Naming of an "Epsilon Dot Zero" And a "Reference Strain Rate" of J-C Parameters in Abaqus/Explicit

Hello,

 
I'm a little bit confused with a naming convention of strain rates of Johnson-Cook plasticity and damage model in Abaqus. In J-C equations there are two parameters:  

• ε^.₀ (epsilon dot zero) known as a reference strain rate which has the value of 1 s^-1,
• ε^. (epsilon dot) known as the plastic strain rate or the effective strain rate [s^-1].

In Abaqus (Edit Material window), there are two parameters with the same(?) name:

• Mechanical -> Damage for Ductile Metals -> Jonhson-Cook Damage: parameter Reference Strain Rate,
• Mechanical -> Plasticity -> Plastic; Suboptions -> Rate Dependent -> Hardening -> Johnson-Cook: parameter Epsilon dot zero.

As you can see, it's not clear (at least for me) to decide which of the parameters is real reference strain rate. Could you help me which one of two parameters mentioned above is the ε^.₀ (epsilon dot zero - reference strain rate) from the J-C equation and hence which one should be set to 1 s^-1?

Regards, M. Madaj.