Digital gradient sensing measurement applied in static fracture mechanics experiments

In order to study the local deformation field of crack tip and fracture characteristics in fracture mechanics, static fracture tests of the limited-width polymethyl methacrylate specimen with center-crack were carried out with digital gradient sensing method. Speckle patterns under different states of stress near the crack tip were recorded by CCD in the experiment. Angular deflection was obtained by digital image correlation method and stress intensity factor in mode Ⅰ crack was extracted by angular deflection. It shows that the stress intensity factor calculated by digital gradient sensing measurement method is consistent with theoretical results.