Prony Series fitting for a broad frequency range

Hi,

I have the DMTA data for storage and loss modulus curves with frequency on x-axis. 
I want to ask how do we know the frequency range for which we have to fit the equations of loss and storage modulus to the data to get the right prony terms for my simulation.

My simulation is a simple impact of a rigid body on the elastomer.

Does the frequency range for the fitting correspond to my loading curve frequency of simulation, or the timestep of my simulation or anything else?

Best Regards!