Polyurethane Modeling Coefficients

[Fra]

Hello everybody,

I'm a new entry in this forum and a new entry in the FEM world indeed.

What I have actually to perform is a FEM analysis on a big piece of polyurethane.

I don't know the material properties neither the exact mixture yet, I just "touched" it, and it's something like a strong rubber (like the rubber used in some solid wheels for small professional tools trolleys like in hospitals or similar).

The model I was thinking to use is the Mooney-Rivlin one. What I would need is a set of coefficients to start the analysis. :confused: (as a further step I'll eventually perform tests on material samples)

Can anyone of you please give me some idea about the Mooney-Rivlin coefficients values, where I can eventually find some reference for them, or finally give me any feedback on my idea to use the M-R model?

Thank you very much.

Fra

[Jluc]

Dear Fra,

I am working on the Polyurethane too. For the modeling, I have used a Yeoh model to simulate the hyperelasticity. If you have ABAQUS, there is an automatic fitting to find the parameters of your hyperelastic model. You could find enclosed a file that I have used for the automatic fitting in ABAQUS.
*HYPERELASTIC,name you put the name of your hyperelastic model (see ABAQUS manual)
*UNIAXIAL TEST DATA: you enter your tests data (here in compression)
and ABAQUS will give you the fitted parameters of your hyperelastic model.

The Bergström-Boyce model, taking into account the time dependency, is also available in ABAQUS and works well with Polyurethane.

Please find below an interesting article from Qi and Boyce on Polyurethane for tests and modeling:
H.J. Qi and M.C. Boyce, “Stress-strain behavior of thermoplastic polyurethanes”, Mechanics of Materials, Volume 37, Issue 8, Pages 817-839, 2005.

Thanks,
Jean-Luc