Figure 4.

Application of the methodology to obtain the onset of necking strains for a biaxial strain (BS) Nakajima specimen of PC with 1 mm of thickness. (a) The geometry of the specimens and identification of the section perpendicular to the failure region and selected points along its length. (b) Major strain (left) and surface shape (right) of the specimens’ failure area obtained by the DIC system. (c) Experimental time evolution of the major strain along the points of the selected section. (d) Time-dependent approach application. (e) Z-displacement along the selected section. (f) The spatial derivative of Z-displacement along the selected section.