Using contact to simulate flexible media between to rigids. How?

[opetrenko1]

this fell on me as an urgent task.
ANSYS Mechanical v. 12.1
I've got a long metal spiral pipe covered by a thick layer of "rubber". As pipe deforms (Thermal loads. This I did.) this thing first touch a rigid wall and then rubber deforms.

I want to setup a linear force vs. distance between pipe and the rigid wall to represent rubber compression.

How to do it?
I tried a spring, but it's attached to points, so when pipe merely slides along a wall a force occures. I need forse as a function of distance between a wall and a pipe - not between particular points.

Is there a way to setup some contact boundary condition to simulate this?

I will greatly appreciate any help. This is an urgent and important for me.

Please, be specific about all selections and options as I'm no expert in Ansys.
Thank you

P.S. same post starting with " does not show up when I'm logged out. That's probably the reson for 0 replies. So I repost. Thanks!

 

[kan123]

If your wall is flat and oriented in one of the coordinate axes planes, you should be able to use 1D longitudinal linear springs (COMBIN14) which would only record force in the direction normal to the wall. But this would also apply a force to your pipe when it is separated from the wall. The next best option is a node-to-node contact element (CONTAC52). This could be set up to apply little or no force when separated. You would set KN based on the stiffness of your rubber material. (If the displacement is too large for a linear approximation, you could then overlay additional elements with greater initial gaps to provide the nonlinear response.) A node-to-surface contact element (CONTA175) would probably be even better, but that is more complicated to set up.

 

[Elabbasi]

It seems that you are not directly modeling the rubber, and that's why you want the linear springs? If you explicitly model the rubber then there is no need for the spring, and you can just setup contact between the rubber and the rigid wall.

If you do need springs then use COMBIN14 as kan123 mentioned, and set it to act only in the direction normal to the wall. You also need to use the ILENGTH feature of this element (Keyopt(3)=1) to define the initial force-free length which in your case is the initial contact clearance.


Nagi Elabbasi

http://www.veryst.com

 

[opetrenko1]

kan123, Elabbasi,

Thank you for the help!
Can this be done in workbench?