Creep Coefficients for Teflon (for FEA Analysis) 2

[g1a1]

I'm trying to perform a FEA analysis on Teflon as a valve seal. Can someone provide general creep coefficients for either Ansys or Cosmos?

 

[Demon3]

I have no values but in general PTFE is a soft material and I expect high creep. Probably not a great choice for a seal. Filled PTFE should have much lower creep though.

 

[Demon3]

One small comment. Be careful when looking for data on "Teflon". DuPont uses that tradename for 3 or 4 totally different polymers. You probably need data for PFTE.

 

[Demon3]

OK, i did a Google search

Creep values for PTFE in valves:

http://www.industry.net/industry/fi...01.html?id=128704&comp_id=0BKQW&base_region=*

Effect of fillers on PTFE (reduce creep):

http://www.texloc.com/closet/cl_ptfe-types.html

 

[g1a1]

Thanks Demon3 for all your help!

 

[Demon3]

We aim to please sir

 

[plastx]

This is an analysis in ABAQUS but has some great info for PTFE seals.

http://polymerfem.com/polymer_files/ABAQUS_Meeting_2005.pdf

 

[g1a1]

Thanks Plastx...Great Stuff!

 

[RvL04]

g1a1,

be careful with using some of those 'published' values; as Demon3 indicated in his first response they may not all refer to the same thing. What's to stop you from actaully getting your seal tested? I know there's lots of great labs out there (e.g. Axel) that would be happy to do a creep test (short term or long term) on a (Teflon) seal!

 

[chrich]

I did some rough "memory" tests on square profile PTFE lengths we use as seals. At temperature (100`C+), these seals were clamped up in a circle overnight, they retained the new shape reasonably well.
Don't know if you need to take this into account??