Uniaxial compression test to determine Hyper-viscoelastic parameters
I have done few compression tests and used Abaqus-in built Material Evaluate option to determine viscoelastic parameters. The Prony parameters are in good agreement with the experimental data. Also, I tried fitting various Hyperelastic models in abaqus but only Neo Hookean Model is showing stable for all strains results. However, the Predicted curve is not same as experimental curve. As per the abaqus user manual, Abaqus is biased towards calibrating the material for lower strains and hence it was recommended to delete most lower strain values and keep more of high strain values (in my case 20% strain). Hence, I am following this recommendation.
Now, I am trying to validate the complete experiment in Abaqus but the results from FEA and experiment is not matching. Only the maximum force achieved is same. For relaxation I have noticed that the material has relaxed by 24% of the maximum force value in experiment but in simulation it is relaxing only by 10 %. I have attached the comparison files here from 0-10sec and 0-100sec for better viewing. (Note: it is the same experiment)
Can anyone help me to solve this problem ? I have tried so many things but nothing is working out.
You should switch to a better tool to calibrate the material model. Specifically, check out the [URL= http://polyumod.com/download ]MCalibration[/URL] software!