Session: CS-16-01 Fatigue and Ratcheting Issues in Pressure Vessel and Piping Design

Paper Number: 122943

122943 - Asme Cc N900 Revision Discussion（no1）effect of Triaxiality Factor on Allowable True Strain Amplitude 

　In 2019, ASME Section III and JSME published a remarkable code case (ASME CC N-900/JSME NC1 CC-008) regarding seismic design codes for piping by using elastic-plastic analysis.  As shown in  PVP2023-107170  "Seismic Design Method of Crossover Piping Across Building Isolation Boundary", while it would be clear that this case standard using elastic-plastic analysis allows for a reasonable seismic design of the piping, there are few examples of actual seismic design works by using this code case.  The reasons why the seismic evaluation method based on elastic-plastic analysis of piping has not been widely applied to actual design works include conservative strain-based criteria based on both Triaxiality Factor [TAF] and allowable true strain amplitude and narrow usage scope. Therefore, this paper provides with the results of studies on such as strain-based criteria based on assumed failure mode (fatigue failure or ductile collapse) of piping under earthquake, relationship between fatigue life and triaxiality factor [TAF] of pipe fittings, and allowable true strain amplitude to establish the seismic evaluation method based on elastic-plastic analysis of piping in actual seismic design works as technical issues related to ASME CC N900. Also, this is a follow-up of paper of PVP2023-107197"Elastic-Plastic Analysis for Crossover Piping by Using ASME Code Case N-900 and JSME CODE CASE NC-CC-008".

Presenting Author: Kenichi Shibukuwa IHI Corporation

Presenting Author Biography: Kenichi Shibukuwa is a manager at IHI Corporation in Japan. His work focuses specifically on management of maintenance and construction project for Domestic Nuclear Power Plant. He has a lot of expertise in the piping engineering of nuclear power plant for 33 years. Also, He has been active in JSME(The Japan Society of Mechanical Engineers) and JEA(The Japan Electric Association) as code engineer since 2020.

Authors:

Kenichi Shibukuwa IHI Corporation
Jie Wen Jensenhurghes
Masahiro Takanashi IHI Corporation
Kenji Funasaki Toshiba