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Title |
Definition of Limit Load for Damage Index Evaluation of 3-Inch Steel Pipe Elbows in Nuclear Power Plants
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Authors |
김성완(Sung-Wan Kim) ; 전법규(Bub-Gyu Jeon) ; 장성진(Sung-Jin Chang) ; 정영수(Young-Soo Jeong) ; 박동욱(Dong-Uk Park) |
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DOI |
https://doi.org/10.11112/jksmi.2026.30.3.9 |
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Keywords |
손상지수; 손상모델; 한계상태평가; 강재 배관 엘보; 항복점 Damage index; Damage model; Limit state evaluation; Steel pipe elbow; Yield point |
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Abstract |
Steel pipe elbows in the piping systems of nuclear power plants are vulnerable to seismic loads, thus requiring critical consideration in seismic safety assessments. The limit state, defined as the occurrence of leakage due to fatigue cracking in steel pipe elbows, was quantitatively expressed using a damage index. In this study, this limit state was quantified using a damage model that accounts for both non-cumulative deformation and cumulative energy dissipation. Furthermore, the limit load was applied as the yield point criterion to reduce the variability in the damage index arising from different yield point definitions. For the limit state evaluation, constant-amplitude displacement loads were applied to the steel pipe elbows in the in-plane direction. The damage indices were calculated by applying both individual and representative yield points to the damage model, and the effect of the variability caused by the yield point definitions on the limit state evaluation was analyzed. The results confirmed that the damage index based on the representative yield point can quantitatively evaluate the limit state of steel pipe elbows.
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