Question on the Modelling of Elastomers (Perfluoroelastomer)

[kuddy]

Jorgen,

Please am just new in the field of Elastomer modelling. I work with MSc Marc, and am quite confused on how to implement material properties for my polymer.
1. How is the C10 parameter (for Neo-Hookean) in MSc Marc calculated? is it Shear Modulus/2 ?
2. How important is the Bulk Modulus for elastomer analysis. Because in MSC. Marc , when you choose for instance Mooney, you have a button to fill in the bulk modulus and mass density
3. Do you have an idea of any experimental data for a Perfluoroelastomer?
4. I want to use the DMA for characterising this elastomer, do you think it will be helpful?
5. In my simulation, the elastomer is attached to a rigid body and it is used to press against some structures beneath it. I guess I would need to use uniaxial deformation mode , am I correct?

[Jorgen]

(1) Yes, C10 is the same as shear modulus / 2

(2) The bulk modulus is typically not important. The only exception is for elastomer components that are highly confined, for example o-rings.

(3) I don't think I have experimental data for that class of materials. Have you performed a literature search?

(4) DMA is a good tool. Depending on your application you might also want o complement that with uniaxial tension or compression.

(5) If the strains are "really small" then DMA might be sufficient. It would be nice to also have uniaxial data.

- Jorgen

[kuddy]

Jorgen,
Thank you for your reply.
So far I have not been able to find any experimental data for Perfluoroelastomers.
I still have a question.
1) So if I use my DMA test data which will be E-modulus against temperature, can I now convert it directly to Shear Modulus by using the equation that: Shear Modulus= E/2(1+poisson)?

I do want to thank you once more for this very valuable forum that you have created.

[Jorgen]

Yes, you can calculate the shear modulus using that equation :p