The nonlinear Burgers model has seven independent parameters, i.e., *E*, *ν*, *C*_{s}, *m*_{s}, *C*_{t}, *m*_{t}, and *t*_{ε}. In general, the nanoindentation load–displacement output is not influenced by the Poisson's ratio, *ν* [39–41]. Therefore, in order to keep the number of independent parameters to a minimum, *ν* was given a constant value of 0.34 and was not included in the sensitivity analysis scheme.