Stress intensity factor interaction of subsurface flaws under notches

切欠底の内部欠陥の応力拡大係数の干渉

長谷川 邦夫; Dulieu, P.*; Lacroix, V.*

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

切欠底にある内部欠陥は、応力集中のため応力拡大係数の干渉効果が大きい。このため、内部欠陥は、切欠底から離れた位置で表面欠陥に置き換える必要がある。本論文は、応力集中場の応力拡大係数の干渉を示し、この干渉効果を基に切欠底に円欠陥があるときの接近性基準を提案するものである。

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.