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The effects of multiple overloads and absorbed hydrogen on the fatigue strength of notched steel specimens
Author(s) -
KONDO Y.,
YAMANOUCHI T.
Publication year - 2010
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.2010.01462.x
Subject(s) - hydrogen , materials science , residual stress , ultimate tensile strength , residual strength , fatigue limit , structural engineering , reduction (mathematics) , durability , residual , stress (linguistics) , forensic engineering , composite material , stress concentration , strength of materials , fracture mechanics , engineering , chemistry , computer science , organic chemistry , linguistics , geometry , mathematics , philosophy , algorithm
It is well known that earthquakes can damage structures and machinery. After an earthquake, those components, which have been obviously damaged are scrapped and replaced, and most of the components which have not been obviously damaged will continue to be used even after earthquakes. However, as will be shown, the earthquake may have severely impaired the fatigue strength of such components by introducing unfavourable residual stresses and short cracks at stress raisers. In addition, if such components should contain hydrogen, an increasingly possible scenario for the hydrogen economy in the future, then it is shown that the loss of fatigue strength can be even greater. This paper explores the extent of fatigue degradation due to overloads and to absorbed hydrogen. It was shown that generation of small crack and tensile residual stress imposed by overloads caused substantial decrease of residual fatigue strength compared with that in the initial state. It was also shown that hydrogen enhanced more reduction. Hydrogen enhanced reduction in two ways. The crack generated by overloads grew deeper in hydrogen charged material. In addition to this, the reduction of Δ K th also occurred in hydrogen charged material. These two factors worked together to reduce the residual fatigue strength after multiple overloads.