same simulation different results

[davidwielemaker]

I have been busy optimizing a complex part (see image below) and noticed something very weird a few days ago. The results of my simulations suddenly changed (much higher stress and deformation values for the same model).

As a check i have compared stored results from dec 15 with a rerun of the same simulation (cloned the study and recalculated). So when looking at the results below, the only difference between them is the date when the solution was made (15 dec vs 28 dec).

I'm hoping someone can give an explanation for what is happening here, and which of the results (if any) are to be trusted.

Thanks!
David Wielemaker

[TheCADWhisperer]

Can you File>Export your *.f3d file to your local drive and then Attach it here to a Reply?

[davidwielemaker]

Thats what i forgot to do, here you go.

[James.Youmatz]

Hi @davidwielemaker,

I won't be able to check the .f3d model for a little bit, but from your pictures, it looks like there is a second load applied in the bottom picture as compared to the top one:

Your first picture does not seem to have these loads applied. If this is not the case, I will have to check the model in a little bit and get back to you.

Thanks,

[davidwielemaker]

Hi James,

In the top picture the same loads are present, but the arrows are inside the model so they don't show up in the picture.

David

[Andrew.Sartorelli · Accepted solution]

Hi @davidwielemaker,

I had a chance to speak with some folks from the development team today. They are currently aware of an issue where load cases are having an additive effect with the latest release. We recommend for the time being that each load cause be run in a separate analysis. Simply clone each analysis and delete all but one load case, repeat this for each load case in your initial analysis. Sorry for the inconvenience of this workflow, I know it essentially defeats the purpose of load cases for the moment, but the team is hard at work on implementing the fix.

Best Regards,

Andrew

[davidwielemaker]

Hi andrew,

Your workaround fixed my problem, thanks!

It is a bit more work but still beats the heck out of the alternative for me (setting up the same simulation in Abaqus which is about a day work for each load case!).

[Anonymous]

I've been using the same model to study buckling and have been getting different results. I use a script to remake the same model and have one load case for each structural buckling simulation (one with one load and one with three loads). After doing this a couple of times I've noticed that there are basically two ballparks of results. I'm not sure how to go about solving this issue.