Abstract
Plain bend bars made from FV566 martensitic stainless steel were extracted from the root of ex-service power plant turbine blades and several industry-relevant notch geometries were introduced. Some of the samples were shot peened. The notched bend bars were loaded plastically in the low-cycle fatigue regime and finite element (FE) modeling carried out to investigate the effects of changing notch geometry, combined with shot peening, on fatigue behaviors such as crack initiation, short crack growth, and coalescence. Shot peening damaged the notch surface, accelerating initiation behaviors, but had a lifetime-extending effect by retarding short crack growth in all tested notch geometries. At a total strain range higher than 1.2%, the lifetime extension benefit from shot peening was diminished due to compressive residual stress relaxation in the notch stress field. Notch geometry (and the associated varying constraint levels and stress/strain gradients) was found to have no notable difference on fatigue life when tested at identical notch-root strain ranges.
Original language | English |
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Article number | 14036 |
Pages (from-to) | 2845-2863 |
Number of pages | 19 |
Journal | Fatigue and Fracture of Engineering Materials and Structures |
Volume | 46 |
Issue number | 8 |
Early online date | 16 May 2023 |
DOIs | |
Publication status | Published - Aug 2023 |
Bibliographical note
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, providedthe original work is properly cited.
Funder
Engineering and Physical Sciences Research Council (EPSRC), UK, Grant/Award Number: EP/N509747/1; Natural Science Foundation of Jiangsu Province, Grant/Award Number: BK20210302Keywords
- constant amplitude
- low cycle fatigue
- notch field
- notches
- short crack growth
- stainless steel
ASJC Scopus subject areas
- Materials Science(all)
- Mechanics of Materials
- Mechanical Engineering