Im having a bit of trouble trying to develop a viscoelastic material model to couple with my hyperelastic model. I already have experimental stress-time curves for my material. I then simply calculated the modulus at each stress value for a particular time, and then determined the shear modulus by dividing the modulus by 3 (general approximation). Then I put all of this data in the curve fitting tool for viscoelastic material modeling in ANSYS. The time I put in was basically in seconds with 5 seconds intervals. Only room temperature curve was obtained.
Now I am not clear about the results I am getting for the curve fit. No matter what options I choose (Shear, Bulk, Shift), I always get the plot as shown in the attached image:
Please advise where I could be going wrong. Is it the initial calculation? Or am I doing something wrong with the fitting?