Vinayak Vipradas
Ansys Employee

The initial values of the coefficients can come from examining the function that defines the model to which you are attempting to compare/fit your data. For most hyperelastic models, 1 or -1 is a good starting point; however, coefficient values can vary greatly depending on the model chosen. The Gent model, for example, provides good fit with initial coefficient values as high as 1000.

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