Generalized approach to estimation of strains and stresses at blunt V-notches under non-localized creep

Geometrical discontinuities such as notches need to be carefully analysed by engineers because of the stress concentration generated by them. Notches become even more important when the component is subjected, in service, to very severe conditions, such as high-temperature fatigue and imposed viscoplastic behaviour such as creep. The knowledge of strains and stresses in such stress concentration zones is essential for an efficient and safe design process. The aim of the paper is to present an improvement and extension of the existing notch-tip creep stress-strain analysis method developed by Nuñez and Glinka, validated for U-notches only, to a wide variety of blunt V-notches. The key in obtaining the extension to blunt V-notches is the substitution of the Creager-Paris equations with the more generalized Lazzarin-Tovo solution, allowing a unified approach to the evaluation of linear elastic stress fields in the neighbourhood of both cracks and notches. Numerous examples have been analysed to date, and the stress fields obtained according to the proposed method were compared with appropriate finite element data, resulting in a very good agreement. In view of the promising results discussed in the paper, authors are considering possible further extension to sharp V-notches and cracks introducing the concept of the strain energy density.