Plotting contact variables when multiple contact conditions are defined

[agalloy]

Hello,

I am working on a model that has 3 surfaces with contact pairs defined between each of them. I want to plot the contact gap and contact area for each of the contact conditions separately.

In my current .feb file I have my plot file set to include the contact gap and contact area variables, but when I open the file in Postview I get a pop-up that says "WARNING: Duplicate surface values encountered". This makes sense since each surface will have two contact conditions, but is there a way to get around this and plot the values from each contact condition individually?

Thanks,
Adam

[maas]

Hi Adam,

This is a known issue and there is currently no way to extract the data from the individual contact surfaces in PostView (or FEBioStudio). The only work-around is to avoid the reuse of surfaces in multiple contact interfaces. Perhaps you can combine the three contact interfaces into a single interface by selecting smaller areas of faces and assigning them to either the primary or secondary contact interface. Let me know if this is not feasible though.

On my end, I'll take another look and see if there is way to separate the data or perhaps combine them in a meaningful way in PostView/FEBioStudio.

Best,

Steve

[agalloy]

Thanks for the quick reply!

I don't think putting everything into one interface will work. For context, I am modeling the left lung going from end inhalation to end exhalation. I have a shell mesh that represents the chestwall with displacements prescribed to it to drive the simulation. Inside the chestwall, I have two solid objects representing the two lobes of the lung to allow sliding between lobes as the chest cavity changes shape.

I plan to rerun the experiment with friction between the two lobes (but not between the chest wall and lobes) so I will need at least two contact interfaces: one with friction and one without. I also would like to evaluate the contact between lobes with two passes since the material properties are identical, but use only a single pass for the chestwall-lobe interface since the chestwall will have it's displacements prescribed. It's possible my second concern isn't that important for getting accurate, stable results though.

As of now, my plan was to only use the different contact values to help with debugging my model. They are not necessarily an end goal of the simulation, so if there isn't a good way to retrieve this information then I can probably work around it. That being said, I am willing to do some additional post-processing using a program like Matlab, Tecplot, etc. if you think there might be a way to retrieve this information using these more flexible tools.

-Adam