• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.20 no.2
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• pp.115-121
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• 2024

In this study, the influencing factors of the four simplified elastic-plastic analysis methods (ASME B&PV Code Sec. III NB, ASME Code Cases N-779, N-904 and JSME EPD Code Case) for thermal fatigue loading were investigated via FE analysis of a simulated specimen. As expected, the ASME B&PV Code Sec. III NB method is the most conservative, because it applies the same K_e-factor to both primary and secondary stresses. The JSME EPD Code Case predicts a fatigue life 1 to 2 times longer than the ASME Code Sec. III method, depending on the restraint condition. The Code Case N-904 predicts a fatigue life 1 to 5 times longer. Finally, the Code Case N-779 provides the greatest reduction in conservatism, with a predicted fatigue life 3 to 7 times longer than the ASME Code Sec. III method.