FCP Report No. 169

eσ and eε Based Approaches to Multiaxial Notch Analysis

by

Volker B. Kottgen
Mark E. Barkey
Darrell F. Socie

Abstract

The analysis of notch stresses and strains is one of the key parts of fatigue life prediction of components and structures. In this paper two related approaches are introduced, covering the whole field from uniaxial to multiaxial non-proportional loading. The stress at the notch root computed by theory of elasticity, eσ, is introduced as the governing variable for elastic-plastic notch analysis. Although eσ is just a specially defined nominal stress, it eases notch analysis in comparison to using arbitrarily definable nominal stresses, especially for non-proportional multiaxial loading. Additionally an eε (strain) based approach is introduced and compared to the eσ approach. Both proportional and non-proportional loading are discussed, and compared to the approaches by HOFFMANN and SEEGER and by BARKEY.

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