strain energy and prony series

[AXS]

Hello

I have a question about rubber FEM under dynamic transient loading and large
strain

I use Msc MARC software for this simulation

This software allows me to describe the viscoelastic behaviour of rubber, using
Prony parameters of strain energy (but not the shear or young's mudulus)

Yet, i just have the shear modulus and young's modulus VS. frequency
I am able to find the Prony series parameters for those curves but not for the strain energy

Parameters of prony series are they the same for shear mudulus , Young's modulus
and strain energy????

If it is not the case, is these is a relation between energy and modulus????


Best regards

Pierre Perrot
pperrot@estia.fr

[Grant]

I don't use MARC much, but I always thought the various VISCEL model definition entries asked for the Prony series for G and K. That is how I read page 3-672 in Volume C of the 2005 documentation. You can get K from G and E using K=EG/(3(3G-E)).

[Jorgen]

First, why do you need an expression for the strain energy density?

Yes, there are equations for converting between strain energy and moduli. Typically you don't need to worry about the strain energy equations unless you are trying to implement a new hyperelastic model.

- Jorgen