A Preliminary Assessment of the Ke Factor Proposed in the EN13445 Standard for Fatigue Analysis of Unwelded Material

Abstract

This paper presents an investigation about the plasticity correction factor, Ke, proposed in the Part 3-Clause 18 of the EN13445 standard, for correction of the elastic stress ranges exceeding twice the yield stress, resulting from mechanical loading. The plasticity correction factors are analyzed using a calculation strategy based on a comparison between results from linear elastic and elastoplastic analyses. Several materials, elastoplastic models, and geometries are considered in the study. The performed analyses revealed, for an important number of the situations, an underestimation of the Ke factor when calculated according to the standard procedures. A greater emphasis should be dedicated in the standard to the elastoplastic analysis, since the fatigue resistance data presented in the standard are strain-life type data, overcoming the need for the plasticity correction factor. The elastoplastic analysis should be the preferred approach for evaluation of the strains/stresses for fatigue analysis.