Viscoelastic properties

[fxue]

Hi guys,

I'm trying to assign viscoelastic material properties to a part of my model. By searching from the literatures, I've collected some parameters that were achieved from creep tests on the material. These parameters are: effective viscosity, relaxation time and shear constant. Could anyone give me some ideas how to assign these parameters, or are these parameters sufficient enough for assigning the viscoelasticity? Many thanks.

Feng

 

[yanger11]

Feng,

In the past when I have defined viscoelastic material models I created a table from the viscoelastic parameters of the modulus over time. ABAQUS manual has a good explanation of how to enter the viscoelastic data

 

[phiga2]

Feng,

if you're looking for a rubbery material, you should consider first a suitable strain energy function (SEF) (or stored energy function (SEF), they're the same).

e.g. The simplest SEF is the neo-hookean SEF, which describes the stress strain behaviour well for the first part of your stress-strain curve (perfect for low strains), however it fails at large strains (200-300%). There should be a lot of literature on it. The higher the order of your SEF, the more complex it is and describes the model better, however, e.g. some high order SEF's fail to describe the very low strains acurately. So it depends a bit what you're actually doing.

(All above is defined as "hyperelastic")

After this you can consider the viscoelastic response, which can be defined e.g. by relaxation test data from a shear test. These parameters, or test data go in the "viscoelastic" option.