This paper presents results of experimental and numerical analysis studies to investigate the relationship between J and CTOD and assess whether they are, indeed, both suitable elastic-plastic fracture characterizing parameters. Detailed elastic-plastic finite element analyses were undertaken for SE(B) specimens with a/W ratios of 0.1, 0.2, 0.3 and 0.5. Analyses were performed for a range of material stress-strain curves and yield strength levels to determine the influence of work hardening and yield strength on the J-CTOD relationship.
It was found that: 1. The standard CTOD estimation procedure can give rise to significant errors in the predicted CTOD for high work hardening materials (σTS/σYS > 1.5) .2. For SE(B) specimens, the following J-CTOD correlation can be used to relate J to CTOD