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Journal Articles

Stress intensity factor interaction of subsurface flaws under notches

Hasegawa, Kunio; Dulieu, P.*; Lacroix, V.*

Proceedings of 2017 ASME Pressure Vessels and Piping Conference (PVP 2017) (CD-ROM), 5 Pages, 2017/07

The stress intensity factors of the subsurface flaws are affected by the stress concentrations caused by the notches. The interaction of stress intensity factor increases with increasing stress concentration factor and decreasing the ligament distance between the tips of the subsurface flaws and the notches for a given notch width. Such subsurface flaws shall be transformed to surface flaws at far distance of the notch tips for conservative evaluations. This paper shows the interactions of stress intensity factors of subsurface flaws under stress concentration fields. Based on the interaction, a flaw-to-surface proximity criterion for a circular flaw is proposed under the stress concentration field induced by a notch.

Journal Articles

Notch toughness evaluation of diffusion-bonded joint of alumina dispersion-strengthened copper to stainless steel

Nishi, Hiroshi

Fusion Engineering and Design, 81(1-7), p.269 - 274, 2006/02

https://doi.org/10.1016/j.fusengdes.2005.07.011

Times Cited Count：4 Percentile：30.68(Nuclear Science & Technology)

Tensile strength of the diffusion bonded joint was as large as that of Alumina dispersion-strengthened copper (DS Cu), however, the Charpy absorbed energy of the joint was considerably lower than that of DS Cu. Instrumented Charpy impact test and slow-bend Charpy test of diffusion bonded joints were performed to clarify the degradation of Charpy absorbed energy. Elasto-plastic analyses were also carried out in order to study the deformation behavior of the tensile and V-notched specimens for joints. As the results, the fracture behaviors of the impact and slow-bend tests were almost the same. Elasto-plastic analyses showed that the maximum strain occurred at the DS Cu apart from the interface for tensile specimen, however, the strain concentrated at the DS Cu near the interface for the notched specimen. This strain concentration arose from the mechanical heterogeneity between stainless steel and DS Cu in the bonded zone and attributed to the degradation of the absorbed energy of the joints.

Journal Articles