Random Vibration RMS stress evaluation per prefequency using Optistruct

Lesther Mae
Lesther Mae New Altair Community Member
edited October 2020 in Community Q&A

 Good day!

 

I am doing Random Vibration Simulation project using OptiStruct and our Customer require us to evaluate RMS stress at every single mode to verify the effect of the mode on the system/module.

Now, what we already know here is the RMS stress throughout the simulation and not per frequency.

Is this possible in OptiStruct?

Please help us how and what inputs we should integrate in our model so that we can be able to evaluate the RMS stress at every single mode.

I really appreciate your response since this is very urgent.

 

 

BR,

Lesther

Tagged:

Answers

  • Robert Lawson
    Robert Lawson Altair Community Member
    edited November 2019

    I'm not sure I follow this, but I'll try.  Also, I'm not sure this is a reasonable request from the customer.  Though 'the customer is always right' as they say.  ;)/emoticons/default_wink.png' srcset='/emoticons/wink@2x.png 2x' title=';)' width='20' />   So they are asking for each individual mode's contribution to the overall RMS stress?   

     

    Typically, I would plot the Stress PSD for high stress elements of interest.  From that you'd expect to see peaks at pertinent modes.  Then you could go view those mode animations and confirm that the Stress PSD output makes sense and is believable.  If that's not sufficient for this customer... hmmm.

     

    How many modes do you have in the frequency range of interest?  If something small-ish like 10-20ish, you could use MODESELECT case control to select one mode at a time, and re-run the simulation.  This is a bit clunky.  If you've got >20 modes, this is busy work.  If you have to do this for a lot of elements/responses --> really no fun at all.

     

     

Categories