Creation/Simulation of Creased Part

[Cappie]

I'm making parts by perforating thin (3mil) plastic and folding along the perforations, it behaves very similar to folded paper. I would like to perform FEA and eventually fatigue analysis on these folds, but the solutions rarely solve and when they do it is apparent that the fold is not being treated as a crease. I've tried using the SolidWorks sheet metal tool as well as just knit surfaces to create the part and both yield incorrect results. Has anyone done something like this in SolidWorks before? Is there software that is better suited for this type of problem?

Thanks,
Cappie