axisymmetric model with contact-compatible mesh?

[nlinesk8s]

I'm working on an axisymmetric model of a rod and locking collar with multiple teeth. This resembles a nut and bolt, but the "threads" of the bolt aren't helical.

I've set up contact connections between the teeth faces, but when I do a check run of the model, I get an error saying that contact is not possible "...because it is not possible for any of the elements on one side of the contact region to contact any of the elements on the other side."

If I look at the elements created on both parts, nodes don't line up in the areas of contact. I had tried this as a 3d model, and there was a pick box at one point to "create compatible mesh", but I don't see that in the axisymmetric model setup anywhere.

How do I get common nodes on the two parts so the contacts will work?

thx,

 

[jvian]

It may help if you include some kind of pictures to show what you are trying to do. Creating node to node element mesh probably won't fix your problem. To me it appears you have improperly defined contacts not an improperly defined mesh. This is a common error when I have tried using auto-detect contact pairs or when I default to 'component-component' contacts and is usually solved by manually defining the contact regions. For me the error occurs when two perpendicular surfaces are collected or when opposite regions of opposing cylindrical surfaces are collected. Also make sure you are not dealing with gaps in the surfaces.

Just some thoughts and hope that helps,

- J -

 

[shaun8567]

+1 for jvian's response. Change your model definition to free as the default, ensure that the edges where you to apply a contact interface are initially in contact, and apply said contact interface.

 

[nlinesk8s]

I was able to fix my problem. The issue is similar to mating straight-sided gears. Only a part of the each gear face is in contact. I slightly undercut my mating faces to that the contact areas exactly matched. The contact connections then worked.

For my purposes this was good enough. However, there are real situations where a mismatch of contact surfaces is desirable. In those cases contact would not work.