Figure 1:

Schematic overview of the methods to assess the identifiability of model parameters. Briefly, (1) after implementing the constitutive models and selecting the baseline parameters based on the literature, (2) we conducted a multi-start nonlinear least squares (NLSQ) optimization by using randomly generated initial guesses; (3) we then assessed identifiability of the material parameters using two criteria, one based on the quality of the fit of axial stress (Criterion 1), and the other based on the prediction of the lateral strain (Criterion 2).