Investigation on the rotational deformation of SEB specimens with various crack length to width ratio

摘要

A new CTOD calculation formula was proposed by using a correction factor for the blunted crack tip in the authors' previous report[Kawabata et al(2016)], and the calculated CTOD by the formula significantly corresponded to the actual CTOD obtained by FE analysis in the wide range of specimen thicknesses. However, the use of the CTOD formula is limited to the frequently used crack depth-to-width ratio, a_0/W, between 0.45 and 0.55, and this does not satisfy a strong demand for wider a_0/W range. Meanwhile, ISO15653 covers a wider range of a_0/W between 0.10 and 0.70, where J-based CTOD calculation formula has been specified in the annex-E of ISO15653. In this context, the plastic hinge model was investigated for a_0/W between 0.05 and 0.70 by using FE analysis, and the analytical deformation of SEB specimens revealed that the plastic hinge model was applicable to the specimens even though their a_0/W were out of the frequently used a_0/W range from 0.45 and 0.55. Their rotational center points were almost steady when changing the applied load and the work hardening coefficient.