Peridynamics enabled digital image correlation for tracking crack paths

This study combines peridynamic differential operator (PDDO), digital image correlation (DIC) and the Strain Compatibility Functional (SCF) method to track crack paths. DIC provides the full-field displacements at pixel accuracy by matching digital image sub-region of the specimen surface before and after deformation using correlation functions. The PDDO is applied to the deformation field to determine the strain field and the associated SCF. In presence of a crack, the strain field of a deformed body does not satisfy the strain compatibility condition due to the crack-induced discontinuity. Following the SCF method, a regression technique is applied in the region where the strain compatibility is violated to determine the crack presence, shape and its resulting path. The accuracy of this approach is first verified by considering three different DIC challenge data sets presented by the Society of Experimental Mechanics (SEM). Concerning crack path detection, the approach is first applied to the numerically generated deformation fields corresponding to pre-existing crack configurations. Subsequently, it is applied to the measured deformation fields corresponding to experimentally induced crack propagation. All these examples indicate that the present approach successfully detects the crack paths.