Abstract
A preferable failure assessment diagram (FAD) is recommended in the latest CEGB R6 Rev. 3, depending on the categories of assessment. However, FAD defined by the applied stress/net section plastic collapse stress ratio (Lr) as the abscissa is not necessarily useful for assessing the integrity of structures suffering the strain over the full yielding, for example, in the case of high ductile structual components.
In this paper, a modified FAD for the estimation of ductile fracture behavior is proposed based on the concept of overall strain. For the purpose of confirming the validation of the proposed FAD experimentally, the FAD is compared with the reference data of fracture tests using center cracked panel specimens and compact tension specimens of 304 austenitic stainless steel at room temperature and 550°C. It is concluded that the proposed FAD can express the ductile fracture behavior in the strain region over the full yielding more reliably than the conventional R6 FAD.
