Using strain rate as a variable

Hi All,

I am using COMSOL 4.2 to simulate plastic deformation of aluminum via a dynamic-viscosity approximation. The approximation requires strain rate.

My question is how do I access strain rate for the calculation? It was fairly easy is FLUENT but I am having difficulty finding the parameter in COMSOL. I have tried using the equation view and plotting/probing functions to identify it without any luck.


Thanks for the help.