In an article found:  Conventional procedures to calibrate constitutive parameters entail the use of standard specimens (such as smooth round bars or flats), in which the stress/strain states are homogenous, allowing for estimation of stress strain directly from the test data (based on specimen cross-section and gage length), and subsequent calibration of the constitutive model from the stress-strain histories. However, these specimens show some form of localization (necking under tension or buckling under compression) at strains in the range of 10–15% (0.1 to 0.15), which is significantly lower than strains at which ductile fracture usually initiates (0–0.75–1.0). Consequently, these specimens cannot be used to accurately calibrate constitutive moover strain ranges that control ductile fracture (0.5–1.0 – Kanvinde and Deierlein [3]). This necessitates the use of non-standard specimens (such as Cylindrically Notched Tension, CNT – see Fig. 3) in conjunction with complementary CFE simulations to back-calculate model parameters that minimize error between the load deformation (rather than stress-strain) histories.