Normal Modes Animations Middle Frame is Max Stress

[Anonymous]

Is it possible to show the middle frame of a Normal Modes Animation to show the min Stress instead of the max stress color in the middle of the animation? This makes for some irritating images to display.

To Recreate:

Take a solid and and constrain it.

perform an normal modes analysis

animate with von mises stress

set animation option to oscillation

[John_Holtz · Accepted solution]

Hi @Anonymous 

I think that I understand what you are asking, but it took me a long time to find the options. Let me repeat what I think you are seeing so that other readers can follow along.

In the Inventor Nastran environment,

1. "System > Default Settings > Post-Processing > Mode > Oscillate". (I did not know that this option existed!) Change the number of frames if desired.
2. Run the modal analysis.
3. Display the von Mises stress result (or any result).
4. Click the "Animate" button. (Or right-click on Results in the model tree > Animate).
5. The selected mode shape is shown "vibrating" in a sinusoidal fashion. It
   1. starts at 0,
   2. animates to the maximum value,
   3. then back to 0,
   4. then in the negative direction,
   5. and finally back to 0.

The problem I see is that at the end of step 5.3, when the model should be 0 result, the color shown on the model is red (implying the maximum result!) instead of blue (which is normally 0 but not necessarily 0!). 

Is this what you are asking about? If so, that appears to be a software issue that a co-worker recently discovered. The "0" state is shown as red instead of blue.

[Anonymous]

Yes that is exactly what I was talking about.

Please keep me posted if there is a patch it would make sharing my output much nicer!! As it is now I mostly opt for sharing deformed shapes only. 

Sorry for not being more descriptive in my description. The oscillate option is very nice when showing it to other people as they do not have to imagine how the system will move through the other half of motion. Truthfully it would be nice if it was the default setting for vibration analyses as 9 times out of 10 people would rather see the full oscillation. Although there is the nice part of the setting full which shows a half sin animation having a faster loading time. although if i was optimizing for loading time i would want half (quarter sin animation) as default. But as I said most of the time I am just setting it to oscillation.