Transactions of the Korean Society of Pressure Vessels and Piping (한국압력기기공학회 논문집)

Korean Society of Pressure Vessels and Piping (한국압력기기공학회)
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Strain-based Damage Evaluation of Specimens under Large Seismic Loads

대형 지진하중에 대한 시편의 변형률기반 손상평가

  • 권형도 (한국수력원자력(주) 중앙연구원) ;
  • 허은주 (한국수력원자력(주) 중앙연구원) ;
  • 이종민 (고려대학교 기계공학과) ;
  • 김진원 (조선대학교 원자력공학과)
  • Received : 2018.10.25
  • Accepted : 2018.11.28
  • Published : 2018.12.30
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Abstract

In this paper, specimen tests with simulated large seismic conditions have been carried out to investigate damage characteristics such as structural deformation and crack initiation under seismic loading. The mechanical behavior of the specimens is predicted by numerical simulations and the strain-based damage evaluations are performed. Finite element analyses of the specimens under the simulated seismic loading at room and operating temperatures were carried out for low alloy steel and stainless steel materials. Peak strain amplitude, cumulative fatigue damage and cumulative strain limit damage are calculated considering the nature of cyclic loading. In all cases, the allowable damage criteria are exceeded at the time of observing cracks visually in the tests. Therefore, it is confirmed that the material behavior due to the large seismic loads can be predicted by the numerical method and the structural damage of the materials can be evaluated conservatively based on the strain criteria.

Keywords

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Fig. 1 The specimen used in the experiment

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Fig. 2 Sample time history of the input load-line displacement

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Fig. 3 Sensitivity check for mesh sizes and element types

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Fig. 4 Position for damage evaluation at the maximum equivalent plastic strain (PEEQ)

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Fig. 5 Cumulative damage of SA508 Gr.3 Cl.1

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Fig. 6 Cumulative damage of SA312 TP316

Table 1 Number of cycles at detecting a crack under cyclic loading

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Table 2 Comparison of maximum loads between analyses and experiments

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Table 3 Results of the strain-based damage evaluation for the SA508 Gr.3 Cl.3

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Table 4 Results of the strain-based damage evaluation for the SA312 TP316

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