摘要

The optical method of digital gradient sensing is used to the study of fracture characteristics. Fracture experiments are performed on PMMA specimens with different offset crack under three-point-bending, which is appropriate for mixed-mode fracture analysis. The full-field displacements around the crack-tip are used to study the fracture characteristics such as evaluation of deformation field, crack tip stress gradients, and crack initiation. Mixed-mode stress intensity factors and crack tip location are calculated simultaneously from DGS data by fitting the analytically angular deflections (or in-plane gradients of stresses) field using the method of nonlinear least-squares and are in good agreement with finite element results.