Validation of notch stress estimation schemes for different constraints,
strain gradients and loading conditions on low C-Mn steel
Abstract
The present study is aimed at validation of notch stress/ strain
estimation schemes such as classical Neuber, Hoffmann-Seeger and
recently developed Ince-Glinka method for Nuclear piping material (low
C-Mn steel). The study has considered different constraints, loading
conditions, various hole sizes to accommodate strain gradient variations
and equivalent peak strains. The notch stress field evaluated using
these schemes is compared with corresponding stress using
elastic-plastic Finite Element (FE) analyses. The comparisons have
brought out that the Hoffmann-Seeger scheme results in reasonably
accurate assessment of stress localization nearly for all constraint
geometries, loadings and strain gradients. However, the classical Neuber
scheme is more suitable for low constraint geometries and intermediate
constraint geometries whereas it results in under-estimation of maximum
principal stress for high constraint geometries, thereby leading to
over-prediction of fatigue life. Further, the suitability of energy
equivalence equations of Ince-Glinka model for individual stress
components, has been reviewed.