Bhargava Sista
Ansys Employee

You can use the shear relaxation test to calculate the Prony series constants. These properties are in time-domain so you'll need to convert them into frequency-domain using the following equations, which is nothing but calculating the storage and the loss modulus. 

You'll need to define a starting and the ending frequency to calculate these quantities. Once you do this conversion, you can input these properties into ANSYS Mechanical using command snippets.