Small gaps in Mechanica models

[mdristy]

I have a simple Pro/E assembly (Wildfire 4.0) and two of
the parts in the assembly are separated by a tiny gap
(about .002"). This gap will close under the applied
loads, as parts elastically flex, and forces will then be
transmitted through the two parts. How do I model this
reality in Mechanica? I tried using Contact Interfaces
but it didn't work. The model ran but the two parts just
passed right through each other. (The Contact Interfaces
worked well for parts initially touching prior to the
application of loads.) Thanks!

 

[mgage2000]

did you turn contacts on by checking the nonlinear checkbox? Mechanica will automatically bond parts together that are initially touching.

 

[jimshaw]

mdristy,


I'm not familiar with mechanica as much as Ansys, but there should be a setting which determines the proximity of surfaces which the tool uses to bond them together. Ansys calls it the "pinball region". Find it and set it to .003", then it should acknowledge the surfaces as touching/contact.


You could also modify the geometry to remove the gap completely.


Lastly, you could explicitly create the contact pair (Technically it would be "no penetration", but you might be able to get away with bonded).


Sorry I can't give you a more detailed solution, but I hope this helps.


Jim
http://www.linkedin.com/in/shawengineering/