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Title: FY17 Status Report on the Initial EPP Finite Element Analysis of Grade 91 Steel

Abstract

This report describes a modification to the elastic-perfectly plastic (EPP) strain limits design method to account for cyclic softening in Gr. 91 steel. The report demonstrates that the unmodified EPP strain limits method described in current ASME code case is not conservative for materials with substantial cyclic softening behavior like Gr. 91 steel. However, the EPP strain limits method can be modified to be conservative for softening materials by using softened isochronous stress-strain curves in place of the standard curves developed from unsoftened creep experiments. The report provides softened curves derived from inelastic material simulations and factors describing the transformation of unsoftened curves to a softened state. Furthermore, the report outlines a method for deriving these factors directly from creep/fatigue tests. If the material softening saturates the proposed EPP strain limits method can be further simplified, providing a methodology based on temperature-dependent softening factors that could be implemented in an ASME code case allowing the use of the EPP strain limits method with Gr. 91. Finally, the report demonstrates the conservatism of the modified method when applied to inelastic simulation results and two bar experiments.

Authors:
 [1];  [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Nuclear Energy (NE)
OSTI Identifier:
1375457
Report Number(s):
ANL-ART-94
136949
DOE Contract Number:  
AC02-06CH11357
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Messner, M. C., and Sham, T. -L. FY17 Status Report on the Initial EPP Finite Element Analysis of Grade 91 Steel. United States: N. p., 2017. Web. doi:10.2172/1375457.
Messner, M. C., & Sham, T. -L. FY17 Status Report on the Initial EPP Finite Element Analysis of Grade 91 Steel. United States. doi:10.2172/1375457.
Messner, M. C., and Sham, T. -L. Sat . "FY17 Status Report on the Initial EPP Finite Element Analysis of Grade 91 Steel". United States. doi:10.2172/1375457. https://www.osti.gov/servlets/purl/1375457.
@article{osti_1375457,
title = {FY17 Status Report on the Initial EPP Finite Element Analysis of Grade 91 Steel},
author = {Messner, M. C. and Sham, T. -L.},
abstractNote = {This report describes a modification to the elastic-perfectly plastic (EPP) strain limits design method to account for cyclic softening in Gr. 91 steel. The report demonstrates that the unmodified EPP strain limits method described in current ASME code case is not conservative for materials with substantial cyclic softening behavior like Gr. 91 steel. However, the EPP strain limits method can be modified to be conservative for softening materials by using softened isochronous stress-strain curves in place of the standard curves developed from unsoftened creep experiments. The report provides softened curves derived from inelastic material simulations and factors describing the transformation of unsoftened curves to a softened state. Furthermore, the report outlines a method for deriving these factors directly from creep/fatigue tests. If the material softening saturates the proposed EPP strain limits method can be further simplified, providing a methodology based on temperature-dependent softening factors that could be implemented in an ASME code case allowing the use of the EPP strain limits method with Gr. 91. Finally, the report demonstrates the conservatism of the modified method when applied to inelastic simulation results and two bar experiments.},
doi = {10.2172/1375457},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Jul 01 00:00:00 EDT 2017},
month = {Sat Jul 01 00:00:00 EDT 2017}
}

Technical Report:

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