Dividing a single step into two parts with loadcurves

[LouiseD]

Hi everyone,

I'm working on folding a balloon. This balloon is attached to the stent via a contact tied for a few faces of the stent. Using normal displacements for a selection of facets I succeeded in creating 6 folds. Then, I used another Normal Displacements command to push the balloon further towards the center line. It's a step I implemented because the folding alone was reaching a limit and the stent was not folded enough (its folded diameter was still too large). The second step allows reducing a little bit more its diameter.

So I succeeded creating a simulation in two steps. I was wondering if there was a way to put everything in one single step, and using the load curves to handle the appearance of every command. My load curves look like this:

For the first half of the step:

<load_controller id="1" name="LC1" type="loadcurve">
<interpolate>LINEAR</interpolate>
<extend>CONSTANT</extend>
<points>
<pt>0,0</pt>
<pt>0.5,1</pt>
</points>
</load_controller>

And for the second half :

<load_controller id="2" name="LC2" type="loadcurve">
<interpolate>LINEAR</interpolate>
<extend>CONSTANT</extend>
<points>
<pt>0,0</pt>
<pt>0.5,0</pt>
<pt>1,1</pt>
</points>
</load_controller>

When I launch the analysis, it crashes almost immediately. I was therefore wondering if such use of load curves is possible.
I attached my file.

Thanks for your suggestions!
Louise

[maas]

Hi Louise,

The model is not converging because nothing is happening in the model. (FEBio often fails to converge when the loads are not changing since it's trying to reduce what effectively is numerical noise.) The reason nothing is happening is because your (zero) prescribed displacements are applied to facets that overlap with the selection assigned to the normal displacements. You have to make sure that the two selections do not overlap.

Best,

Steve