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In this work are presented the results of a set of tensile tests in which has been evaluated the behaviour of the
triaxiality ratio during increasing stress and strain on differently notched specimens. The shape of the specimens
profiles have been video recorded and analized in order to perform measurements and calculations for the necking
profile radius. Some considerations allowed to build a reasonable correlation between the profiles radii and the
natural strains for each specimen tested. According to the Bridgman [1] solution for stress fields in the necking
region, has been evaluated the triaxiality factor at various strains, showing that, neverthless the load direction does
not vary during tensile tests, the TF does not remain constant as it’s assumed in some continuous damage models
considered below, because geometrical modifications may affect the stress distribution as well as the load direction
ones. Furthermore has been checked the sensitivity of some damage evolution laws with respect to the presumed TF
variability.