Elimination of the effects of geometry on fracture toughness by continuous damage

摘要

Detailed crack tip stress and strain fields are generated for different plane strain fracture specimens. These fields are matched approximately by a tri-parameter characterization of (J, Q, k) in the microstructurally significant region of ductile material. Continuous damage mechanics and the crack tip field of (J, Q, z) are used to quantify constraints in different fracture speciemens and the effect of specimen configuration on the onset of crack growth. The relationships between the theoretical fracture toughness J_c~(HRR) (critical J integral value in HRR field) and the integral values of J in actual specimens are established by an assumption that fracture initiation occurs at the same damage values in both specimens and HRR field. An application to experimental data is explored in this paper.