ANSYS WB 15 - How do I combine hyper- and viscoelastic?
For my bachelorthesis i have to simulate different elastomers (NBR, FKM, EPDM,...).
I have a lot of test data, like creep and stress relaxation, Tensile testing or uniaxial compression.
Because FEA is completely new for me, i have to learn a lot of new thins.
My first goal was to recreate the tensile test, this works well. I know how to fit my Test Data to Models like Mooney-Rivlin or Yeoh.
Now i want to recreate the relaxation test, but when i want to create a material with hyperelastic(Mooney-Rivlin) AND viscoelastic(Prony-Shear) data, my Mooney-Rivlin Model gets crossed out and ANSYS suggests an isotropic elasticity.
so my question is : How can i combine hyper and viscoelastic Models?
And a second question : I determine the shear modulus for my viscoelastic Model by G(t) = E/(2*(1+ny)) , where ny = 0,49 and E = stress(t)/strain. But i dont know what the right units are. is it [MPa] for stress and [%] for strain?
Thanks a lot and greetings from germany,