A non-local stress fracture criterion accounting for the anisotropy of the fracture toughness

A comparative assessment between the maximum circumferential stress criterion and the non-local stress criterion applied to mixed mode fracture problems in wood is presented. Various attributes of the two fracture theories, such as the shear stress component acting on the critical plane, the non-singular term of the crack tip stress field and the angular distribution of the fracture toughness, are investigated for their impact on the mixed mode fracture behavior of wood. Predictions of the direction of crack propagation and the fracture locus are validated against experimental data available in the literature, with emphasis on results obtained from single edge-notched wood specimens subjected to on-axis biaxial loading and off-axis tensile and off-axis shear loading.