Hyperelastic and viscoelastic parameters

[xsrose376]

I’m doing elastomer compression simulation now. The elastomer is rate dependent. Now, I have two experimental curves: one is the stress relaxation curve at the deflection rate is 360mils/min. The other curve is deflection-pressure curve at the deflection rate is 10mils/min.

I want use hyperelastic+viscoelastic material model for the simulation. Now, I do the simulation like this:
Step1. For viscoelastic, I got prony series through fit stress relaxation curve in ANSYS.
Step2. For hyperleastic, I use 2 term Moony-Rivlin model. Because I don’t know the exact C10,C01, I input two estimated values for C10 and C01.
Step3. Compression simulation in ANSYS by using above material parameters. From the simulation, I can get calculated pressure-deflection curve. Adjust C10 and C01 to let the calculated curve match the experimental curve. Then can get the C10 and C01.

Is there any problem of my method? I just want to get both hyperelastic and viscoelastic parameters.

[Jorgen]

I don't see anything wrong. Just keep in mind that the Mooney-Rivlin model is best calibrated using experimental data for more than one loading mode.

- Jorgen

[xsrose376]

Can i use the experimental deflection-pressure curve to fit M-R parameters?

[Jorgen]

Yes, you should be able to use any experimental load deflection curve.

-Jorgen

[xsrose376]

But, I'm not sure if we can regard the deflection-pressure curve as stress-strain curve.

[Jorgen]

Well, yes. You cannot use a deflection-pressure curve for almost anything
You need to convert it to stress-strain first.