Time step for BB model

Hello everyone,

In my team, we implemented the Bergstrom Boyce model in a in-house 3D FE code to simulate the mechanical behavior of TPE and adhesives. Even though we implemented an implicit formulation with no restiction on the time step for the evolution law ( network) integration, we are looking for a "natural" time scale for the model to set up our simulations

My guess would be that it would depend on the constitutive parameters, but it might also be related to the strain rate dynamics of the problem at stake. 

I am struggling to find any literature on such a topic, so if anyone has a clue on the topic, it would be appreciated 

Thanks, by advance,

Quentin