Rubber contraction simulation

[scarules2006]

Hello dear friends,
I have some issues, sometimes, when I try to simulate the contraction of metal/rubber bodies after molding. Right now I'm using the isotropic secant coefficient of thermal expansion, in Ansys 16. Sometimes by using this coefficient my results are according to reality but sometimes they aren't. Has anyone here tried to simulate the rubber contraction in Ansys? If yes, have you obtained good results? And again, if the answer is still yes, how you've done that?
Thank you!

 

[scarules2006]

Anyone?

 

[scarules2006]

Any ideas? Is there any other way to simulate the thermal expansion in Ansys? Thank you!

 

[rstupplebeen]

I have performed similar simulations in Abaqus. I assume the workflow would be similar for you in Ansys.

For my application we were thermally curing our product. Upon removal of the part shrinking and deformation was occurring. The simulation went through the following steps.

1. Initial geometry of cold mold and negative of mold modeled.
2. Heat up mold causing expansion due to CTE
3. Force the part to expand with the mold
4. Anneal the part
5. Cool allowing plastic deformation in part
6. Open mold
7. Remove part
8. Measure part

Hopefully this will parallel your needs enough to be useful.

Rob Stupplebeen

http://www.optimaldevice.com

https://sites.google.com/site/robertkstupplebeen/

 

[scarules2006]

Thank you Rob for your interest in helping me. My problem is the results I obtain, sometimes are ok but sometimes aren't. I'm thinking, maybe, this simple coefficient isn't enough for rubber/metal parts. If I have a simple geometry, let's say a rubber cylinder the results are according to reality but if I use a bushing made of rubber steel bonded to each other the results aren't always(in some cases are ok) according to reality. I was hoping that someone here encountered the same problem and solved it somehow.
Thank you again!

 

[boyze]

molding pressure can affect the result. In fact, molding pressure is used to counter shrinkage in some cases.

Have Fun!

James A. Pike

http://www.xl4sim.com

http://www.erieztechnologies.com

 

[scarules2006]

Ok,
So there are many factors which affect this contraction( I was aware of that).
Can I input them somehow, beside, the isotropic secant coefficient of thermal expansion in a simulation in Ansys so the results would be more accurate?
Has anyone tried this and succeeded? I know that it matters the temperature of molding, the time in which the molding is done, etc.
Thank you all!
Any idea is more than appreciated!