Optistruct random response analysis

timonq

Hi,

Is there somebody who use Optistruct to calculate PSD/Random analysis? I know that it's possible, I know how to do that and also I prepare this in my job (I used to work in Nastran, .fem and .bdf files are almost the same).

But I have another question: use somebody this solver in job for this type of analysis? How about results comparison between Optistruct vs. Nastran and Abaqus? I asked, because I heard that it is not good idea to use this solver for dynamic calculations. Have you any examples, comparisons, articles etc. focused on obtained results from this type of analysis?

I prepared similar analysis in Optistruct and Abaqus (our main software for FEA), and RMS stresses are 10% lower in Optistruct (tomorrow I check both models again). I observe that Optistruct solver is much faster when I set output for all frequencies (opti 20min, abaqus 3h /emoticons/default_blink.png' title=':blink:' /> ), when I set output only for last frequency opti:15min, abaqus 25min.

So that's why I'm asking about this /emoticons/default_biggrin.png' srcset='/emoticons/biggrin@2x.png 2x' title=':D' width='20' />  

 

Thanks in advance /emoticons/default_smile.png' srcset='/emoticons/smile@2x.png 2x' style='border-style:none;vertical-align:middle;' title=':)' width='20' />

Rahul Rajan_21763

Please refer below Random Analysis  & Optimization  online tutorials.

OS-1325: Random Response Analysis of a Flat Plate

OS-3030: Random Response Optimization

You can contact local Altair Support for comparison & other relevant information.

kalaiselvan_22516

I have ASD value as 0.003 g2/Hz.  Should i enter directly the given value in TABRND1 or should i convert. Pls explain. Unit load i hv given as 9810 in X direction (SPCD = ACC)

.  I have clinet datas 0.76 Grms value (30 minutes).

 

Adriano_Koga

your units should be consistent though all your model, that's the main point.