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Nakamura, Izumi*; Otani, Akihito*; Okuda, Yukihiko; Watakabe, Tomoyoshi; Takito, Kiyotaka; Okuda, Takahiro; Shimazu, Ryuya*; Sakai, Michiya*; Shibutani, Tadahiro*; Shiratori, Masaki*
Dai-10-Kai Kozobutsu No Anzensei, Shinraisei Ni Kansuru Kokunai Shimpojiumu (JCOSSAR2023) Koen Rombunshu (Internet), p.143 - 149, 2023/10
In 2019, the JSME Code Case for seismic design of nuclear power plant piping systems was published. The Code Case provides the strain-based fatigue criteria and detailed inelastic response analysis procedure as an alternative design rule to the current seismic design, which is based on the stress evaluation by elastic response analysis. In 2022, it was approved to revise the Code Case with improving the cycle counting method for fatigue evaluation to the Rain flow method. In addition, the discussion to incorporate the elastic-plastic behavior of support structures is now in progress for the next revision of the Code Case. This paper discusses the contents and background of the 2022 revision, the progress of the next revision, and future tasks.
Ueda, Shuzo
JAERI-M 87-027, 179 Pages, 1987/03
no abstracts in English
Morishita, Masaki; Otani, Akihito*
no journal, ,
The JSME Code Case N-CC-008 provides design rules for piping seismic design by inelastic response analysis and strain-based fatigue criteria. The Code Case uses the Rainflow method for cycle counting. The Rainflow method is used for identifying pairs of peaks/valleys of the representative strain and their occurrence times. On the other hand, ASME Code reads "The Rainflow cycle counting method is recommended but not applicable for non-proportional loading." The authors analyzed the behavior of multi-axial strain of piping systems to test the non-proportionality. The analysis results showed that the multi-axial strain in piping systems induced by seismic excitation is almost proportional. Based on this result, the authors concluded that the Rainflow cycle counting method is well applicable for the piping seismic fatigue evaluation. In addition to these numerical analyses with the IS method, some discussions are also made in this paper from the viewpoint of the relation between vibration mode and strain components to support the conclusion that the piping strain by seismic loads is proportional.
