ANSYS static structural help : Bodies Overlapping

[BigredIRL]

Hi,
I'm looking to make a model of Equal channel angular extrusion (pressing) using static structural in ANSYS. Something similar to the videos below.

http://www.youtube.com/watch?v=TsTjMXLmTao

http://www.youtube.com/watch?v=N1UUMGgZ8mM

I am having a hard time getting my deforming billet to follow the die path and not to overlap into the die body.

http://imgur.com/a/yGqd4

The second image here shows the deforming billet overlapping into the die which it shouldn't do.
Does anyone have any suggestions as to how to fix this?

thanks

 

[rickfischer51]

If you reduce the contact stiffness to aid convergence, and get a lot of penetration, and if the penetration is larger than the pinball diameter, I think the contact can exit the back of the target and release. And, ANSYS used to automatically reduce contact stiffness when plasticity was present. Not sure if it still does, I think there may have been a change recently. With no plasticity, FKN=1. With plasticity, FKN=.01, I think.

Rick Fischer
Principal Engineer
Argonne National Laboratory