Application of digital speckle correlation method to measure fracture toughness of foil material

In this paper, the digital speckle correlation method (DSCM) is selected as the experimental means to calculate the J integral of foil material. The deformation fields in the crack tip region are measured and their contour maps are shown. The formula using deformed field to calculate J integral is derived. Through calculating J integral of foil material by the DSCM, it is shown that this experimental method is a useful test technique in studying the mechanical behavior of film or foil materials.