Paul,
I agree with Chris Kaswer and Randy Speed that the odd picture is most likely due to the scaling factor, however, still wanted to add my 2 cents.
The matter is that the Fastener feature does not automatically create Contact Interface between the parts, rather, it uses a so called Separation Spring (linear, and very stiff) to enforce the non-penetration condition between the parts, and it does it only over 2 small annular areas (called Separation Areas), concentric to the fastener hole. And it creates Free Interface on the rest of the contacting area.
The point is:
a) The Separation Spring is a very approximate way to enforce non-penetration (but it's a lot cheaper than Contact in terms of runtime), thereforeyou may seesome interpenetration even on those annular "separation" areas
b) and Free Interface fully allows interpenetration beyoned the separation areas
I know it all may sound complicated and confusing, it's just thata moredetailed explanation how the Fastener feature works would takes quite a few pages and pictures. I would probably recommend contacting PTC directly, I know they have a kind of a whitepaper on the subject.
Lastly, you can deactivate this very approximate"Separation Spring" thing by manually creating Contact Interface between the parts, then the interpenetration troubles, if any,should go away.
Hope this helps a bit.
Yuri Apanovitch
(I don't intend to make this all even more confusing, but be aware that most if not all commercially available contact solvers actually allow a tiny bit of interpenetration too).
--- On Thu, 4/28/11, Korenkiewicz, Paul <-> wrote: