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Contact interaction not working for restart/import file

Contact interaction not working for restart/import file

Contact interaction not working for restart/import file

(OP)
I'm working on an explicit model, nitinol mesh inside a tube. I've completed the loading process in a previous analysis, and now I'm using it for the base of an import model to continue the analysis and release it against a piece of rubber. So, I've successfully brought everything in, ran it, and now I'm working on defining my rubber and re-running it now with the nitinol contacting the rubber. I have all of the surfaces of the new material defined, my interaction is using general contact:

** INTERACTIONS
**
** Interaction: Int-1
*Contact, op=NEW
*Contact Inclusions, ALL EXTERIOR
*Contact Property Assignment
, , contact

My nitinol still interacts with the tube just fine, but when I try pressing it against the rubber it's as if the rubber doesn't exist. There is absolutely no interaction between the nitinol and rubber. I don't know why, because explicit general contact should take care of this, right? What's going on?

RE: Contact interaction not working for restart/import file

Do you get a contact pressure larger than zero? What about COPEN? Also request the variable CSTATUS and look at that. You have to figure out, if the contact is there or not. If it is there and you get penetrations, then it would be a problem with the penalty stiffness. That could be scaled up if necessary.

RE: Contact interaction not working for restart/import file

(OP)
In the previous analyses I had not requested COPEN or CSTATUS. However, I was able to plot CPRESS on my rubber material, and it has non-zero values.

RE: Contact interaction not working for restart/import file

When there is CPRESS, then there is a working contact. So penetration might come from a penalty stiffness that is too low. That is quite unusual in Explicit, but possible.

Take a look at the section called "Contact controls for general contact in Abaqus/Explicit" in the Analysis Users Guide.

RE: Contact interaction not working for restart/import file

(OP)
I am coming back to this thread after trying a lot of things, and I'm still stumped. I do get a CPRESS value, but it's e-5, and hardly where I'd expect there to be any values. Any other thoughts of things to look at? I've tried defining contact pairs instead of relying on general contact, and still no luck. I've switched the master/slave orientation and no luck, tried hard contact and penalty stiffness - no luck.

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