The Bergstrom-Boyce (BB) model is, in my opinion, the best simple non-linear viscoelastic material model for rubber-like materials. The popularity of the Bergstrom-Boyce model is evident by how many commercial FE codes have implemented it as a built-in feature. Here’s a partial list: Abaqus, ANSYS, ADINA, Altair Radioss™, MSC.Marc, and LS-DYNA. I described the theory of the BB-model in another article, here I will visually demonstrate how the different material parameters of the BB-model influence the predicted stress-strain response.
The figures shown here were generated using MCalibration®, which is excellent for these types of studies.