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Title |
Application of Damage Index for Limit State Evaluation of a Steel Pipe Tee
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Authors |
김성완(Sung-Wan Kim) ; 윤다운(Da-Woon Yun) ; 전법규(Bub-Gyu Jeon) ; 김성도(Seong-Do Kim) |
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DOI |
https://doi.org/10.11112/jksmi.2022.26.4.30 |
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Keywords |
손상지수; 손상모델; 저주기 피로; 강재 배관 Tee Damage index; Damage model; Low-cycle fatigue; Steel pipe tee |
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Abstract |
Maintaining structural integrity of major apparatuses in a nuclear power plant, including piping system, is recognized as a critical safety issue. The integrity of piping system is also a critical matter related to the safety of a nuclear power plant. The actual failure mode of a piping system due to a seismic load is the leakage due to a fatigue crack, and the structural damage mechanism is the low-cycle fatigue due to large relative displacement that may cause plastic deformation. In this study, in-plane cyclic loading tests were conducted under various constant amplitudes using specimens composed of steel straight pipes and a steel pipe tee in the piping system of a nuclear power plant. The loading amplitude was increased to consider the relative displacement generated in the piping system under seismic loads, and the test was conducted until leakage, which is the limit state of the steel pipe tee, occurred due to fatigue cracks. The limit state of the steel pipe tee was expressed using a damage model based on the damage index that used the force?displacement relationship. As a result, it was confirmed that the limit state of the steel pipe tee can be quantitatively expressed using the damage index.
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