Analysis of standard fracture toughness test based on digital image correlation data

This paper deals with an experimental methodology based on the 2D Digital Image Correlation method for precise full-field in-plane stress-strain analysis of a region containing a crack. The presented methodology is employed as a supporting and comparative method for the standard J-integral testing defined by the ASTM. The methodology utilizing the DIC-based displacements for a subsequent evaluation of strain, stress and final extraction of the J-integral from its definition. This J-integral is compared with the value obtained by the ASTM standard and with the value obtained by the DIC-based CTOD measurement. Several techniques improving the conventional DIC and data post-processing are proposed to achieve reliable full-field strain/stress results. A direct comparison between the experimental and FEM full-field results is carried out.