 579/FREQVM. See the Basic Dynamic Analysis User's Guide documentation at:

 

Frequency Response Solution Control and Output

Re: von Mises RMS Stress

Hi JimB

 

With the setting

NASTRAN FREQVM=1

and request

STRESS(SORT1,PRINT,CENTER) = 1

I still get von Mises RMS stresses in my f06 file.

I also get corner stresses , when I am asking for CENTER output.

 

Am I missing something?

 

 

 

Re: von Mises RMS Stress

Hi JimB

 

I did further checking

 

Nastran FREQVM=1 does turn off the calculation of von Mises stresses in a frequency response run, but not a random analysis.

 

Stress(CENTER)=ALL outputs stresses at the corner of the elements too. Should this be the case? The manual says "Outputs stresses at the center of the element only."

 

Any other ideas how to suppress the von mises stress calculation in an random analysis?

I am using Nastran 11.0.1

 

Thanks

Peter

Re: von Mises RMS Stress

[ Edited ]

VM stresses aren't what takes a long time in SOL111, stresses in general do. Even if you use the XYPEAK method instead, it will still take forever... But at least XYPEAK will give you what you want. Setting up the XYOUT requests is easily done with FEMAP...