Defining viscoelastosity parameters in Ansys

Hello all,

I want to define a viscoelastic model in Ansys that behaves according to Maxwell's viscoelastisity model. My goal is to find the viscoelastic parameter η, in order to gain the same curve with the one I got from the tensile experiment. 

My data include: stress-strain curve, Young modulus and poisson's ratio.

1) I've been thinking about assuming a value for η, selecting the 'prony shear relaxation' option and defining the 'Relaxation time' as: t=η/E. Is it correct?

And of course repeating this procedure until the graphs are the same.

2) Do you have any other idea about how to calculate the viscosity parameter from the data?

Thank you in advance!